Magne Thoresen

• Djordjilovic, Vera; Page, Christian Magnus; Gran, Jon Michael; Nøst, Therese Haugdahl; Sandanger, Torkjel M; Veierød, Marit Bragelien & Thoresen, Magne (2019). Global test for high-dimensional mediation: Testing groups of potential mediators. Statistics in Medicine.  ISSN 0277-6715. . doi: 10.1002/sim.8199
• Fanaee-T, Hadi & Thoresen, Magne (2019). Performance evaluation of methods for integrative dimension reduction. Information Sciences.  ISSN 0020-0255.  493, s 105- 119 . doi: 10.1016/j.ins.2019.04.041
• Hansson, Patrik; Holven, Kirsten Bjørklund; Øyri, Linn Kristin Lie; Brekke, Hilde Kristin; Biong, Anne Sofie; Gjevestad, Gyrd Omholt; Raza, Ghulam S; Herzig, Kar-Heinz; Thoresen, Magne & Ulven, Stine Marie (2019). Meals with Similar Fat Content from Different Dairy Products Induce Different Postprandial Triglyceride Responses in Healthy Adults: A Randomized Controlled Cross-Over Trial. Journal of Nutrition.  ISSN 0022-3166.  149(3), s 422- 431 . doi: 10.1093/jn/nxy291
• Kollerud, Ruby Del Risco; Ruud, Ellen; Haugnes, Hege Sagstuen; Cannon-Albright, Lisa A.; Thoresen, Magne; Nafstad, Per; Vlatkovic, Ljiljana; Blaasaas, Karl Gerhard; Næss, Øyvind & Claussen, Bjørgulf (2019). Family history of cancer and risk of paediatric and young adult’s testicular cancer: A Norwegian cohort study. British Journal of Cancer.  ISSN 0007-0920.  120, s 1007- 1014 . doi: 10.1038/s41416-019-0445-2
• Romeo, Giovanni & Thoresen, Magne (2019). Model selection in high-dimensional noisy data: a simulation study. Journal of Statistical Computation and Simulation.  ISSN 0094-9655.  89(11), s 2031- 2050 . doi: 10.1080/00949655.2019.1607345
• Rundblad, Amanda; Larsen, Sunniva; Myhrstad, Mari; Ottestad, Inger; Thoresen, Magne; Holven, Kirsten Bjørklund & Ulven, Stine Marie (2019). Differences in peripheral blood mononuclear cell gene expression and triglyceride composition in lipoprotein subclasses in plasma triglyceride responders and non-responders to omega-3 supplementation. Genes & Nutrition.  ISSN 1555-8932.  14(10), s 1- 13 . doi: 10.1186/s12263-019-0633-y
• Thoresen, Magne (2019). Spurious interaction as a result of categorization 01 Mathematical Sciences 0104 Statistics. BMC Medical Research Methodology.  ISSN 1471-2288.  19(1), s 1- 8 . doi: 10.1186/s12874-019-0667-2
• Tork, Hadi Fanaee & Thoresen, Magne (2019). Multi-insight visualization of multi-omics data via ensemble dimension reduction and tensor factorization. Bioinformatics.  ISSN 1367-4803.  35(10), s 1625- 1633 . doi: 10.1093/bioinformatics/bty847
• Buonaccorsi, John P.; Romeo, Giovanni & Thoresen, Magne (2018). Model-based bootstrapping when correcting for measurement error with application to logistic regression. Biometrics.  ISSN 0006-341X.  74(1), s 135- 144 . doi: 10.1111/biom.12730
• Sørensen, Øystein; Hellton, Kristoffer Herland; Frigessi Di Rattalma, Arnoldo & Thoresen, Magne (2018). Covariate Selection in High-Dimensional Generalized Linear Models With Measurement Error. Journal of Computational And Graphical Statistics.  ISSN 1061-8600.  27(4), s 739- 749 . doi: 10.1080/10618600.2018.1425626 Show summary

  In many problems involving generalized linear models, the covariates are subject to measurement error. When the number of covariates p exceeds the sample size n, regularized methods like the lasso or Dantzig selector are required. Several recent papers have studied methods which correct for measurement error in the lasso or Dantzig selector for linear models in the p > n setting. We study a correction for generalized linear models, based on Rosenbaum and Tsybakov’s matrix uncertainty selector. By not requiring an estimate of the measurement error covariance matrix, this generalized matrix uncertainty selector has a great practical advantage in problems involving high-dimensional data. We further derive an alternative method based on the lasso, and develop efficient algorithms for both methods. In our simulation studies of logistic and Poisson regression with measurement error, the proposed methods outperform the standard lasso and Dantzig selector with respect to covariate selection, by reducing the number of false positives considerably. We also consider classification of patients on the basis of gene expression data with noisy measurements. Supplementary materials for this article are available online.

