Jo Stenehjem

• Rasmussen, Anders Johan Orland; Nordseth, Trond; Stenehjem, Jo; Gran, Jon Michael; Lien, Lars & Rosseland, Leiv Arne (2026). Risk of Suicide in Patients With Traumatic Injuries. JAMA Network Open. 9(1). doi: 10.1001/jamanetworkopen.2025.54168. Full text in Research Archive Show summary

  Importance Previous studies suggest that critically injured patients are at increased risk of suicide following discharge, but these have mainly been single-center studies or had limited data on comorbidities and socioeconomic factors. Objective To examine the risk of suicide after hospitalization for traumatic injuries. Design, Setting, and Participants This nationwide register-based cohort study used data from 5 Norwegian nationwide health registries and Statistics Norway between 2014 and 2020. Patients registered in the Norwegian Trauma Registry (NTR) for whom trauma team activation at hospital arrival was mandated by national guidelines between 2015 and 2018 were matched to general-population controls on gender and birth year in a 1:10 ratio according to a matched cohort design. Patients discharged alive were followed-up for a minimum of 2 years. All Norwegian hospitals treating patients with traumatic injuries provide data to the NTR. The final analysis was conducted in April 2025. Exposures Traumatic injury, admitted to hospital, and registered in the NTR. Main Outcomes and Measures The outcome of interest was suicide, as registered in the Norwegian Cause of Death Registry. Cumulative incidence ratios (CIR) of suicide with 95% CIs, taking nonsuicidal death as a competing event into account, were estimated. Adjustments for Charlson Comorbidity Index, previous psychiatric illness, and socioeconomic position (SEP) were conducted using inverse probability of treatment weights. Results A total of 25 536 patients with traumatic injuries (165 897 [67%] male; mean [SD] age, 41 [23] years) were matched to 247 095 controls, with a mean (SD) age of 41 (23) years and 68% male. The cumulative incidences of suicide were 0.18% at 2 years and 0.34% and 5 years for patients with traumatic injuries and 0.02% at 2 years and 0.05% at 5 years for controls (2-year CIR, 9.3 [95% CI, 5.4-13.0]; 5-year CIR, 6.9 [95% CI, 4.4-9.1]). Patients with traumatic injury were older at the age of suicide compared with controls (mean [SD] age, 43 [19] years vs 36 [17] years; P  = .03) and female patients with traumatic injury had higher incidence of suicide compared with female controls (36% vs 17%; P  = .005). Conclusions and Relevance In this cohort study of patients in Norway discharged alive after critical injury, a 9-fold increased risk of suicide after 2 years was observed. These findings suggest that follow-up is warranted for possible psychological distress in this patient group.

• Heibati, Behzad; Soursou, Georgia; Abimbola, Samuel; Charisiadis, Pantelis; Eleftheriou, Lygia & Berge, Leon Alexander Mclaren [Show all 8 contributors for this article] (2025). BTEX chrono-metabolism and leukemogenic effects of night shift work in workers of gasoline stations: the EXPOSOWORK prospective panel study in Bulgaria. Journal of the National Cancer Center. 5(5), p. 546–546. doi: 10.1016/j.jncc.2025.01.006. Full text in Research Archive
• Shala, Nita Kaupang; Veierød, Marit Bragelien; Babigumira, Ronnie; Berge, Leon Alexander Mclaren; Samuelsen, Sven Ove & Kirkeleit, Jorunn [Show all 14 contributors for this article] (2025). Occupational exposures and kidney cancer among 25 000 male offshore petroleum industry workers: relative risks and healthy worker survivor bias. American Journal of Epidemiology. ISSN 0002-9262. 195(1), p. 81–91. doi: 10.1093/aje/kwaf039. Full text in Research Archive Show summary

  Kidney cancer has been a suspected occupational disease in petroleum workers. Health conditions that are linked to kidney cancer may prompt termination or change of work, and thereby restrict occupational exposures in high-risk individuals, creating a healthy worker survivor bias (HWSB). We examined associations between occupational exposures and kidney cancer among males in the Norwegian Offshore Petroleum Workers (NOPW) cohort using a case-cohort design, with 169 incident cancers identified by linkage to national registry data (1999-2021) and a subcohort of 2090 non-cases, all employed 1965-1998. Relative risks (hazard ratios, HRs) by cumulative exposure to benzene, crude oil, chlorinated degreasing agents (CDA), asbestos, welding fumes, or surface treatment (priming, painting), were estimated by weighted Cox regression. Inverse exposure-response trends suggested HWSB, reinforced by analyses of necessary components of HWSB. Bias was partly alleviated by adjustment for total employment duration, and by 20-year lagging of cumulative exposure to benzene, crude oil, or CDA. Workers in surface treatment (ever vs. never) showed increased HR=2.22, 95% confidence interval 1.04-4.72 (9 cases, only). For asbestos and welding fumes, the initial inverse trends largely remained after adjustment. In sum, we could neither confirm nor exclude an occupational impact on kidney cancer.

• Heibati, Behzad; Stenehjem, Jo; Pletea, Elisabeta; Turner, Michelle C.; Schernhammer, Eva S. & McElvenny, Damien M. [Show all 9 contributors for this article] (2025). Indirect adjustment of tobacco smoking in occupational studies of lung cancer: A systematic review of the available methods and their applications. Cancer Epidemiology. ISSN 1877-7821. 97, p. 1–14. doi: 10.1016/j.canep.2025.102820. Full text in Research Archive
• Babigumira, Ronnie; Veierød, Marit Bragelien; Larsen, Inger Kristin; Berge, Leon Alexander Mclaren; Shala, Nita Kaupang & Marjerrison, Niki [Show all 22 contributors for this article] (2025). Benzene exposure and risk of colorectal cancer by anatomical subsite in the Norwegian offshore petroleum workers cohort. Environmental Research. ISSN 0013-9351. 276, p. 1–9. doi: 10.1016/j.envres.2025.121407. Full text in Research Archive Show summary

  Objective: To investigate the association between low levels of benzene exposure (≤0.879 parts per million [ppm]-years) and risk of colorectal cancer (CRC) including its anatomical subsites. Methods: Among 25,347 male workers in the Norwegian Offshore Petroleum Workers (NOPW) cohort with offshore work history (1965–1998), 455 CRC cases were diagnosed 1999–2021. We compared these with a subcohort (n = 2031) drawn from the full cohort. Work histories were linked to a previously developed industry-specific benzene job-exposure matrix (JEM). Cox regression for case-cohort analyses was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for CRC, adjusted for age, body mass index, smoking, alcohol intake, red/processed meat intake, and physical activity. Results: Risks of CRC increased with increasing benzene exposure. For all CRC, the HRs (95% CI) for the most exposed [quartile 4] vs. the unexposed were 1.32 (0.96 to 1.81, [0.177–0.879 ppm-years]; p-trend = 0.085) for cumulative, 1.52 (1.11 to 2.07, [17–34 years]; p-trend = 0.032) for duration, and 1.56 (1.15 to 2.12, [0.015–0.046 ppm]; p-trend = 0.005) for average intensity of benzene exposure. For right-sided colon cancer, the association was most evident for exposure duration (HR = 2.25 (1.33 to 3.80), quartile 4 [17–34 years] vs. unexposed; p-trend = 0.007). Sensitivity analyses showed consistent associations. Conclusion: This study found positive exposure-response associations between low-level benzene exposure and CRC risk in offshore petroleum workers. These findings add to emerging evidence that benzene can be associated with solid tumours including lung and bladder, which potentially has important occupational and public health implications.

• Wan, Wenxin; Peters, Susan; Portengen, Lützen; Babigumira, Ronnie; Stenehjem, Jo & Richardson, David [Show all 7 contributors for this article] (2024). Occupational Benzene Exposure and Lung Cancer in Human Studies: A Systematic Review and Meta-Analysis. Environmental Health Perspectives. ISSN 0091-6765. 132(12). doi: 10.1289/EHP15086. Full text in Research Archive Show summary

  Background: Benzene is classified as carcinogenic to humans based on evidence that benzene causes acute myeloid leukemia. However, there is limited evidence that benzene causes lung cancer. Objectives: We performed a systematic review, quality assessment, and meta-analysis of published cohort and case–control studies on the association between occupational benzene exposure and lung cancer risk. Methods: We reviewed the relevant human epidemiological studies from PubMed and Embase databases to 19 August 2024. Data extraction included study characteristics, effect estimates, and exposure assessment details. Two investigators independently evaluated study quality using the Newcastle-Ottawa scale (NOS) framework and exposure assessment quality based on a priori criteria. Six risk of bias (ROB) domains were constructed from the NOS criteria to identify and quantify possible biases and their impacts on parameter estimates. Meta-analysis relative risk (pooled RR) and associated confidence intervals were calculated using random-effects models, and a flexible exposure–response meta-regression was fitted to assess the shape of the association. Subgroup analyses were conducted to explore the consistency of results. Results: Of 252 articles identified, 13 studies covering 366,975 participants (17,030 lung cancer cases) were included in our analysis. The meta-analysis of ever occupational benzene exposure showed an elevated risk of lung cancer (pooled RR=1.14; 95% CI: 1.03, 1.27; 𝐼⁢²=72). Subgroup analyses revealed that larger pooled RRs in studies based on highly exposed groups had higher overall quality and better exposure assessments and included both males and females (as opposed to only males). A positive linear trend was observed in the exposure–response meta-analysis. Discussion: Our meta-analysis supports an association between occupational benzene exposure and an increased risk of lung cancer. https://doi.org/10.1289/EHP15086

• Jørgenrud, Benedicte Marie; Bråthen, Camilla Christin; Stenehjem, Jo; Kristiansen, Thomas; Rosseland, Leiv Arne & Bogstrand, Stig Tore (2024). Identifying excessive chronic alcohol use with phosphatidylethanol in patients with suspected severe injury-results from the IDART study. Alcohol and Alcoholism. ISSN 0735-0414. 59(3), p. 1–8. doi: 10.1093/alcalc/agae014. Full text in Research Archive Show summary

  Introduction: Acute and chronic alcohol use are well-known risk factors for accidents and injuries, and concurrent psychoactive drug use can increase injury risk further. Phosphatidylethanol (PEth) 16:0/18:1 is a biomarker used to determine alcohol consumption the previous 3-4 weeks. The aim was to investigate the prevalence of chronic alcohol use in trauma patients, as determined by PEth 16:0/18:1 concentrations, and how excessive chronic alcohol use relate to demographic variables, injury mechanisms and drug use. Setting: Patients received at Norwegian trauma hospitals from March 2019 to February 2020. The study is part of the Impairing Drugs and Alcohol as Risk factors for Traumatic Injuries study. Methods: All patients aged ≥ 16 years received with trauma team were included in the study. Data on injury date and mechanism, gender and age was registered. Blood samples were analyzed for 22 psychoactive medicinal and illicit drugs, ethanol and phosphatidylethanol 16:0/18:1. Regression analyses were conducted to assess associations between alcohol use and gender, age, injury mechanism and drug use. Results and conclusion: Of the 4845 patients included in the study, 10% had PEth 16:0/18:1 concentration ≥ 600 nM (~430 ng/mL), indicative of excessive chronic alcohol use. Being male, between 44-61 years old, involved in violence, and testing positive for medicinal drugs was associated with excessive chronic alcohol use.Excessive chronic alcohol use was common among males, middle-aged, patients with violence as injury mechanism and those with medicinal drug use. These findings emphasize the need to detect and treat excessive chronic alcohol use among trauma patients.

• Sødal, Hild Flatmark; Nordseth, Trond; Rasmussen, Anders Johan Orland; Rosseland, Leiv Arne; Stenehjem, Jo & Gran, Jon Michael [Show all 8 contributors for this article] (2024). Risk of epilepsy after traumatic brain injury: a nationwide Norwegian matched cohort study. Frontiers in Neurology. 15. doi: 10.3389/fneur.2024.1411692. Full text in Research Archive Show summary

  Background: Post-traumatic epilepsy (PTE) is a well-known complication of traumatic brain injury (TBI). Although several risk factors have been identified, prediction of PTE is difficult. Changing demographics and advances in TBI treatment may affect the risk of PTE. Our aim was to provide an up-to-date estimate of the incidence of PTE by linking multiple nationwide registers. Methods: Patients with TBI admitted to hospital 2015-2018 were identified in the Norwegian Trauma Registry and matched to trauma-free controls on sex and birth year according to a matched cohort design. They were followed up for epilepsy in nationwide registers 2015-2020. Cumulative incidence of epilepsy in TBI patients and controls was estimated taking competing risks into account. Analyses stratified by the Abbreviated Injury Scale (AIS) severity score, Glasgow Coma Scale score and age were conducted for the TBI group. Occurrence of PTE in different injury types was visualized using UpSet plots. Results: In total, 8,660 patients and

• Berge, Leon Alexander Mclaren; Shala, Nita Kaupang; Barone-Adesi, Francesco; Hosgood, H Dean; Samuelsen, Sven Ove & Bråtveit, Magne [Show all 13 contributors for this article] (2024). Exposure to fibres and risk of pleural mesothelioma in the Norwegian Offshore Petroleum Workers cohort. Occupational and Environmental Medicine. ISSN 1351-0711. 81(7), p. 331–338. doi: 10.1136/oemed-2024-109424. Full text in Research Archive Show summary

  Objectives Pleural mesothelioma is a rare respiratory cancer, mainly caused by inhalation of asbestos fibres. Other inorganic fibres are also suggested risk factors. We aimed to investigate the association between exposure to asbestos or refractory ceramic fibres (RCFs) and pleural mesothelioma among male Norwegian offshore petroleum workers. Methods Among 25 347 men in the Norwegian Offshore Petroleum Workers (NOPW) cohort (1965–1998), 43 pleural mesothelioma cases were identified through the Cancer Registry of Norway (1999–2022). A case–cohort study was conducted with 2095 randomly drawn non-cases from the cohort. Asbestos and RCF exposures were assessed with expert-made job-exposure matrices (JEMs). Weighted Cox regression was used to estimate HRs and 95% CIs, adjusted for age at baseline and pre-offshore employment with likely asbestos exposure. Results An increased risk of pleural mesothelioma was indicated for the highest versus lowest tertile of average intensity of asbestos (HR=1.21, 95% CI: 0.57 to

• Marjerrison, Niki; Grimsrud, Tom Kristian; Hansen, Johnni; Martinsen, Jan Ivar; Nordby, Karl-Christian & Olsen, Raymond [Show all 9 contributors for this article] (2024). Occupational exposures of firefighting and prostate cancer risk in the Norwegian Fire Departments Cohort. Scandinavian Journal of Work, Environment and Health. ISSN 0355-3140. 51(2), p. 100–110. doi: 10.5271/sjweh.4202. Full text in Research Archive Show summary

  Objectives Excess incidence of prostate cancer (PC) is frequently observed among firefighters; however, the association with specific occupational exposures of firefighting, as well as the influence of a medical surveillance bias, remains unclear. Our aim was to study PC risk within a firefighter cohort, applying indicators of exposures. Methods We used indicators of various firefighting exposures to examine PC risk among men in the Norwegian Fire Departments Cohort (N=4251). Incident PC cases, including clinical characteristics, were obtained from the Cancer Registry of Norway (1960–2021). Cox regression was used to estimate hazard ratios (HR) by cumulative exposure in tertiles (reference: lowest) for all, aggressive, and indolent PC, with adjustment for age and birth cohort. The cumulative incidence of PC across birth cohorts and diagnostic periods was examined. Results No clear associations emerged for any of the exposure indicators, although we observed an HR of 1.31 [95% confidence interval (CI) 0.63–2.72] for aggressive PC in the highest tertile of fire exposure score and 1.31 (95% CI 0.60–2.89) for indolent PC in the highest tertile of inhalation score. Assessment of cumulative incidence demonstrated a greater number of diagnoses at younger ages after 1990, particularly for indolent and unclassifiable PC. Conclusions We found little support for an association between firefighting exposures and PC risk. However, our study had few cases in analyses by clinical stage. Challenges in studies of firefighters’ PC risk remain, including difficulties in exposure characterization and the unclear magnitude of a medical surveillance bias.

• Gjerde, Hallvard; Jamt, Ragnhild Elén Gjulem; Stenehjem, Jo & Bogstrand, Stig Tore (2024). Substance use and driver fatality in Norway: An expanded case-control study. Traffic Injury Prevention. ISSN 1538-9588. 26(1). doi: 10.1080/15389588.2024.2392274. Full text in Research Archive Show summary

  Objective Using alcohol or psychoactive drugs before driving a motor vehicle may increase the risk of crash involvement, injury, and death. This is better documented for alcohol than for drugs. The aim of this study was to expand a previous case-control study on substance use and driver fatality by doubling the number of cases and controls, and hence improve the statistical power and enable the analysis of combined substance use. Methods We collected data on alcohol and drug use from all 1197 drivers of cars and vans who were fatally injured in road traffic crashes in Norway between 2005 and 2020 (‘cases’) by analyzing blood samples or reviewing other information on substance use. We also collected data on alcohol and drug use among 17,219 drivers in random road traffic (‘controls’) by analyzing oral fluid samples. Substance use was converted to dichotomous variables (no use/use). We used unconditional logistic regression to estimate adjusted odds ratios (aORs) with 95% confidence intervals (CIs) of driver fatality for mutually exclusive substance groups, adjusted for sex, age, geographic region, urban centrality class, and time interval of the week. Results Compared to no substance use, the aOR (95% CI) for driver fatality was for alcohol 91 (61-137), stimulants (primarily amphetamines) aOR 22 (9-56), benzodiazepines and z-hypnotics (BZDs) aOR 4.0 (2.7-5.9), tetrahydrocannabinol (THC) aOR 3.4 (1.7-6.7), and opioids aOR 1.4 (0.4-4.9). The aOR for any polysubstance use was 168 (96-297). The combinations of BZDs with stimulants or THC were associated with markedly higher aORs for driver fatality than the use of single substance groups. Conclusions Alcohol and polysubstance use are the most important predictors of fatal injury, followed by stimulants.

• Shala, Nita Kaupang; Stenehjem, Jo; Babigumira, Ronnie; Liu, Fei-Chih; Berge, Leon Alexander Mclaren & Silverman, Debra T. [Show all 16 contributors for this article] (2023). Exposure to benzene and other hydrocarbons and risk of bladder cancer among male offshore petroleum workers. British Journal of Cancer. ISSN 0007-0920. 129(5), p. 838–851. doi: 10.1038/s41416-023-02357-0. Full text in Research Archive Show summary

  Background Occupational exposures constitute the second leading cause of urinary bladder cancer after tobacco smoking. Increased risks have been found in the petroleum industry, but high-quality exposure data are needed to explain these observations. Methods Using a prospective case-cohort design, we analysed 189 bladder cancer cases (1999–2017) and 2065 randomly drawn non-cases from the Norwegian Offshore Petroleum Workers cohort. Cases were identified in the Cancer Registry of Norway, while work histories (1965–1998) and lifestyle factors were recorded by questionnaire at baseline (1998). Occupational petroleum-related hydrocarbon exposures were assessed by expert-developed job-exposure matrices. Hazard ratios were estimated by weighted Cox-regressions, adjusted for age, tobacco smoking, education, and year of first employment, and with lagged exposures. Results Increased risks were found in benzene-exposed workers, either long-term exposure (≥18.8 years, HR = 1.89, 95% CI: 1.14–3.13; p-trend = 0.044) or high-level cumulative benzene exposure (HR = 1.60, 95% CI: 0.97–2.63; p-trend = 0.065), compared with the unexposed. Associations persisted with 20-year exposure lag. No associations were found with skin or inhalation exposure to crude oil, mineral oil (lubrication, hydraulics, turbines, drilling), or diesel exhaust. Conclusions The results suggest that exposures in the benzene fraction of the petroleum stream may be associated with increased bladder cancer risk.

• Babigumira, Ronnie; Veierød, Marit Bragelien; Hosgood, H. Dean; Samuelsen, Sven Ove; Bråtveit, Magne & Kirkeleit, Jorunn [Show all 13 contributors for this article] (2023). Benzene exposure and risk of lung cancer in the Norwegian Offshore Petroleum Worker cohort: a prospective case-cohort study. Occupational and Environmental Medicine. ISSN 1351-0711. 81(1). doi: 10.1136/oemed-2023-109139. Full text in Research Archive Show summary

  Objective The objective of our study was to examine whether occupational exposure to benzene is associated with lung cancer among males in the Norwegian Offshore Petroleum Workers cohort. Methods Among 25 347 male offshore workers employed during 1965–1998, we conducted a case-cohort study with 399 lung cancer cases diagnosed between 1999 and 2021, and 2035 non-cases sampled randomly by 5-year birth cohorts. Individual work histories were coupled to study-specific job-exposure matrices for benzene and other known lung carcinogens. Weighted Cox regression was used to estimate HRs and 95% CIs for the associations between benzene exposure and lung cancer, by major histological subtypes, adjusted for age, smoking and occupational exposure to welding fumes, asbestos and crystalline silica. Missing data were imputed. Results For lung cancer (all subtypes combined), HRs (95% CIs) for the highest quartiles of benzene exposure versus unexposed were 1.15 (0.61 to 2.35) for cumulative exposure, 1.43 (0.76 to 2.69) for duration, and 1.22 (0.68 to 2.18) for average intensity (0.280≤P-trend≤0.741). For 152 adenocarcinoma cases, a positive trend was observed for exposure duration (P-trend=0.044). Conclusions In this cohort of offshore petroleum workers generally exposed to low average levels of benzene, we did not find an overall clear support for an association with lung cancer (all subtypes combined), although an association was suggested for duration of benzene exposure and adenocarcinoma. The limited evidence might be due to restricted statistical power.