• Thoresen, Magne (2018). Er effekten forskjellig blant kvinner og menn?. Tidsskrift for Den norske legeforening.  ISSN 0029-2001.  138, s 1547 . doi: 10.4045/tidsskr.18.0602
• Thoresen, Magne (2018). Konfundering – et tilbakevendende problem. Tidsskrift for Den norske legeforening.  ISSN 0029-2001.  138, s 257 . doi: 10.4045/tidsskr.17.0795
• Ghosh, Abhik & Thoresen, Magne (2017). Non-concave penalization in linear mixed-effect models and regularized selection of fixed effects. AStA Advances in Statistical Analysis.  ISSN 1863-8171.  s 1- 32 . doi: 10.1007/s10182-017-0298-z Full text in Research Archive.
• Hellton, Kristoffer Herland & Thoresen, Magne (2017). When and Why are Principal Component Scores a Good Tool for Visualizing High-dimensional Data?. Scandinavian Journal of Statistics.  ISSN 0303-6898.  44, s 581- 597 . doi: 10.1111/sjos.12264 Full text in Research Archive.
• Thoresen, Magne (2017). Logistisk regresjon - anvendt og anvendelig. Tidsskrift for Den norske legeforening.  ISSN 0029-2001.  137(19) . doi: 10.4045/tidsskr.17.0309
• Buonaccorsi, John P.; Prochenka, Agnieszka; Thoresen, Magne & Ploski, Rafal (2016). Correcting for binomial measurement error in predictors in regression with application to analysis of DNA methylation rates by bisulfite sequencing. Statistics in Medicine.  ISSN 0277-6715.  35(22), s 3987- 4007 . doi: 10.1002/sim.6988
• Hellton, Kristoffer Herland & Thoresen, Magne (2016). Integrative clustering of high-dimensional data with joint and individual clusters. Biostatistics.  ISSN 1465-4644.  17(3), s 537- 548 . doi: 10.1093/biostatistics/kxw005 Full text in Research Archive.
• Leder, Lena; Kolehmainen, Marjukka; Narverud, Ingunn; Dahlman, Ingrid; Myhrstad, Mari; De Mello, Vanessa D.; Paananen, Jussi; Carlberg, Carsten; Schwab, Ursula; Herzig, Karl-Heinz; Cloetens, Lieselotte; Storm, Matilda Ulmius; Hukkanen, Janne; Savolainen, Markku J.; Rosqvist, Fredrik; Hermansen, Kjeld; Dragsted, Lars O.; Gunnarsdóttir, Ingibjörg; Thórsdóttir, Inga; Risérus, Ulf; Åkesson, Björn; Thoresen, Magne; Arner, Peter; Poutanen, Kaisa S.; Uusitupa, Matti; Holven, Kirsten Bjørklund & Ulven, Stine Marie (2016). Effects of a healthy Nordic diet on gene expression changes in peripheral blood mononuclear cells in response to an oral glucose tolerance test in subjects with metabolic syndrome: A SYSDIET sub-study. Genes & Nutrition.  ISSN 1555-8932.  11 . doi: 10.1186/s12263-016-0521-4
• Buonaccorsi, John P.; Dalen, Ingvild; Laake, Petter; Hjartåker, Anette; Engeset, Dagrun & Thoresen, Magne (2015). Sensitivity of regression calibration to non-perfect validation data with application to the Norwegian Women and Cancer Study. Statistics in Medicine.  ISSN 0277-6715.  34(8), s 1389- 1403 . doi: 10.1002/sim.6420
• Sørensen, Øystein; Frigessi, Arnoldo & Thoresen, Magne (2015). Measurement error in Lasso: Impact and likelihood bias correction. Statistica sinica.  ISSN 1017-0405.  25(2), s 809- 829 . doi: 10.5705/ss.2013.180 Full text in Research Archive.
• Tjelle, Torunn Elisabeth; Holtung, Linda; Bøhn, Siv Kjølsrud; Aaby, Kjersti; Thoresen, Magne; Wiik, Siv Åshild; Paur, Ingvild; Karlsen, Anette Solli; Retterstøl, Kjetil; Iversen, Per Ole & Blomhoff, Rune (2015). Polyphenol-rich juices reduce blood pressure measures in a randomised controlled trial in high normal and hypertensive volunteers. British Journal of Nutrition.  ISSN 0007-1145.  114(7), s 1054- 1063 . doi: 10.1017/S0007114515000562 Full text in Research Archive. Show summary