• Liu, Fei-Chih; Veierød, Marit Bragelien; Kjærheim, Kristina; Robsahm, Trude Eid; Ghiasvand, Reza & Hosgood, H Dean [Show all 17 contributors for this article] (2022). Night shift work, chemical coexposures and risk of female breast cancer in the Norwegian Offshore Petroleum Workers (NOPW) cohort: A prospectively recruited case-cohort study. BMJ Open. 12(1). doi: 10.1136/bmjopen-2021-056396. Full text in Research Archive Show summary

  Objectives This study examined the association between night shift work and risk of breast cancer, overall and by hormone receptor subtype, among females in the Norwegian Offshore Petroleum Workers (NOPW) cohort. We also examined the association of coexposure (chlorinated degreasers and benzene) and breast cancer risk, and possible interaction with work schedule. Design Prospectively recruited case- cohort study within the NOPW cohort. Setting Female offshore petroleum workers active on the Norwegian continental shelf. Participants 600 female workers (86 cases and 514 non- cases) were included in the study. We excluded workers that died or emigrated before start of follow-up, had missing work history, were diagnosed with breast cancer or other prior malignancy (except non-melanoma skin cancer) before start of follow-up. Results No overall association was found between breast cancer risk and work schedule (HR 0.87, 95% CI 0.52 to 1.46 for work schedule involving night shift vs day shift only). There was no significant association between work schedule and risk of any breast cancer subtype. No significant interactions were found between work schedule and chemical coexposures (breast cancer overall Pinteraction chlorinated degreasers =0.725 and Pinteraction benzene =0.175). Conclusions Our results did not provide supporting evidence that work schedule involving night shift affects breast cancer risk in female offshore petroleum workers, but should be considered cautiously due to few cases. Further studies with larger sample sizes are warranted

• Smeland, Knut Bjøro; Holte, Harald; Fagerli, Unn-Merete; Bersvendsen, Hanne Skjerven; Hjermstad, Marianne Jensen & Loge, Jon Håvard [Show all 13 contributors for this article] (2022). Total late effect burden in long-term lymphoma survivors after high-dose therapy with autologous stem-cell transplant and its effect on health-related quality of life. Haematologica. ISSN 0390-6078. 107(11), p. 2698–2707. doi: 10.3324/haematol.2021.280413. Full text in Research Archive Show summary

  Lymphoma survivors after high-dose therapy with autologous stem-cell transplant (HDT-ASCT) are at risk of several late effects, which might impair their health-related quality of life (HRQoL). We assessed the total late effect burden in this population, and how it affects HRQoL. All lymphoma survivors treated with HDT-ASCT as adults in Norway between 1987 and 2008 were identified, and 271 (68%) attended both a comprehensive clinical assessment and completed a questionnaire. Severity of 45 conditions in 12 organ-system categories were graded as mild, moderate, severe or life-threatening, according to a modified version of CTCAEv4.03. At a median of 8 years after HDT-ASCT, 98% of survivors had at least one moderate or more severe late effect and 56% had severe or life-threatening late effects. Fourteen percent had low, 39% medium and 47% high late effect burden, defined as having moderate or more severe late effects in 0-1, 2-3 and >3 organsystems, respectively. Female sex, increasing age, B-symptoms at diagnosis and >1 treatment line prior to HDT-ASCT were independently associated with having high late effect burden. The survivors had significantly poorer physical and mental HRQoL assessed by the Short Form-36 compared to age- and sex-matched controls. The prevalence of poor physical and mental HRQoL increased with higher late effect burden (both P<0.001), and the low burden group had better physical HRQoL than controls (P<0.001). In conclusion, lymphoma survivors after HDT-ASCT have impaired HRQoL, seemingly driven by a high late effect burden. This highlights the importance of prevention, regular assessments for early detection and treatment of late effects and modifiable risk factors.

• Stenehjem, Jo S.; Støer, Nathalie Charlotte; Ghiasvand, Reza; Grimsrud, Tom Kristian; Babigumira, Ronnie & Rees, Judy R. [Show all 11 contributors for this article] (2022). Prediagnostic serum 25-hydroxyvitamin D and leptin in relation to melanoma-specific death and overall death. Pigment Cell & Melanoma Research. ISSN 1755-1471. 35(2), p. 280–284. doi: 10.1111/pcmr.13026. Full text in Research Archive
• Berge, Leon Alexander Mclaren; Liu, Fei-Chih; Grimsrud, Tom Kristian; Babigumira, Ronnie; Støer, Nathalie Charlotte & Kjærheim, Kristina [Show all 15 contributors for this article] (2022). Night shift work and risk of aggressive prostate cancer in the Norwegian Offshore Petroleum Workers (NOPW) cohort. International Journal of Epidemiology. ISSN 0300-5771. 52(4), p. 1003–1014. doi: 10.1093/ije/dyac235. Full text in Research Archive Show summary

  Background: Night shift work may acutely disrupt the circadian rhythm, with possible carcinogenic effects. Prostate cancer has few established risk factors though night shift work, a probable human carcinogen, may increase the risk. We aimed to study the association between night shift work and chlorinated degreasing agents (CDAs) as possible endocrine disrupters in relation to aggressive prostate cancer as verified malignancies. Methods: We conducted a case-cohort study on 299 aggressive prostate cancer cases and 2056 randomly drawn non-cases in the Norwegian Offshore Petroleum Workers cohort (1965-98) with linkage to the Cancer Registry of Norway (1953-2019). Work history was recorded as years with day, night, and rollover (rotating) shift work, and CDA exposure was assessed with expert-made job-exposure matrices. Weighted Cox regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for aggressive prostate cancer, adjusted for education and year of first employment, stratified by 10-year birth cohorts, and with 10, 15, and 20 years of exposure lag periods. Results: Compared with day work only, an increased hazard of aggressive prostate cancer (HR = 1.86, 95% CI 1.18-2.91; P-trend = 0.046) was found in workers exposed to ≥19.5 years of rollover shift work. This persisted with longer lag periods (HR = 1.90, 95% CI 0.92-3.95; P-trend = 0.007). The exposure-hazard curve for a non-linear model increased linearly (HRs ≥1.00) for 18-26 years of rollover shift work. No association was found with CDA exposure. Conclusions: Long-term exposure to rollover shift work may increase the hazard of aggressive prostate cancer in offshore petroleum workers.

• Ghiasvand, Reza; Berge, Leon Alexander Mclaren; Kulle, Bettina; Stenehjem, Jo Steinson; Heir, Trond & Karlstad, Øystein [Show all 11 contributors for this article] (2022). Use of antihypertensive drugs and risk of cutaneous melanoma: A nationwide nested case-control study. International Journal of Epidemiology. ISSN 0300-5771. 52(3), p. 887–898. doi: 10.1093/ije/dyac223. Full text in Research Archive Show summary

  Abstract Background Most antihypertensives can induce dermal photosensitivity, which may increase melanoma risk. However, corroborating evidence is limited. We examined the associations between use of antihypertensives and melanoma risk. Methods A nationwide nested case-control study was conducted using data from the Cancer Registry of Norway, the National Registry and the Norwegian Prescription Database in 2004–15. Ten controls were randomly selected for each melanoma case, matched on sex and birth year. The study included 12 048 cases and 117 895 controls. We estimated rate ratios (RRs) with 95% confidence intervals (CIs). All analyses were adjusted for ambient ultraviolet radiation (UVR). We additionally performed active comparator analyses, and sensitivity analyses by only including new users, distinguishing between exclusive and mixed users, allowing for different latency periods, and subgroup analyses by melanoma subtype and clinical stage. Results Compared with non-use, we observed a slightly increased melanoma risk in users of diuretics (RR 1.08, CI 1.01–1.15), calcium-channel blockers (RR 1.10, CI 1.04–1.18) and drugs affecting the renin-angiotensin system (RR 1.10, CI 1.04–1.16), but not for beta blockers (RR 0.97, CI 0.92–1.03). We found no heterogeneity of associations by melanoma subtype or clinical stage and no dose-response relationship between the cumulative defined daily doses (DDDs) and melanoma. No interaction was found between cumulative DDDs and ambient UVR. Conclusions Weak associations, with lack of a dose-response relationship and lack of interactions with ambient UVR, in the DDD analysis in this nationwide study do not support a causal relationship between antihypertensives and melanoma risk.

• Berge, Leon Alexander Mclaren; Grimsrud, Tom Kristian; Babigumira, Ronnie; Støer, Nathalie Charlotte; Shala, Nita Kaupang & Veierød, Marit Bragelien [Show all 7 contributors for this article] (2022). Cancer epidemiology in practice: Working notes on cancer history-based selection and censoring. Norsk Epidemiologi. ISSN 0803-2491. 30(1-2), p. 107–112. doi: 10.5324/nje.v30i1-2.4986. Full text in Research Archive Show summary

  Researchers conducting observational studies of exposure-cancer associations must make decisions regarding the selection and censoring of study subjects with respect to their cancer history. Given available information, this may include cancers prior to start of follow-up (prevalent cases), and multiple primary cancers (MPCs) at the same or different time-points during follow-up. The choice of analytical strategy may have implications for statistical power and for potential biases. We discuss herein two approaches, the “all cancer approach” and the “first primary cancer approach”. Each contains a set of criteria, primarily for, but not limited to, cohort studies of exposure-cancer associations. Both approaches exclude subjects with prevalent cancers at start of follow-up to avoid information and selection bias but differ in terms of case definition and censoring criteria. In the “all cancer approach”, subjects are censored on non-eligible cancer subtypes of the cancer under study, though subjects with MPCs are not censored on other incident cancers preceding or occurring simultaneously (at time of diagnosis) with the cancer under study. To limit the influence of prior treatment regimens, the “first primary cancer approach” censors subjects upon any first primary incident cancer not under study, including any “simultaneous” MPCs, as well as non-eligible subtypes of the cancer under study. Depending on the cancer under study, these approaches may yield different estimates of the exposure-cancer association and may in this regard be utilized for sensitivity analyses. These alternative approaches are presented and discussed here as a potential resource and source of further discussion for peers in the field of cancer epidemiology.

• Vasconcelos, Gisela Mafalda Sa Pereira de; Stenehjem, Jo S.; Axelsson, Stefan & Sæves, Rønnaug Ingun (2022). Craniofacial and dentoalveolar morphology in individuals with Prader–Willi syndrome: a case-control study. Orphanet Journal of Rare Diseases. 17(1). doi: 10.1186/s13023-022-02222-y. Full text in Research Archive Show summary

  Background Prader–Willi syndrome (PWS) is a complex multisystem genetic disorder with distinct genetic and clinical features. Among other clinical symptoms, PWS is characterized by severe infantile hypotonia with feeding problems, childhood onset hyperphagia, obesity, scoliosis, short stature combined with growth hormone deficiency and developmental delay. PWS is associated with facial dysmorphology, orofacial dysfunction, oral abnormalities, low salivary flow and subsequent severe tooth wear. Little is known about the craniofacial growth direction or dental and skeletal relationships in individuals with PWS in different ages. The purpose of this study was to assess the craniofacial and dentoalveolar characteristics and to investigate the craniofacial growth direction separately in children, young adults and adults with PWS, using a cephalometric analysis of lateral cephalograms. Results Lateral cephalograms of 42 individuals with a confirmed genetic diagnosis of PWS were analysed and divided into three groups according to their age: Children (< 12 years), young adults (12–20 years) and adults (> 20 years). Cephalometric variables were compared between PWS patients and controls by age and sex. Significant deviations and distinct craniofacial patterns were found in children, young adults and adults with PWS compared with the control group. Children showed retrognatic mandible with a skeletal class II relationship, posterior growth direction and longer anterior face height. The young adults had smaller cranial base angle, a skeletal class II pattern and a higher anterior lower face than the control group. Adults with PWS had a prognathic mandible, skeletal class III relationship with anterior growth direction, more retroclined lower incisors and proclined upper incisors than the controls. Similar results were found when comparing the three groups with PWS; the adults had a prognathic mandible, skeletal class III pattern and anterior growth direction. Children had a retropositioned mandibula, skeletal class II relationship and posterior growth direction. Conclusion This study may contribute to a better understanding of the craniofacial growth pattern in children, young adults and adults with PWS and may have a clinical importance when planning dental treatment, such as prosthodontics and/or orthodontics.

• Liu, Fei-Chih; Grimsrud, Tom Kristian; Veierød, Marit Bragelien; Robsahm, Trude Eid; Ghiasvand, Reza & Babigumira, Ronnie [Show all 8 contributors for this article] (2021). Ultraviolet radiation and risk of cutaneous melanoma and squamous cell carcinoma in males and females in the Norwegian Offshore Petroleum Workers cohort. American Journal of Industrial Medicine. ISSN 0271-3586. 64, p. 496–510. doi: 10.1002/ajim.23240. Full text in Research Archive Show summary

  Background Increased risk of cutaneous melanoma and squamous cell carcinoma (SCC) has been reported among petroleum workers, but few studies include females, exposure data on ultraviolet radiation (UVR), and potential confounding factors. We aimed to examine UVR exposure in relation to risk of melanoma and SCC among male and female offshore petroleum workers. We also examined the association between UVR exposure and melanoma (Breslow) thickness. Methods The Norwegian Offshore Petroleum Workers (NOPW) cohort (n = 27,917) holds information on sunbathing, indoor tanning, sunburns, sunscreen use, and other lifestyle factors recorded in 1998. Linkage to the Cancer Registry of Norway gave information on cancer diagnosis through 2017. We used Cox and logistic regression to estimate hazard ratios (HRs) of skin cancer and odds ratios (OR) of thick (≥1 mm) melanomas, respectively, with 95% confidence intervals (CIs). Results Melanoma risk increased with increasing frequency of sunbathing after age 20 (ptrend = 0.031), sunburn average intensity (ptrend = 0.028), and sunscreen use (HR = 2.16; 95% CI: 1.42 -3.27 for almost always vs. never/rarely). The risk of thick melanoma was inversely associated with sunbathing frequency after age 20 (OR = 0.38; 95% CI: 0.16 - 0.90 for ≥4 weeks/year vs. 1 week/year). SCC risk increased with increasing frequency of indoor tanning after age 20 (HR = 2.72; 95% CI: 1.22 - 6.05 for ≥3 times/months vs. never), sunburn average intensity (ptrend < 0.001), and sunscreen use (ptrend < 0.001). Conclusions Our results support associations between UVR exposure and skin cancer risk in male and female offshore petroleum workers. This occupational group may be especially relevant for targeted sun protection advice.

• Hektoen, Helga; Robsahm, Trude Eid; Stenehjem, Jo S.; Axcrona, Karol; Babigumira, Ronnie & Mondul, Alison M. [Show all 8 contributors for this article] (2021). Vitamin D and vitamin D-binding protein and risk of bladder cancer: A nested case-control study in the Norwegian Janus Serum Bank Cohort. Cancer Medicine. 10(12), p. 4107–4116. doi: 10.1002/cam4.3960. Full text in Research Archive Show summary

  Background High circulating levels of vitamin D (25(OH)D) are suggested to reduce the risk of urinary bladder cancer (BC), but the evidence is weak, and several studies lack sufficient adjustment for potential confounders (e.g., smoking, body mass index (BMI), and physical activity). Moreover, few studies have investigated the role of vitamin D-binding protein (DBP) in this context. We conducted a matched nested case–control study including 378 cases and 378 controls within the Norwegian population-based Janus cohort, using serum collected 5–41 years prior to diagnosis, to study 25(OH)D and BC risk, by taking circulating DBP into account. Methods Cox regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs), for 25(OH)D, DBP, and the molar ratio of 25(OH)D:DBP, an estimate of unbound (free) 25(OH)D levels. We adjusted for smoking (status and pack-years), BMI, physical activity, education and (mutually) for 25(OH)D and DBP. Restricted cubic splines were employed to examine nonlinear associations. Results High optimal levels of circulating 25(OH)D (≥100 nmol/L) (HR 0.35, 95% CI 0.19–0.64) were associated with decreased BC risk, when compared with insufficient concentrations (50–74 nmol/L). This association was less pronounced for optimal levels (75–99 nmol/L) (HR = 0.69, 95% CI 0.47–1.01). Moreover, estimated free 25(OH)D, was associated with decreased BC risk for molar ratio 17–21 (HR 0.66, 95% CI 0.44–0.97) and ≥22 (HR 0.50, 95% CI 0.29–0.82), compared to molar ratio 11–16. The HR function for BC risk was not linear, rather reversed u-shaped, with the highest HR at 62.5 nmol/L and 13.5 molar ratio, respectively. Conclusion High levels of total and estimated free 25(OH)D were associated with reduced risk of BC, compared with insufficient concentrations. DBP was not associated with BC risk. We did not observe any impact of DBP or any of the studied lifestyle factors on the association between 25(OH)D and BC.

• Karlsen, Jarle; Tandstad, Torgrim; Sowa, Piotr; Salvesen, Øyvind; Stenehjem, Jo S. & Lundgren, Steinar [Show all 7 contributors for this article] (2021). Pneumonitis and fibrosis after breast cancer radiotherapy: occurrence and treatment-related predictors. Acta Oncologica. ISSN 0284-186X. doi: 10.1080/0284186X.2021.1976828. Full text in Research Archive Show summary

  Background Radiation pneumonitis (RP) and radiation fibrosis (RF) are common side effects after breast cancer (BC) radiotherapy (RT). However, there is a great variation in the frequency of RP and RF. This study presents the occurrence of- and the treatment-related predictors for RP and RF. Further, physician- and patient-reported pulmonary symptoms during the first year after postoperative RT for BC are demonstrated. Materials and methods From 2007 to 2008, 250 BC patients referred for postoperative RT were included in a prospective cohort study and followed during the first year after RT. High-resolution computed tomography of the lungs and symptom registration were performed before RT and 3, 6, and 12 months after RT. Patient-reported symptoms were registered by standard quality of life questionnaires. Logistic regression analyses were applied to estimate treatment-related predictors for radiological RP (rRP), clinical RP (cRP), radiological RF (rRF), and clinical RF (cRF). Results The occurrence of rRP and cRP at three months was 78% and 19%, while 12 months after RT rRF and cRF was 89% and 16%, respectively; all reported as grade 1. In multivariable analyses, mastectomy predicted cRP at three months (OR = 2.48, p = .03) and cRF at six months, ipsilateral lung volume receiving 20 Gray or more (V20), V30, and mean lung dose (MLD) predicted rRP at six months (OR = 1.06, p = .0003; OR = 1.10, p = .001; and OR = 1.03, p = .01, respectively). Endocrine treatment predicted cRF at 12 months (OR = 2.48, p = .02). Physicians reported significant more dyspnea at 3 months (p = .003) and patients reported ‘a little dyspnea’ more at 3 and 12 months compared to baseline (p = .007). Conclusion RP and RF are prevalent in the first year after BC radiation. Mastectomy predicted cRP at three months. V20, V30, D25, and MLD predicted rRP at 6 months, and endocrine treatment predicted cRF at 12 months. Patients and physicians reported dyspnea differently.

• Hektoen, Helga; Gislefoss, Randi Elin; Stenehjem, Jo S.; Langseth, Hilde; Axcrona, Karol & Mondul, Alison M. [Show all 8 contributors for this article] (2021). Prediagnostic serum 25-hydroxyvitamin d and mortality among bladder cancer patients in the janus serum bank cohort. Clinical Epidemiology. 13, p. 801–811. doi: 10.2147/CLEP.S319620. Full text in Research Archive
• Stenehjem, Jo Steinson; Røise, Olav; Nordseth, Trond; Clausen, Thomas; Natvig, Bård & Skurtveit, Svetlana Ondrasova [Show all 10 contributors for this article] (2021). Injury Prevention and long-term Outcomes following Trauma - The IPOT project: a protocol for prospective nationwide registry-based studies in Norway. BMJ Open. 11(5). doi: 10.1136/bmjopen-2020-046954. Full text in Research Archive Show summary

  Introduction Traumatic injuries constitute a major cause of mortality and morbidity. Still, the public health burden of trauma in Norway has not been characterised using nationwide registry data. More knowledge is warranted on trauma risk factors and the long-term outcomes following trauma. The Injury Prevention and long-term Outcomes following Trauma project will establish a comprehensive research database. The Norwegian National Trauma Registry (NTR) will be merged with several data sources to pursue the following three main research topics: (1) the public health burden of trauma to society (eg, excess mortality and disability-adjusted life-years (DALYs)), (2) trauma aetiology (eg, socioeconomic factors, comorbidity and drug use) and (3) trauma survivorship (eg, survival, drug use, use of welfare benefits, work ability, education and income). Methods and analysis The NTR (n≈27 000 trauma patients, 2015–2018) will be coupled with the data from Statistics Norway, the Norwegian Patient Registry, the Cause of Death Registry, the Registry of Primary Health Care and the Norwegian Prescription Database. To quantify the public health burden, DALYs will be calculated from the NTR. To address trauma aetiology, we will conduct nested case–control studies with 10 trauma-free controls (drawn from the National Population Register) matched to each trauma case on birth year, sex and index date. Conditional logistic regression models will be used to estimate trauma risk according to relevant exposures. To address trauma survivorship, we will use cohort and matched cohort designs and time-to-event analyses to examine various post-trauma outcomes.