  Intake of fruits and berries may lower blood pressure (BP), most probably due to the high content of polyphenols. In the present study, we tested whether consumption of two polyphenol-rich juices could lower BP. In a randomised, double-blinded, placebo-controlled trial of 12 weeks, 134 healthy individuals, aged 50–70 years, with high normal range BP (130/85–139/89 mmHg, seventy-two subjects) or stage 1-2 hypertension (140/90–179/109 mmHg, sixty-two subjects), were included. They consumed 500 ml/d of one of either (1) a commercially available polyphenol-rich juice based on red grapes, cherries, chokeberries and bilberries; (2) a juice similar to (1) but enriched With polyphenol-rich extracts from blackcurrant press-residue or (3) a placebo juice (polyphenol contents 245·5, 305·2 and 76 mg/100 g, respectively). Resting BP was measured three times, with a 1 min interval, at baseline and after 6 and 12 weeks of intervention. Systolic BP significantly reduced over time (6 and 12 weeks, respectively) in the pooled juice group compared with the placebo group in the first of the three measurements, both for the whole study group (6·9 and 3·4 mmHg; P¼0·01) and even more pronounced in the hypertensive subjects when analysed separately (7·3 and 6·8 mmHg; P¼0·04). The variation in the BP measurements was significantly reduced in the pooled juice group compared with the placebo group (1·4 and 1·7 mmHg; P¼0·03). In conclusion, the present findings suggest that polyphenol-rich berry juice may contribute to a BP- and BP variability lowering effect, being more pronounced in hypertensive than in normotensive subjects.

• Hellton, Kristoffer Herland & Thoresen, Magne (2014). The Impact of Measurement Error on Principal Component Analysis. Scandinavian Journal of Statistics.  ISSN 0303-6898.  41(4), s 1051- 1063 . doi: 10.1111/sjos.12083 Full text in Research Archive.
• Mdala, Ibrahimu; Olsen, Ingar; Haffajee, Anne D; Socransky, Sigmund S; Thoresen, Magne & De Blasio, Birgitte Freiesleben (2014). Comparing clinical attachment level and pocket depth for predicting periodontal disease progression in healthy sites of patients with chronic periodontitis using multi-state Markov models. Journal of Clinical Periodontology.  ISSN 0303-6979.  41(9), s 837- 845 . doi: 10.1111/jcpe.12278
• Myhrstad, Mari; Ulven, Stine Marie; Günther, Clara-Cecilie; Ottestad, Inger; Holden, Marit; Ryeng, Einar; Borge, Grethe Iren Andersen; Kohler, Achim; Brønner, Kirsti Wettre; Thoresen, Magne & Holven, Kirsten Bjørklund (2014). Fish oil supplementation induces Expression of genes related to cell cycle, endoplasmic reticulum stress and apoptosis in peripheral blood mononuclear cells: a transcriptomic approach. Journal of Internal Medicine.  ISSN 0954-6820.  276(5), s 498- 511 . doi: 10.1111/joim.12217 Full text in Research Archive. Show summary

  Background Fish oil supplementation has been shown to alter gene expression of mononuclear cells both in vitro and in vivo. However, little is known about the total transcriptome profile in healthy subjects after intake of fish oil. We therefore investigated the gene expression profile in peripheral blood mononuclear cells (PBMCs) after intake of fish oil for 7 weeks using transcriptome analyses. Design In a 7-week, double-blinded, randomized, controlled, parallel-group study, healthy subjects received 8 g day−1 fish oil (1.6 g day−1 eicosapentaenoic acid + docosahexaenoic acid) (n = 17) or 8 g day−1 high oleic sunflower oil (n = 19). Microarray analyses of RNA isolated from PBMCs were performed at baseline and after 7 weeks of intervention. Results Cell cycle, DNA packaging and chromosome organization are biological processes found to be upregulated after intake of fish oil compared to high oleic sunflower oil using a moderated t-test. In addition, gene set enrichment analysis identified several enriched gene sets after intake of fish oil. The genes contributing to the significantly different gene sets in the subjects given fish oil compared with the control group are involved in cell cycle, endoplasmic reticulum (ER) stress and apoptosis. Gene transcripts with common motifs for 35 known transcription factors including E2F, TP53 and ATF4 were upregulated after intake of fish oil. Conclusion We have shown that intake of fish oil for 7 weeks modulates gene expression in PBMCs of healthy subjects. The increased expression of genes related to cell cycle, ER stress and apoptosis suggests that intake of fish oil may modulate basic cellular processes involved in normal cellular function.