• Berge, Leon Alexander; Kulle, Bettina; Stenehjem, Jo S.; Heir, Trond; Furu, Kari & Juzeniene, Asta [Show all 11 contributors for this article] (2020). Use of Antidepressants and Risk of Cutaneous Melanoma: A Prospective Registry-Based Case-Control Study. Clinical Epidemiology. 12, p. 193–202. doi: 10.2147/CLEP.S241249. Full text in Research Archive Show summary

  Purpose: Melanoma is the cancer with the most rapidly rising incidence rate in Norway. Although exposure to ultraviolet radiation (UVR) is the major environmental risk factor, other factors may also contribute. Antidepressants have cancer inhibiting and promoting side effects, and their prescription rates have increased in parallel with melanoma incidence. Thus, we aimed to prospectively examine the association between use of antidepressants and melanoma by using nation-wide data from the Cancer Registry of Norway, the National Registry, the Norwegian Prescription Database and the Medical Birth Registry of Norway. Patient and Methods: All cases aged 18– 85 with a primary cutaneous invasive melanoma diagnosed during 2007– 2015 (n=12,099) were matched to population controls 1:10 (n=118,467) by sex and year of birth using risk-set sampling. We obtained information on prescribed antidepressants and other potentially confounding drug use (2004– 2015). Conditional logistic regression was used to estimate adjusted rate ratios (RRs) and 95% confidence intervals (CIs) for the association between overall and class-specific use of antidepressants and incident melanoma. Results: Compared with ≤ 1 prescription, ≥ 8 prescriptions of antidepressants overall were negatively associated with melanoma (RR 0.81 CI 0.75– 0.87). Class-specific analyses showed decreased RRs for selective serotonin reuptake inhibitors (RR 0.82 CI 0.73– 0.93) and mixed antidepressants (RR 0.77 CI 0.69– 0.86). The negative association was found for both sexes, age ≥ 50 years, residential regions with medium and highest ambient UVR exposure, all histological subtypes, trunk, upper and lower limb sites and local disease. Conclusion: Use of antidepressants was associated with decreased risk of melanoma. There are at least two possible explanations for our results; cancer-inhibiting actions induced by the drug and less UVR exposure among the most frequent users of antidepressants.

• Stenehjem, Jo S.; Støer, Nathalie Charlotte; Ghiasvand, Reza; Grimsrud, Tom Kristian; Babigumira, Ronnie & Rees, Judy R. [Show all 11 contributors for this article] (2020). Prediagnostic serum 25-hydroxyvitamin D and melanoma risk. Scientific Reports. 10, p. 1–11. doi: 10.1038/s41598-020-77155-2. Full text in Research Archive Show summary

  Abstract Previous studies of serum 25-hydroxyvitamin D (25(OH)D) in relation to melanoma have shown conflicting results. We conducted a nested case–control study of 708 cases and 708 controls, using prediagnostically collected serum, to study 25(OH)D and melanoma risk in the population-based Janus Serum Bank Cohort. Stratified Cox regression was used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs) adjusted for ultraviolet radiation (UVR) indicators and stratified by ambient UVB of residence and body mass index (BMI). Non-linear associations were studied by restricted cubic splines. Missing data were handled with multiple imputation by chained equations. We found an HR of melanoma risk of 1.01 (95% CI: 0.99, 1.04) and an HR imputed of 1.02 (95% CI: 1.00, 1.04) per 5-nmol/L increase. The spline model showed exposure-risk curves with significantly reduced melanoma risk between 60 and 85 nmol/L 25(OH)D (reference 50 nmol/L). Non-significant J-shaped curves were found in sub-analyses of subjects with high ambient UVB of residence and of subjects with BMI &lt; 25 kg/m 2 . Our data did not yield persuasive evidence for an association between 25(OH)D and melanoma risk overall. Serum levels within the medium range might be associated with reduced risk, an association possibly mediated by BMI.

• Svendsen, Karianne; Langslet, Gisle; Krogh, Henriette Walaas; Brinck, Jonas; Stenehjem, Jo S. & Holven, Kirsten Bjørklund [Show all 8 contributors for this article] (2020). Genetic testing is essential for initiating statin therapy in children with familial hypercholesterolemia: Examples from Scandinavia. Atherosclerosis. ISSN 0021-9150. 316, p. 48–52. doi: 10.1016/j.atherosclerosis.2020.11.027. Full text in Research Archive Show summary

  Background and aims In familial hypercholesterolemia (FH), statin treatment should be considered from 8 to 10 years of age, but the prevalence of statin use among children is not known. Methods Statin use (2008–2018) among children aged 10–14 and 15–19 years was obtained from the national prescription databases in Norway, Sweden and Denmark. We assumed that all statin users in these age groups had FH, and that the estimated prevalence of FH is 1 in 250 inhabitants. Changes in prevalence rates of statin use between 2008 and 2018 by country, age and sex were estimated using the Joinpoint Regression Program version 4.8.0.1. Differences in prevalence rate ratio each year between countries were analyzed using Poisson regression. Results Among children aged 10–14 years, there was a significant increase in statin use in Norway and Denmark between 2008 and 2018, while in Sweden an increase was only seen after 2014. Among children aged 15–19 years, an increase in statin use was only observed in Norway and Sweden between 2008 and 2018. Statin use was significantly more prevalent in Norway than in Sweden and Denmark each year, and in 2018 the proportion of children using statins was 4–5 times (10–14 years) and 3 times (15–19 years) higher in Norway compared with Sweden and Denmark. In 2018 in Norway, 19% and 35% of children aged 10–14 years and 15–19 years estimated to have FH used statins respectively; corresponding percentages in Sweden were 4.5% and 10%, and in Denmark 3% and 12%. In Norway, the increase in statin use between 2008 and 2018 roughly corresponded to the increase in children with genetically verified FH. Conclusions Between 2008 and 2018, statin use increased in children aged 10–19 years in Norway, Sweden and Denmark, but with large differences between the countries; statin use was 3–5 times more prevalent in Norway than in Sweden and Denmark, which may be due to a more widespread use of genetic testing for FH in Norway.

• Robsahm, Trude Eid; Stenehjem, Jo S.; Berge, Leon Alexander & Veierød, Marit Bragelien (2020). Prevalence of Indoor Tanning Among Teenagers in Norway Before and After Enforcement of Ban for Ages Under 18 Years. Acta Dermato-Venereologica. ISSN 0001-5555. 100(8). doi: 10.2340/00015555-3482. Full text in Research Archive
• Stenehjem, Jo S.; Babigumira, Ronnie; Hosgood, H Dean; Veierød, Marit Bragelien; Samuelsen, Sven Ove & Bråtveit, Magne [Show all 18 contributors for this article] (2020). Cohort Profile: The Norwegian Offshore Petroleum Workers (NOPW) Cohort. International Journal of Epidemiology. ISSN 0300-5771. 50(2). doi: 10.1093/ije/dyaa107. Full text in Research Archive
• Berge, Leon Alexander; Kulle, Bettina; Stenehjem, Jo S.; Heir, Trond; Karlstad, Øystein & Juzeniene, Asta [Show all 11 contributors for this article] (2020). Use of immunomodulating drugs and risk of cutaneous melanoma: A nationwide nested case-control study. Clinical Epidemiology. 12, p. 1389–1401. doi: 10.2147/CLEP.S269446. Full text in Research Archive Show summary

  Purpose: Cutaneous melanoma is among the fastest growing malignancies in Norway and ultraviolet radiation (UVR) exposure is the primary environmental risk factor. Immunomodulating drugs can increase skin photosensitivity and suppress immune responses, and by such mechanisms influence melanoma risk. We, therefore, aimed to examine the associations between use of immunomodulating drugs and melanoma risk, at a nationwide population level. Patients and Methods: In the Cancer Registry of Norway, we identified all cases aged 18– 85 with a first primary cutaneous melanoma diagnosed in 2007– 2015 (n=12,106). These were matched to population controls from the Norwegian National Registry 1:10 (n=118,564), on sex and year of birth using risk set sampling. Information on prescribed drugs (2004– 2015) was obtained by linkage to the Norwegian Prescription Database (NorPD). Conditional logistic regression was used to estimate rate ratios (RRs) and 95% confidence intervals (CIs) for associations between use of immunomodulating drugs (immunosuppressants and corticosteroids) and melanoma risk, adjusted for ambient UVR and other drug use. Results: Compared with ≤ 1 prescription, use of ≥ 8 prescriptions of immunosuppressants was associated with increased risk of melanoma (RR 1.50, 95% CI 1.27, 1.77). Similar associations were found for subgroups of immunosuppressants: drugs typically prescribed to organ transplant recipients (OTRs) (RR 2.02, 95% CI 1.35, 3.03) and methotrexate (RR 1.27, 95% CI 1.04, 1.55). Similar results were found for high levels of cumulative doses and across all histological subtypes. Use of corticosteroids was not associated with melanoma risk. Conclusion: We found a positive association between use of immunosuppressants and melanoma risk, with the highest risk seen for drugs prescribed to OTRs. Knowledge about this risk increase is important for physicians and users of these drugs, for intensified surveillance, awareness and cautious sun exposure.

• Hektoen, Helga; Robsahm, Trude Eid; Kulle, Bettina; Stenehjem, Jo S.; Axcrona, Karol & Mondul, Alison [Show all 7 contributors for this article] (2020). Lifestyle associated factors and risk of urinary bladder cancer: A prospective cohort study from Norway. Cancer Medicine. 9(12), p. 4420–4432. doi: 10.1002/cam4.3060. Full text in Research Archive Show summary

  A number of lifestyle associated factors, such as high body mass index (BMI), low physical activity, and related metabolic disorders, are associated with increased risk of cancer at several sites. For urinary bladder cancer (BC), such studies show inconsistent results, which could result from inadequate adjustment for smoking and occupational exposure. In the population‐based Janus Cohort (n = 292 851), we investigated the independent and combined impact of BMI, physical activity, blood pressure, and blood lipids on the risk of BC, by thorough adjustment for smoking and potential occupational exposure. We used cox proportional hazard regression to estimate hazard ratios (HRs) with 95% confidence intervals (CIs) for the associations between the lifestyle associated factors and BC risk. The associations observed were dependent on smoking status and gender. Among men, diastolic blood pressure (DBP) (HR 1.07, 95% CI 1.02‐1.12) and systolic blood pressure (SBP) (HR 1.04, 95% CI 1.01‐1.07) were positively associated with BC risk. Stratification by smoking status revealed a positive association between DBP and BC risk in never smokers (HR 1.14, 95% CI 1.00‐1.30), while no association was seen for current and former smokers. A risk score, integrating information across the lifestyle factors was positively associated with BC risk in men (ptrend = 0.043). In women, physical activity was associated with a decreased BC risk, but only among never smokers (HR 0.65, 95% CI 0.45‐0.94). In conclusion, relations between lifestyle associated factors and BC risk were most evident in never smokers, suggesting that smoking dominates the relation in current smokers.

• Rueegg, Corina Silvia; Stenehjem, Jo S.; Egger, Matthias; Ghiasvand, Reza; Cho, Eunyoung & Lund, Eiliv [Show all 9 contributors for this article] (2019). Challenges in assessing the sunscreen-melanoma association. International Journal of Cancer. ISSN 0020-7136. 144, p. 2651–2668. doi: 10.1002/ijc.31997. Full text in Research Archive Show summary

  Whether sunscreen use affects melanoma risk has been widely studied with contradictory results. To answer this question we performed a systematic review of all published studies, accounting for sources of heterogeneity and bias. We searched for original articles investigating the sunscreen‐melanoma association in humans to February 28, 2018. We then used random‐effects meta‐analysis to combine estimates of the association, stratified by study design. Stratified meta‐analysis and meta‐regression were used to identify sources of heterogeneity. We included 21,069 melanoma cases from 28 studies published 1979–2018: 23 case–control (11 hospital‐based, 12 population‐based), 1 ecological, 3 cohort and 1 randomised controlled trial (RCT). There was marked heterogeneity across study designs and among case–control studies but adjustment for confounding by sun exposure, sunburns and phenotype systematically moved estimates toward decreased melanoma risk among sunscreen users. Ever‐ vs. never‐use of sunscreen was inversely associated with melanoma in hospital‐based case–control studies (adjusted odds ratio (OR) = 0.57, 95%confidence interval (CI) 0.37–0.87, <i>P</i>_{heterogeneity} < 0.001), the ecological study (rate ratio = 0.48, 95%CI 0.35–0.66), and the RCT (hazard ratio (HR) = 0.49, 95%CI 0.24–1.01). It was not associated in population‐based case–control studies (OR = 1.17, 95%CI 0.90–1.51, <i>P</i>_{heterogeneity} < 0.001) and was positively associated in the cohort studies (HR = 1.27, 95%CI 1.07–1.51, <i>P</i>_{heterogeneity} = 0.236). The association differed by latitude (<i>P</i>_interaction = 0.042), region (<i>P</i>_interaction = 0.008), adjustment for naevi/freckling (<i>P</i>_interaction = 0.035), and proportion of never‐sunscreen‐users (<i>P</i>_interaction = 0·012). Evidence from observational studies on sunscreen use and melanoma risk was weak and heterogeneous, consistent with the challenges of controlling for innate confounding by indication. The only RCT showed a protective effect of sunscreen.

• Stenehjem, Jo S.; Babigumira, Ronnie; Friesen, Melissa C. & Grimsrud, Tom Kristian (2019). Harmonizing work history data in epidemiologic studies with overlapping employment records. American Journal of Industrial Medicine. ISSN 0271-3586. 62(5), p. 422–429. doi: 10.1002/ajim.22965. Full text in Research Archive Show summary

  Background Work history data often require major data management including handling of overlapping jobs to avoid overestimating exposure before linkage to job‐exposure matrices (JEMs) is possible. Methods In a case‐cohort study of 1825 male Norwegian offshore petroleum workers, 3979 jobs were reported (mean duration 2417 days/job; maximum 8 jobs/worker). Each job was assigned to one of 27 occupation categories. Overlapping jobs of the same category (1142 jobs) were collapsed and overlapping jobs of different categories (1013 jobs) were split. The resulting durations were weighted by a factor accounting for the number of overlapping jobs. Results Collapsing overlapping jobs within the same category resulted in 3295 jobs (mean 2629 days/job). Splitting overlapping jobs of different categories increased the number to 4239 jobs (mean 2043 days/job), while the total duration in days dropped by 10%. Conclusions We demonstrated that overlapping employment data structures can be harmonized in a systematic and unbiased way, preparing work history data for linkage to several JEMs.

• Berge, Leon Alexander; Kulle, Bettina; Stenehjem, Jo S.; Larsen, Inger Kristin; Furu, Kari & Juzeniene, Asta [Show all 11 contributors for this article] (2019). Cardiovascular, antidepressant and immunosuppressive drug use in relation to risk of cutaneous melanoma: A protocol for a prospective case-control study. BMJ Open. 9:e025246(2), p. 1–8. doi: 10.1136/bmjopen-2018-025246. Full text in Research Archive Show summary

  The incidence of cutaneous melanoma (hereafter melanoma) has increased dramatically among fair-skinned populations worldwide. In Norway, melanoma is the most rapidly growing type of cancer, with a 47% increase among women and 57% among men in 2000–2016. Intermittent ultraviolet exposure early in life and phenotypic characteristics like a fair complexion, freckles and nevi are established risk factors, yet the aetiology of melanoma is multifactorial. Certain prescription drugs may have carcinogenic side effects on the risk of melanoma. Some cardiovascular, antidepressant and immunosuppressive drugs can influence certain biological processes that modulate photosensitivity and immunoregulation. We aim to study whether these drugs are related to melanoma risk.Methods and analysisA population-based matched case–control study will be conducted using nation-wide registry data. Cases will consist of all first primary, histologically verified melanoma cases diagnosed between 2007 and 2015 identified in the Cancer Registry of Norway (14 000 cases). Ten melanoma-free controls per case (on date of case melanoma diagnosis) will be matched based on sex and year of birth from the National Registry of Norway. For the period 2004—2015, and by using the unique personal identification numbers assigned to all Norwegian citizens, the case–control data set will be linked to the Norwegian Prescription Database for information on drugs dispensed prior to the melanoma diagnosis, and to the Medical Birth Registry of Norway for data regarding the number of child births. Conditional logistic regression will be used to estimate associations between drug use and melanoma risk, taking potential confounding factors into account.Ethics and disseminationThe project is approved by the Regional Committee for Medical Research Ethics in Norway and by the Norwegian Data Protection Authority. The study is funded by the Southeastern Norway Regional Health Authority. Results will be published in peer-reviewed journals and disseminated further through scientific conferences, news media and relevant patient interest groups.

• Gislefoss, Randi Elin; Stenehjem, Jo S.; Hektoen, Helga; Kulle, Bettina; Langseth, Hilde & Axcrona, Karol [Show all 9 contributors for this article] (2018). Vitamin D, obesity and leptin in relation to bladder cancer incidence and survival: Prospective protocol study. BMJ Open. 8:e019309(3), p. 1–6. doi: 10.1136/bmjopen-2017-019309. Full text in Research Archive
• Stenehjem, Jo Steinson; Veierød, Marit Bragelien; Nilsen, Lill Tove Norvang; Ghiasvand, Reza; Johnsen, Bjørn J & Grimsrud, Tom Kristian [Show all 10 contributors for this article] (2018). Anthropometric factors and Breslow thickness: prospective data on 2570 cases of cutaneous melanoma in the population-based Janus Cohort. British Journal of Dermatology. ISSN 0007-0963. 179(3), p. 632–641. doi: 10.1111/bjd.16825. Full text in Research Archive Show summary

  Background Breslow thickness is the most important prognostic factor of localized cutaneous melanoma (CM), but associations with anthropometric factors have been sparsely and incompletely investigated. Objectives To examine prediagnostic body mass index (BMI), body surface area (BSA), and height, weight and weight change in relation to Breslow thickness, overall and by anatomical site and histological subtype; and to assess possible nonlinear associations between these anthropometric factors and Breslow thickness. Methods CMs in the Janus Cohort were identified between 1972 and 2014. Linear regression was used to estimate geometric mean ratios (GMRs) of Breslow thickness with 95% confidence intervals (CIs) according to anthropometric factors. Restricted cubic splines in generalized linear models predicted adjusted mean Breslow thickness, and were used to assess possible nonlinear relationships. Results Of 2570 cases of CM, obese patients had a GMR of 1·16 (95% CI 1·04–1·30) of Breslow thickness vs. normal‐weight patients. For BSA and weight, quintile 5 showed GMRs of 1·13 (95% CI 1·00–1·27) and 1·17 (95% CI 1·03–1·33) of Breslow thickness vs. quintile 1, respectively. Associations seemed restricted to superficial spreading melanomas and CMs on the trunk and lower limbs. The associations plateaued at an adjusted mean Breslow thickness of about 2·5 mm (BMI 29 kg m−2, BSA 2·05 m2 and weight 90 kg), before declining for the highest values. No associations were found for height and weight change. Conclusions This large case‐series of incident CM demonstrated positive associations between BMI, BSA, weight and Breslow thickness, and suggested that behavioural or other mechanisms apply at high values. This is the peer reviewed version of the article, which has been published in final form at Wiley. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions."

• Stenehjem, Jo Steinson; Veierød, Marit Bragelien; Nilsen, Lill Tove N; Ghiasvand, Reza; Johnsen, Bjørn & Grimsrud, Tom Kristian [Show all 9 contributors for this article] (2018). Anthropometric factors and cutaneous melanoma: Prospective data from the population-based Janus Cohort. International Journal of Cancer. ISSN 0020-7136. 142(4), p. 681–690. doi: 10.1002/ijc.31086. Full text in Research Archive Show summary

  The aim of the present study was to prospectively examine risk of cutaneous melanoma (CM) according to measured anthropometric factors, adjusted for exposure to ultraviolet radiation (UVR), in a large population‐based cohort in Norway. The Janus Cohort, including 292,851 Norwegians recruited 1972–2003, was linked to the Cancer Registry of Norway and followed for CM through 2014. Cox regression was used to estimate hazard ratios (HRs) of CM with 95% confidence intervals (CIs). Restricted cubic splines were incorporated into the Cox models to assess possible non‐linear relationships. All analyses were adjusted for attained age, indicators of UVR exposure, education, and smoking status. During a mean follow‐up of 27 years, 3,000 incident CM cases were identified. In men, CM risk was positively associated with body mass index, body surface area (BSA), height and weight (all ptrends < 0.001), and the exposure‐response curves indicated an exponential increase in risk for all anthropometric factors. Weight loss of more than 2 kg in men was associated with a 53% lower risk (HR 0.47, 95% CI: 0.39, 0.57). In women, CM risk increased with increasing BSA (ptrend = 0.002) and height (ptrend < 0.001). The shape of the height‐CM risk curve indicated an exponential increase. Our study suggests that large body size, in general, is a CM risk factor in men, and is the first to report that weight loss may reduce the risk of CM among men. This is the peer reviewed version of the article, which has been published in final form at Wiley. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.

• Stenehjem, Jo Steinson; Vik, Kirsti Lund & Nilsen, Tom Ivar Lund (2018). Adiposity, physical activity, and risk of hypertension: Prospective data from the population-based HUNT Study, Norway. Journal of Human Hypertension. ISSN 0950-9240. 32(4), p. 278–286. doi: 10.1038/s41371-018-0042-5. Full text in Research Archive
• Stenehjem, Jo Steinson; Smeland, Knut Bjøro; Murbræch, Klaus; Holte, Harald; Kvaløy, Stein Olav & Wethal, Torgeir [Show all 8 contributors for this article] (2018). Obstructive and restrictive pulmonary dysfunction in long-term lymphoma survivors after high-dose therapy with autologous stem cell transplantation. Acta Oncologica. ISSN 0284-186X. 57(6), p. 773–781. doi: 10.1080/0284186X.2017.1406137. Full text in Research Archive Show summary

  Background: Obstructive and restrictive dysfunction in long-term lymphoma survivors (LSs) after high-dose therapy with autologous stem-cell transplantation (HDT-ASCT) has not been addressed systematically previously. Material and methods: LSs treated in Norway 1987–2008 with HDT-ASCT who performed spirometry, measurement of static lung volumes and echocardiography 2012–2014 at either Oslo or St. Olavs University Hospitals was eligible. Smoking data were recorded by questionnaire. Treatment data were collected from medical records or hospital databases. Factors associated with obstructive and restrictive impairments (dichotomous outcomes) were examined by Poisson regression. Linear regression with the margins post-estimation command was used to derive adjusted mean values of forced expiratory volume in 1 s (FEV1). We used the normative reference data recommended by the European Respiratory Society for calculating percent predicted values. Results: A total of 226 LSs were studied, of whom 11.5 and 5.8% had obstructive and restrictive impairment, respectively. For women and men, mean FEV1 was 2.31 and 3.34 l corresponding to 11.4%- and 11.1%-points below that predicted from norms, respectively. In multivariable regression analyses, cumulative doxorubicin dose (400–775 mg/m2) and current smoking were associated with increased risk of obstructive impairment, and chest RT (>13–66 Gy) was associated with increased risk of restrictive impairment. Currently smoking LSs within the highest doxorubicin category (400–775 mg/m2), had the lowest adjusted mean FEV1. Conclusions: Despite intensive cancer treatment, our analysis showed modest reductions in obstructive parameters among long-term LSs after HDT-ASCT compared to normative reference data. To limit obstructive impairments in LSs after HDT-ASCT, we suggest that targeted smoking-cessation advice is directed towards patients who have received high cumulative doses of doxorubicin.