• Mdala, Ibrahimu; Olsen, Ingar; Haffajee, Anne D; Socransky, Sigmund S; De Blasio, Birgitte Freiesleben & Thoresen, Magne (2013). Multilevel analysis of bacterial counts from chronic periodontitis after root planing/scaling, surgery, and systemic and local antibiotics: 2-year results. Journal of Oral Microbiology.  ISSN 2000-2297.  5 . doi: 10.3402/jom.v5i0.20939 Full text in Research Archive.
• Mdala, Ibrahimu; Olsen, Ingar; Haffajee, Anne D; Socransky, Sigmund S; Thoresen, Magne & De Blasio, Birgitte Freiesleben (2013). Kan vi forutsi områder i periodontiet som vil utvikle periodontitt?. Den norske tannlegeforenings tidende.  ISSN 0029-2303.  123(8), s 556- 557
• Skeie, Ivar; Brekke, Mette; Clausen, Thomas; Gossop, Michael; Lindbæk, Morten; Reinertsen, Even; Thoresen, Magne & Waal, Helge (2013). Increased Somatic Morbidity in the First Year after Leaving Opioid Maintenance Treatment: Results from a Norwegian Cohort Study. European Addiction Research.  ISSN 1022-6877.  19(4), s 194- 201 . doi: 10.1159/000345229
• Bøhn, Siv Kjølsrud; Russnes, Kjell Magne; Sakhi, Amrit Kaur; Thoresen, Magne; Holden, Marit; Moskaug, Jan Øivind; Myhrstad, Mari Charlotte; Olstad, Ole Kristoffer; Smeland, Sigbjørn & Blomhoff, Rune (2012). Stress associated gene expression in blood cells is related to outcome in radiotherapy treated head and neck cancer patients. BMC Cancer.  ISSN 1471-2407.  12 . doi: 10.1186/1471-2407-12-426 Show summary

  Background We previously observed that a radiotherapy-induced biochemical response in plasma was associated with favourable outcome in head and neck squamous carcinoma cancer (HNSCC) patients. The aim of the present study was to compare stress associated blood cell gene expression between two sub-groups of HNSCC patients with different biochemical responses to radiotherapy. Methods Out of 87 patients (histologically verified), 10 biochemical ‘responders’ having a high relative increase in plasma oxidative damage and a concomitant decrease in plasma antioxidants during radiotherapy and 10 ‘poor-responders’ were selected for gene-expression analysis and compared using gene set enrichment analysis. Results There was a significant induction of stress-relevant gene-sets in the responders following radiotherapy compared to the poor-responders. The relevance of the involvement of similar stress associated gene expression for HNSCC cancer and radioresistance was verified using two publicly available data sets of 42 HNSCC cases and 14 controls (GEO GSE6791), and radiation resistant and radiation sensitive HNSCC xenografts (E-GEOD-9716). Conclusions Radiotherapy induces a systemic stress response, as revealed by induction of stress relevant gene expression in blood cells, which is associated to favourable outcome in a cohort of 87 HNSCC patients. Whether these changes in gene expression reflects a systemic effect or are biomarkers of the tumour micro-environmental status needs further study.

• Halvorsen, Jon Anders; Dalgard, Florence; Thoresen, Magne; Bjertness, Espen & Lien, Lars (2012). Itch and Pain in Adolescents are Associated with Suicidal Ideation: A Population-based Cross-sectional Study. Acta Dermato-Venereologica.  ISSN 0001-5555.  92(5), s 543- 546 . doi: 10.2340/00015555-1251
• Mdala, Ibrahimu; Haffajee, Anne D; Socransky, Sigmund S; De Blasio, Birgitte Freiesleben; Thoresen, Magne; Olsen, Ingar & Goodson, Max J (2012). Multilevel analysis of clinical parameters in chronic periodontitis after root planing/scaling, surgery, and systemic and local antibiotics: 2-year results. Journal of Oral Microbiology.  ISSN 2000-2297.  4 . doi: 10.3402/jom.v4i0.17535
• Halvorsen, Jon Anders; Stern, Robert; Dalgard, Florence; Thoresen, Magne; Bjertness, Espen & Lien, Lars (2011). Suicidal Ideation, Mental Health Problems, and Social Impairment Are Increased in Adolescents with Acne: A Population-Based Study. Journal of Investigative Dermatology.  ISSN 0022-202X.  131(2), s 363- 370 . doi: 10.1038/jid.2010.264
• Lien, Lars; Green, Kristian; Thoresen, Magne & Bjertness, Espen (2011). Pain complaints as risk factor for mental distress: a three-year follow-up study. European Child and Adolescent Psychiatry.  ISSN 1018-8827.  20(10), s 509- 516 . doi: 10.1007/s00787-011-0211-3
• Skeie, Ivar; Brekke, Mette; Gossop, Michael; Lindbæk, Morten; Reinertsen, Even; Thoresen, Magne & Waal, Helge (2011). Changes in somatic disease incidents during opioid maintenance treatment: results from a Norwegian cohort study. BMJ Open.  ISSN 2044-6055.  1 . doi: 10.1136/bmjopen-2011-000130
• Bøhn, Siv Kjølsrud; Myhrstad, Mari Charlotte; Thoresen, Magne; Holden, Marit; Karlsen, Anette; Tunheim, Siv Haugen; Erlund, Iris; Svendsen, Mette; Seljeflot, Ingebjørg; Moskaug, Jan Øivind; Duttaroy, Asim K.; Laake, Petter; Arnesen, Harald; Tonstad, Serena; Collins, Andrew Richard; Drevon, Christian A & Blomhoff, Rune (2010). Blood cell gene expression associated with cellular stress defense is modulated by antioxidant-rich food in a randomised controlled clinical trial of male smokers. BMC Medicine.  ISSN 1741-7015.  8 . doi: 10.1186/1741-7015-8-54
• Halvorsen, Jon Anders; Stern, Robert; Dalgard, Florence; Thoresen, Magne; Bjertness, Espen & Lien, Lars (2010). Suicidal Ideation, Mental Health Problems, and Social Impairment Are Increased in Adolescents with Acne: A Population-Based Study. Journal of Investigative Dermatology.  ISSN 0022-202X.  131, s 363- 370 . doi: 10.1038/jid.2010.264
• Hjartaker, A; Thoresen, Magne; Engeset, Dagrun & Lund, Eiliv (2010). Dairy consumption and calcium intake and risk of breast cancer in a prospective cohort: The Norwegian Women and Cancer study. Cancer Causes and Control.  ISSN 0957-5243.  21(11), s 1875- 1885 . doi: 10.1007/s10552-010-9615-5 Full text in Research Archive.
• Lien, Lars; Green, Kristian; Thoresen, Magne & Bjertness, Espen (2010). Atopic conditions and mental health problems: a 3-year follow-up study. European Child and Adolescent Psychiatry.  ISSN 1018-8827.  19(9), s 705- 713 . doi: 10.1007/s00787-010-0106-8
• Sakhi, Amrit Kaur; Bøhn, Siv Kjølsrud; Smeland, Sigbjørn; Thoresen, Magne; Berge, Guro; Tausjø, Johan Elling; Svilaas, Arne B; Karlsen, Anette; Russnes, Kjell Magne; Svilaas, Tone & Blomhoff, Rune (2010). Postradiotherapy Plasma Lutein, alpha-Carotene, and beta-Carotene Are Positively Associated With Survival in Patients With Head and Neck Squamous Cell Carcinoma. Nutrition and Cancer.  ISSN 0163-5581.  62(3), s 322- 328 . doi: 10.1080/01635580903441188
• Clausen, Thomas; Waal, Helge; Thoresen, Magne & Gossop, Michael (2009). Mortality among opiate users: opioid maintenance therapy, age, and causes of death. Addiction.  ISSN 0965-2140.  104(8), s 1356- 1362 . doi: 10.1111/j.1360-0443.2009.02570.x
• Dalen, Ingvild; Buonaccorsi, JP; Sexton, Joseph; Laake, Petter & Thoresen, Magne (2009). Correction for misclassification of a categorized exposure in binary regression using replication data. Statistics in Medicine.  ISSN 0277-6715.  28(27), s 3386- 3410 . doi: 10.1002/sim.3712
• Green, Kristian; Tønnessen, Finn Egil; Tambs, K; Thoresen, Magne & Bjertness, Espen (2009). Dyslexia: group screening among 15-16-Year-Olds in Oslo, Norway. Scandinavian Journal of Educational Research.  ISSN 0031-3831.  53(3), s 217- 227 . doi: 10.1080/00313830902917246
• Halvorsen, Jon Anders; Dalgard, Florence; Thoresen, Magne; Bjertness, Espen & Lien, Lars (2009). Is the association between acne and mental distress influenced by diet? Results from a cross-sectional population study among 3775 late adolescents in Oslo, Norway. BMC Public Health.  ISSN 1471-2458.  9 . doi: 10.1186/1471-2458-9-340
• Halvorsen, Jon Anders; Dalgard, Florence; Thoresen, Magne; Bjertness, Espen & Lien, Lars (2009). Itch and Mental Distress: A Cross-Sectional Study among Late Adolescents. Acta Dermato-Venereologica.  ISSN 0001-5555.  89(1), s 39- 44 . doi: 10.2340/00015555-0554
• Sakhi, Amrit Kaur; Russnes, Kjell Magne; Thoresen, Magne; Bastani, Nasser Ezzatkhah; Karlsen, Anette; Smeland, Sigbjørn & Blomhoff, Rune (2009). Pre-radiotherapy plasma carotenoids and markers of oxidative stress are associated with survival in head and neck squamous cell carcinoma patients: a prospective study. BMC Cancer.  ISSN 1471-2407.  9(1), s 458
• BØ, KRISTINE; Thoresen, Magne & Dalgard, Florence (2008). Smokers report more psoriasis, but not atopic dermatitis or hand eczema: Results from a Norwegian population survey among adults. Dermatology.  ISSN 1018-8665.  216 . doi: 10.1159/000109357
• Halvorsen, Jon Anders; Olesen, Anne Braae; Thoresen, Magne; Holm, Jan-Øivind; Bjertness, Espen & Dalgard, Florence (2008). Comparison of Self-reported Skin Complaints with Objective Skin Signs among Adolescents. Acta Dermato-Venereologica.  ISSN 0001-5555.  88, s 573- 577 . doi: 10.2340/00015555-0505
• Karlsen, Anette; Svendsen, Mette; Brevik, Asgeir; Bøhn, Siv K; Myhrstad, Mari C.W.; Thoresen, Magne; Seljeflot, Ingebjørg; Arnesen, Harald; Erlund, Iris; Serafini, Mauro; Remberg, Siv Fagertun; Haffner, Karin; Borge, Grethe Iren Andersen; Dragsted, Lars; Laake, Petter; Drevon, Christian A.; Collins, Andrew; Tonstad, Serena & Blomhoff, Rune (2008). Dietary intake of antioxidant-rich foods increase plasma antioxidants, enhance DNA repair capacity and reduce blood pressure in smoking, middle-aged men, In  PhD Thesis.  Universitetet i Oslo, Institutt for ernæringsforskning.  faglig_bok_institusjon.
• Sagatun, Åse; Kolle, Elin; Anderssen, Sigmund A.; Thoresen, Magne & Søgaard, Anne-Johanne (2008). Three-year follow-up of physical activity in Norwegian youth from two ethnic groups: associations with socio-demographic factors. BMC Public Health.  ISSN 1471-2458.  8 . doi: 10.1186/1471-2458-8-419 Show summary