• Smeland, Knut Bjøro; Loge, Jon Håvard; Aass, Hans Christian Dalsbotten; Aspelin, Trude; Bersvendsen, Hanne Skjerven & Bolstad, Nils [Show all 16 contributors for this article] (2018). Chronic fatigue is highly prevalent in survivors of autologous stem cell transplantation and associated with IL-6, neuroticism, cardiorespiratory fitness, and obesity. Bone Marrow Transplantation. ISSN 0268-3369. p. 1–4. doi: 10.1038/s41409-018-0342-y. Full text in Research Archive
• Stenehjem, Jo Steinson; Robsahm, Trude Eid; Bråtveit, Magne; Samuelsen, Sven Ove; Kirkeleit, Jorunn & Grimsrud, Tom Kristian (2017). Aromatic hydrocarbons and risk of skin cancer by anatomical site in 25 000 male offshore petroleum workers. American Journal of Industrial Medicine. ISSN 0271-3586. 60(8), p. 679–688. doi: 10.1002/ajim.22741. Full text in Research Archive Show summary

  Background: We prospectively examined skin cancer risk according to occupational exposure to aromatic hydrocarbons with adjustment for ultraviolet radiation exposure, in a cohort of 24 917 male offshore petroleum workers. Methods: Hazard ratios (HRs) and 95% confidence intervals were estimated with Cox regression adapted to a stratified case‐cohort design. Results: During 13.5 years of follow‐up, 112 cutaneous melanomas (CMs) and 70 non‐melanoma skin cancers were identified. Increased risks of CM and of squamous cell carcinoma on the forearm and hand were seen among those ever exposed to crude oil or benzene. For skin cancers of the forearm and hand combined, cumulative and duration metrics of benzene exposure showed Ptrends of 0.031 and 0.003, respectively. Conclusions: Our results support an association between exposure to crude oil or benzene and skin cancer risk on hands and forearms among offshore petroleum workers. Dermal uptake of polycyclic aromatic hydrocarbons or benzene may explain this association. This research has been published in the American Journal of Industrial Medicine. © 2017 Wiley

• Stenehjem, Jo Steinson; Grimsrud, Tom Kristian; Rees, Judith R.; Vos, Linda; Babigumira, Ronnie & Veierød, Marit Bragelien [Show all 7 contributors for this article] (2017). A protocol for prospective studies of 25-hydroxyvitamin D, leptin and body mass index in relation to cutaneous melanoma incidence and survival. BMJ Open. 7(6). doi: 10.1136/bmjopen-2016-014829. Full text in Research Archive
• Vik, Kirsti Lund; Stenehjem, Jo Steinson & Nilsen, Tom Ivar Lund (2017). Adiposity, physical activity and risk of diabetes mellitus: Prospective data from the population-based HUNT study, Norway. BMJ Open. 7(1). doi: 10.1136/bmjopen-2016-013142. Full text in Research Archive Show summary

  Background Physical activity may counteract the adverse effects of adiposity on cardiovascular mortality; however, the evidence of a similar effect on diabetes is sparse. This study examines whether physical activity may compensate for the adverse effect of adiposity on diabetes risk. Methods The study population consisted of 38 231 individuals aged 20 years or more who participated in two consecutive waves of the prospective longitudinal Nord-Trøndelag Health Study in Norway: in 1984–1986 and in 1995–1997. A Poisson regression model with SEs derived from robust variance was used to estimate adjusted risk ratios of diabetes between categories of body mass index and physical activity. Results Risk of diabetes increased both with increasing body mass (Ptrend <0.001) and with decreasing physical activity level (Ptrend <0.001 in men and 0.01 in women). Combined analyses showed that men who were both obese and had low activity levels had a risk ratio of 17 (95% CI 9.52 to 30) compared to men who were normal weight and highly active, whereas obese men who reported high activity had a risk ratio of 13 (95% CI 6.92 to 26). Corresponding analysis in obese women produced risk ratios of 15 (95% CI 9.18 to 25) and 13 (95% CI 7.42 to 21) among women reporting low and high activity levels, respectively. Conclusions This study shows that overweight and obesity are associated with a substantially increased risk of diabetes, particularly among those who also reported being physically inactive. High levels of physical activity were associated with a lower risk of diabetes within all categories of body mass index, but there was no clear evidence that being physically active could entirely compensate for the adverse effect of adiposity on diabetes risk.

• Stenehjem, Jo Steinson; Robsahm, Trude Eid; Bråtveit, Magne; Samuelsen, Sven Ove; Kirkeleit, Jorunn & Grimsrud, Tom Kristian (2017). Ultraviolet radiation and skin cancer risk in offshore workers. Occupational Medicine. ISSN 0962-7480. 67(7), p. 569–573. doi: 10.1093/occmed/kqx110. Full text in Research Archive Show summary

  Background: Excess skin cancer mortality and incidence have been reported among both land-based and offshore petroleum workers. The association between skin cancer and ultraviolet radiation (UVR) exposure has not been examined in these workers, although they have long off-duty periods and high average income that may allow travelling to sunny destinations. In addition, they have access to solariums free of charge on many accommodation platforms. Aims: To prospectively examine risk of incident cutaneous melanoma (CM) and non-melanoma skin cancer (NMSC), according to sun-tanning habits with adjustment for aromatic hydrocarbon exposure. Methods: A cohort of men employed offshore from 1965 to 1999 was linked through the Cancer Registry of Norway 1999–2012. Cox regression adapted to a stratified case-cohort design was used to estimate hazard ratios with 95% confidence intervals. Results: The cohort included 24917 men. During 13.5 years of follow-up, 112 CMs and 70 NMSCs occurred. A positive dose–response relationship was seen between sunburn frequency and risk of CM (Ptrend < 0.05) and NMSC (Ptrend < 0.01). Solarium use both before and after age 20 was related to increased risk of NMSC. Sunscreen use was associated with increased risk of NMSC (Ptrend < 0.001). Conclusions: UVR exposure seems to be a significant contributor to the elevated risk of skin cancer observed in North Sea offshore workers. The positive association between solarium use and NMSC risk adds to the growing body of literature on artificial UV devices as carcinogenic. This research has been published in Occupational Medicine. © 2017 Oxford University Press

• Stenehjem, Jo Steinson; Smeland, Knut Bjøro; Murbræch, Klaus; Holte, Harald; Kvaløy, Stein Olav & Thorsen, Lene [Show all 11 contributors for this article] (2016). Cardiorespiratory fitness in long-term lymphoma survivors after high-dose chemotherapy with autologous stem cell transplantation. British Journal of Cancer. ISSN 0007-0920. 115(2), p. 178–187. doi: 10.1038/bjc.2016.180. Full text in Research Archive
• Stenehjem, Jo Steinson; Kjærheim, Kristina; Bråtveit, Magne; Samuelsen, Sven Ove; Barone-Adesi, Francesco & Rothman, Nathaniel [Show all 8 contributors for this article] (2015). Benzene exposure and risk of lymphohaematopoietic cancers in 25 000 offshore oil industry workers. British Journal of Cancer. ISSN 0007-0920. 112(9), p. 1603–1612. doi: 10.1038/bjc.2015.108. Full text in Research Archive Show summary

  Background: The aim of this work was to examine the risk of lymphohaematopoietic (LH) cancer according to benzene exposure among offshore workers. Methods: Cancer registry data were used to identify 112 cancer cases diagnosed during 1999–2011 in a cohort of 24 917 Norwegian men reporting offshore work between 1965 and 1999. Analyses were conducted according to a stratified case–cohort design with a reference subcohort of 1661 workers. Cox regression was used to estimate hazard ratios with 95% confidence intervals, adjusted for other benzene exposure and smoking. Results: Most workers were exposed to benzene for <15 years. The upper range values of average intensity and cumulative exposure were estimated to 0.040 p.p.m. and 0.948 p.p.m.-years, respectively. Risks were consistently elevated among exposed workers for all LH cancers combined and for most subgroups, although case numbers were small and yielded imprecise risk estimates. There was evidence of dose-related risk patterns according to cumulative exposure for acute myeloid leukaemia (AML), multiple myeloma (MM) (P trends 0.052 and 0.024, respectively), and suggestively so for chronic lymphocytic leukaemia (CLL) according to average intensity (P trend 0.094). Conclusions: Our results support an association between cumulative and intensity metrics of low-level benzene exposure and risk for AML, MM, and suggestively for CLL.

• Stenehjem, Jo Steinson; Friesen, Melissa C.; Eggen, Tone; Kjærheim, Kristina; Bråtveit, Magne & Grimsrud, Tom Kristian (2015). Self-reported occupational exposures relevant for cancer among 28,000 Offshore oil industry workers employed between 1965 and 1999. Journal of Occupational and Environmental Hygiene. ISSN 1545-9624. 12(7), p. 458–468. doi: 10.1080/15459624.2014.989358. Full text in Research Archive
• Stenehjem, Jo Steinson; Kjærheim, Kristina; Rabanal, Kjersti Stormark & Grimsrud, Tom Kristian (2014). Cancer incidence among 41000 offshore oil industry workers. Occupational Medicine. ISSN 0962-7480. 64(7), p. 539–545. doi: 10.1093/occmed/kqu111. Full text in Research Archive

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• Perrier, Flavie; Rimal, Raju; Green, Adele C; Rueegg, Corina Silvia; Ghiasvand, Reza & Gjersvik, Petter [Show all 13 contributors for this article] (2026). Breslow thickness and melanoma-specific death in patients diagnosed with thin cutaneous melanoma in 1983-2019. Full text in Research Archive
• Marjerrison, Niki; Grimsrud, Tom Kristian; Hansen, Johnni; Martinsen, Jan Ivar; Nordby, Karl-Christian & Olsen, Raymond [Show all 9 contributors for this article] (2025). Occupational exposures of firefighting and prostate cancer risk in the Norwegian fire departments cohort. Occupational and Environmental Medicine. ISSN 1351-0711. 82(Suppl. 1). doi: 10.1136/oemed-2024-epicohabstracts.3. Full text in Research Archive Show summary