  Background: More research on factors associated with physical activity and the decline in participation during adolescence is needed. In this paper, we investigate the levels, change, and stability of physical activity during the late teens among ethnic Norwegians and ethnic minorities, and we examine the associations between physical activity and socio-demographic factors. Methods: The baseline (T1) of this longitudinal study included 10th graders who participated in the youth part of the Oslo Health Study, which was carried out in schools in 2000–2001. The follow-up (T2) in 2003–2004 was conducted partly at school and partly by mail. A total of 2489 (1112 boys and 1377 girls) participated both at baseline and at follow-up. Physical activity level was measured by a question on weekly hours of physical activity outside of school. Socio-demographic variables were collected by questionnaire and from data obtained from Statistics Norway. Analysis of variance was used to study the level of and changes (T1 to T2) in physical activity, and the associations between physical activity and socio-demographic factors. Stability in physical activity was defined as the percentage of students reporting the same physical activity both times. Results: Boys were more active than girls at age 15 and 18 years, independent of ethnic background. Among girls, ethnic Norwegians were more active than ethnic minorities. Hours per week spent on physical activity declined in all groups during the follow-up period. Few associations were found between physical activity and socio-demographic factors in both cross-sectional and longitudinal data. Among the ethnic minority girls, 65% reported being physically active 0–2 hours per week at baseline, and 82% of these girls reported the same level at follow up. Conclusion: The association between physical activity and ethnicity at age 15 years remained the same during the follow-up. Few associations were found between physical activity and socio-demographic variables. A large proportion of ethnic minority girls reported a persistently low physical activity level, and this low participation rate may need special attention.