  Objectives: In their 2022 classification of firefighting as carcinogenic, the International Agency for Research on Cancer deemed the evidence of the association with prostate cancer (PC) ‘limited’, citing an inability to rule out that a medical surveillance bias fully explained firefighters’ excess PC incidence compared to the general population. Our aim was to compare PC risk within a firefighter cohort, applying indicators of exposures. Methods: We used employment duration and the indicators fire exposure score, inhalation score and diesel exhaust exposure score to examine PC risk among men in the Norwegian Fire Departments Cohort (n=4251). Incident PC cases, including clinical characteristics, were obtained from the Cancer Registry of Norway (1960–2021). Cox regression was used to estimate hazard ratios (HRs) by cumulative exposure in tertiles (reference: lowest) for all, aggressive, and indolent PCs, with adjustment for age and birth cohort. The cumulative incidence of PC across birth cohorts and diagnostic periods was examined. Results: During 123,835 person-years of follow-up, there were 268 PC cases (61 aggressive, 69 indolent, 138 unclassifiable). No clear associations emerged for any of the exposure indicators, although elevated HRs were observed for aggressive PCs in the highest tertile of fire exposure score compared to the lowest (1.51, 95% CI 0.63–2.72), and for indolent PCs in the highest tertile of inhalation score compared to the lowest (1.31, 95% CI 0.60–2.89). Assessment of cumulative incidence by stage demonstrated a greater number of diagnoses of indolent and unclassifiable PC at younger ages from 1990. Conclusions: We did not observe clear associations between our exposure indicators and PC risk. However, our study had few cases in analyses by clinical stage. Studies of PC risk among firefighters remain challenged by difficulties in exposure characterization and a limited understanding of PC etiology, as well as the unclear magnitude of a medical surveillance bias. Funding: This work was funded by the Foundation Dam (grant no: 2019/FO247424), Cancer Society of Norway, Norwegian Firefighters Fight Cancer, Norwegian Union of Municipal and General Employees, Norwegian Union of Marine Engineers, and the Fire Union in Delta. Acknowledgements: We wish to thank Jarle Jakobsen (Nordland Hospital, Bodø, Norway) for his work in the early stages of this study. We also wish to thank the fire departments that collected and shared their data that constitutes the Norwegian Fire Departments Cohort, as well as our project reference group (comprising representatives from firefighters’ unions, employers’ organisations, the volunteer organisation ‘Norwegian Firefighters Fighting Cancer’, the Norwegian Directorate for Civil Protection, the Norwegian Labour Inspection Authority, and the Norwegian Cancer Society) for their contributions to the project.

• Andersen, Nina Gjerde; Azulay, Naomi; Nordseth, Trond; Rosseland, Leiv Arne; Stenehjem, Jo & Uleberg, Oddvar (2024). The Injury Preventiona and Outcomes following Trauma Project: A population-based analysis of return to work after trauma. Full text in Research Archive
• Stenehjem, Jo Steinson; Grimsrud, Tom Kristian & Veierød, Marit Bragelien (2022). Vi kan fortsatt lære av Kielland-ulykken. Full text in Research Archive
• Rasmussen, Anders; Stenehjem, Jo Steinson; Røise, Olav; Gran, Jon Michael; Kristiansen, Thomas & Uleberg, Oddvar [Show all 8 contributors for this article] (2022). Standardised mortality rates for non-traumatic deaths among survivors of trauma in Norway (2015-2018). Full text in Research Archive
• Uleberg, Oddvar; Kristiansen, Thomas; Nordseth, Trond; Stenehjem, Jo S.; Gran, Jon Michael & Clausen, Thomas [Show all 8 contributors for this article] (2022). Skader etter vold og ulykker - den glemte pandemi? 142(8), p. 678–679. doi: 10.4045/tidsskr.22.0261. Full text in Research Archive
• Uleberg, Oddvar; Stenehjem, Jo S.; Nordseth, Trond; Clausen, Thomas; Natvig, Bård & Skurtveit, Svetlana Ondrasova [Show all 12 contributors for this article] (2022). The injury prevention and outcomes following trauma (IPOT) project: is a nationwide registry-based study in Norway feasible? Full text in Research Archive
• Stenehjem, Jo S.; Røise, Olav; Nordseth, Trond; Clausen, Thomas; Natvig, Bård & Skurtveit, Svetlana Ondrasova [Show all 12 contributors for this article] (2021). Injury Prevention and long-term Outcomes following Trauma - the IPOT project: a protocol for prospective nationwide registry-based studies in Norway. Full text in Research Archive
• Rosseland, Leiv Arne; Stenehjem, Jo S.; Nordseth, Trond; Clausen, Thomas; Natvig, Bård & Skurtveit, Svetlana Ondrasova [Show all 12 contributors for this article] (2021). The Injury Prevention and Outcomes following Trauma project: a prospective nationwide registry-based study in Norway. Full text in Research Archive
• Liu, Fei-Chih; Veierød, Marit Bragelien; Kjærheim, Kristina; Robsahm, Trude Eid; Ghiasvand, Reza & Babigumira, Ronnie [Show all 11 contributors for this article] (2021). Excess risk of male breast cancer in the Norwegian Offshore Petroleum Workers (NOPW) cohort: a possible link to extreme night shift work? Breast Cancer Research. ISSN 1465-5411. doi: 10.1186/s13058-021-01485-w. Full text in Research Archive
• Nordseth, Trond; Stenehjem, Jo S.; Uleberg, Oddvar; Røise, Olav & Rosseland, Leiv Arne (2021). The Injury Prevention and Outcomes after Trauma project: differences in survival between health trusts. Full text in Research Archive
• Liu, Fei-Chih; Veierød, Marit B.; Kjærheim, Kristina; Robsahm, Trude E.; Ghiasvand, Reza & Babigumira, Ronnie [Show all 11 contributors for this article] (2021). Excess risk of male breast cancer in the Norwegian Offshore Petroleum Workers (NOPW) cohort: a possible link to extreme night shift work? Breast Cancer Research. ISSN 1465-5411. 23(1). doi: 10.1186/s13058-021-01485-w. Full text in Research Archive
• Andreassen, Bettina K.; Hektoen, Helga H.; Axcrona, Karol; Langseth, Hilde; Stenehjem, Jo S. & Robsahm, Trude E. (2021). Prediagnostic serum-25 hydroxyvitamin d and mortality among bladder cancer patients in the janus serum bank cohort: Answer to a short comment [response to letter]. Clinical Epidemiology. 13, p. 1061–1062. doi: 10.2147/CLEP.S345565. Full text in Research Archive
• Robsahm, Trude Eid; Stenehjem, Jo Steinson & Veierød, Marit Bragelien (2017). 18-årsgrensen for solariebruk skal håndheves :. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 137(9), p. 608–608. doi: 10.4045/tidsskr.17.0130. Full text in Research Archive
• Stenehjem, Jo Steinson; Smeland, Knut Bjøro; Murbraech, Klaus; Holte, Harald; Kvaløy, Stein Olav & Wethal, Torgeir [Show all 8 contributors for this article] (2017). Diffusing capacity impairment is prevalent in long-term lymphoma survivors after high-dose therapy with autologous stem cell transplantation. Bone Marrow Transplantation. ISSN 0268-3369. 52(4), p. 646–649. doi: 10.1038/bmt.2016.338. Full text in Research Archive
• Stenehjem, Jo Steinson; Smeland, Knut Bjøro; Murbræch, Klaus; Holte, Harald; Kvaløy, Stein Olav & Thorsen, Lene [Show all 9 contributors for this article] (2015). Exercise capacity in lymphoma survivors after high-dose chemotherapy with autologous stem cell transplantation: a national cross-sectional study. Norsk Epidemiologi, Supplement. ISSN 0803-4206. 25, p. 28–28. Full text in Research Archive
• Grimsrud, Tom Kristian; Stenehjem, Jo Steinson; Kjærheim, Kristina; Bråtveit, Magne; Samuelsen, Sven O & Barone-Adesi, Francesco [Show all 8 contributors for this article] (2014). Benzene Exposure and Risk of Lymphohematopoietic Cancers in 25,000 Offshore Oil Industry Workers. Full text in Research Archive
• Babigumira, Ronnie; Stenehjem, Jo; Veierød, Marit B. & Grimsrud, Tom Kristian (2026). Cohort Profiling, Data Harmonization and Epidemiological Analysis of Benzene Exposure and Cancer Risk in the Norwegian Offshore Petroleum Workers Cohort. Universitetet i Oslo. ISSN 9788234808708. Full text in Research Archive Show summary

  This thesis is situated within occupational cancer epidemiology and examines occupational exposures and cancer incidence among Norwegian offshore petroleum workers. It aimed to profile the Norwegian Offshore Petroleum Workers (NOPW) cohort and evaluate cancer incidence compared to the general population, harmonize work histories for exposure quantification, and examine associations between benzene exposure and risk of lung and colorectal cancer (CRC). The NOPW cohort comprises approximately 28,000 offshore petroleum workers who completed a survey containing information on work history, sociodemographic characteristics, and lifestyle factors. Cancer incidence was assessed through linkage with the Cancer Registry of Norway. To improve exposure assessment, a harmonization method was developed to address overlapping employment records before linkage to job exposure matrices. Associations between occupational benzene exposure and cancer risk were examined prospectively among male cohort members. The findings showed a small excess of overall cancer risk compared with the Norwegian general population, with increases of 7% among males and 13% among females. Elevated risks were observed for pleural mesothelioma, breast cancer, and prostate cancer in males, and for melanoma and acute myeloid leukaemia in females. Harmonization of overlapping employment records reduced the cohort's total employment duration by 10%, demonstrating the importance of this procedure for accurate exposure assessment. For lung cancer, a pattern of increased risk was observed with increasing benzene exposure, although these associations were not statistically significant for lung cancer overall. Positive associations were identified between duration of benzene exposure and lung adenocarcinoma. For CRC, positive associations were found for overall CRC, right sided colon cancer, and rectal cancer with respect to both average exposure intensity and duration. No clear associations were found for left sided colon cancer, although an increased risk was observed in the highest quartile of average intensity compared with unexposed workers. Overall, the thesis provides a detailed profile of the NOPW cohort, presents a method for handling overlapping employment records, and contributes with new insights into benzene’s etiological role for lung cancer and CRC.

• Marjerrison, Niki; Kjærheim, Jenny Kristina; Stenehjem, Jo; Grimsrud, Tom Kristian; Veierød, Marit Bragelien & Martinsen, Jan Ivar [Show all 9 contributors for this article] (2025). Kreftrisiko blant brannkonstabler 2015–2024. Folkehelseinstituttet. Full text in Research Archive Show summary

  Rapporten undersøker kreftrisiko blant norske brannkonstabler basert på en stor kohortstudie med nær 4700 ansatte fra 15 brannvesen. Studien viser at brannkonstabler har høyere forekomst av enkelte kreftformer enn den generelle befolkningen, særlig urinveiskreft, mesoteliom (brysthinnekreft), strupekreft, prostatakreft og tarmkreft. Risikoen var størst blant personer med lang ansettelsestid og blant dem som arbeidet i de tidligste periodene. Funnene gir særlig støtte til en sammenheng mellom yrkeseksponering ved brannslokking og risiko for urinveiskreft og mesoteliom. For prostatakreft kan den økte forekomsten delvis forklares av tidligere og hyppigere diagnostisering. Rapporten konkluderer med at resultatene støtter IARCs vurdering av brannyrket som kreftfremkallende, og understreker behovet for fortsatt forebygging og videre forskning på helsekonsekvenser av brannyrket

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