• Abudayya, Abdallah; Thoresen, Magne; Abed, Y & Holmboe-Ottesen, Gerd (2007). Overweight, stunting, and anemia are public health problems among low socioeconomic groups in school adolescents (12-15 years) in the North Gaza Strip. Nutrition Research.  ISSN 0271-5317.  27, s 762- 771 . doi: 10.1016/j.nutres.2007.09.017
• Laake, Petter; Thoresen, Magne & Veierød, Marit Bragelien (2007). Målefeilsproblemer, I: Petter Laake; Anette Hjartåker; Dag Steinar Thelle & Marit Bragelien Veierød (red.),  Epidemiologiske og kliniske forskningsmetoder.  Gyldendal Akademisk.  ISBN 978-82-05-33505-9.  4.  s 128 - 168
• Lien, Lars; Haavet, Ole Rikard; Thoresen, Magne; Heyerdahl, Sonja & Bjertness, Espen (2007). Mental health problems, negative life events, perceived pressure and the frequency of acute infections among adolescents - Results from a cross-sectional, multicultural, population-based study. Acta Paediatrica.  ISSN 0803-5253.  96, s 301- 306 . doi: 10.1111/j.1651-2227.2007.00084.x Show summary

  Aim: To study the association between mental health problems, negative life events, perceived pressure at school and the frequency of acute infectious illnesses in an adolescent population, and to explore whether the association differs by sex and immigration status. Methods: A cross-sectional study involving all tenth grade pupils in Oslo in 2000 and 2001. Of 8316 eligible pupils, 7346 participated in the study, giving a participation rate of 88%. Twenty-four percent of participants were first- or second-generation immigrants. Results: Mental health problems and negative life events were associated with the number of acute infections in a population-based setting, even after adjustment for possible confounding factors. For girls with an immigrant background, internalised mental health problems and own serious illness or injury had the strongest association with acute infections. For adolescents with a non-immigrant background, experiencing sexual violence had the strongest association, and for native-born boys the strongest association with acute infections was externalised mental health problems. Smoking was the cofactor with the strongest association to acute infections. Conclusion: There is a relationship between acute infection, mental health problems and negative life events among adolescents in a multicultural population-based setting.

• Thoresen, Magne (2007). A note on correlated errors in exposure and outcome in logistic regression. American Journal of Epidemiology.  ISSN 0002-9262.  166, s 465- 471 . doi: 10.1093/aje/kwm107
• Thoresen, Magne & Laake, Petter (2007). A simulation study of statistical tests in logistic measurement error models. Journal of Statistical Computation and Simulation.  ISSN 0094-9655.  77, s 683- 694 . doi: 10.1080/10629360600589541
• Thoresen, Magne & Laake, Petter (2007). On the simple linear regression model with correlated measurement errors. Journal of Statistical Planning and Inference.  ISSN 0378-3758.  137, s 68- 78
• Strand, Elin Bolle; Zautra, Alex J; Thoresen, Magne; Ødegård, Sigrid; Uhlig, Till & Finset, Arnstein (2006). Positive affect as a factor of resilience in the pain-negative affect relationship in patients with rheumatoid arthritis. Journal of Psychosomatic Research.  ISSN 0022-3999.  60(5), s 477- 484
• Bøhn, Siv Kjølsrud; Smeland, Sigbjørn; Sakhi, Amrit Kaur; Thoresen, Magne; Russnes, Kjell Magne; Tausjø, Johan; Svilaas, Arne; Svilaas, Tone & Blomhoff, Rune (2006). Post-radiotherapy plasma total glutathione is associated to outcome in patients with head and neck squamous cell carcinoma. Cancer Letters.  ISSN 0304-3835.  238(2), s 240- 247
• Dalen, Ingvild; Buonaccorsi, John P.; Laake, Petter; Hjartåker, Anette & Thoresen, Magne (2006). Regression analysis with categorized regression calibrated exposure: some interesting findings. Emerging Themes in Epidemiology.  ISSN 1742-7622.  3(6) . doi: 10.1186/1742-7622-3-6
• Lien, Lars; Dalgard, Florence; Heyerdahl, Sonja; Thoresen, Magne & Bjertness, Espen (2006). The relationship between age of menarche and mental distress in Norwegian adolescent girls and girls from different immigrant groups in Norway: Results from an urban city cross-sectional survey. Social Science and Medicine.  ISSN 0277-9536.  63(2), s 285- 295 . doi: /10.1016/j.socscimed.2006.01.003
• Lien, Lars; Lien, Nanna; Heyerdahl, Sonja; Thoresen, Magne & Bjertness, Espen (2006). Consumption of soft drinks and hyperactivity, mental distress, and conduct problems among adolescents in Oslo, Norway. American Journal of Public Health.  ISSN 0090-0036.  96(5), s 1815- 1820 . doi: 10.2105/AJPH.2004.059477 Show summary

  Objectives. We examined whether high levels of consumption of sugar-containing soft drinks were associated with mental distress, hyperactivity, and conduct problems among adolescents. Methods. A cross-sectional population-based survey was conducted with 10th-grade students in Oslo, Norway (n = 5498). We used the Hopkins Symptom Checklist and the Strengths and Difficulties Questionnaire to assess mental health outcomes. Results. There was a J-shaped dose–response relationship between soft drink consumption and mental distress, conduct problems, and total mental health difficulties score; that is, adolescents who did not consume soft drinks had higher scores (indicating worse symptoms) than those who consumed soft drinks at moderate levels but lower scores than those with high consumption levels. The relationship was linear for hyperactivity. In a logistic regression model, the association between soft drink consumption and mental health problems remained significant after adjustment for behavioral, social, and food-related variables. The highest adjusted odds ratios were observed for conduct problems among boys and girls who consumed 4 or more glasses of sugar-containing soft drinks per day. Conclusions. High consumption levels of sugar-containing soft drinks were associated with mental health problems among adolescents even after adjustment for possible confounders.

• Lien, Lars; Oppedal, Brit; Haavet, Ole Rikard; Hauff, Edvard; Thoresen, Magne & Bjertness, Espen (2006). Own and parental war experience as a risk factor for mental health problems among adolescents with an immigrant ackground: results from a cross sectional study in Oslo, Norway. Clinical Practice and Epidemiology in Mental Health.  ISSN 1745-0179.  2 . doi: 10.1186/1745-0179-2-30
• Thoresen, Magne (2006). Correction for measurement error in multiple logistic regression: A simulation study. Journal of Statistical Computation and Simulation.  ISSN 0094-9655.  76, s 475- 487
• Aarås, Arne; Horgen, Gunnar; Ro, Ola; Løken, Ellen; Mathiasen, Geir; Bjørset, Hans Henrik; Larsen, Stig & Thoresen, Magne (2005). The effect of an ergonomic intervention on musculoskeletal, psychosocial and visual strain of VDT data entry work: the Norwegian part of the international study. International Journal of Occupational Safety and Ergonomics.  ISSN 1080-3548.  11|(1), s 25- 47
• Dainoff, Marvin; Aarås, Arne; Horgen, Gunnar; Konarska, Maria; Larsen, Stig; Thoresen, Magne & Cohen, Barbara (2005). The effect of an ergonomic intervention on musculoskeletal, psychosocial and visual strain of VDT entry work: organization and methodology of the international study. International Journal of Occupational Safety and Ergonomics.  ISSN 1080-3548.  11(1), s 9- 23
• Horgen, Gunnar; Aarås, Arne; Dainoff, Marvin; Konarska, Maria; Thoresen, Magne & Cohen, Barbara (2005). A cross-country comparison of short- and long-term effects of an ergonomic intervention on musculoskeletal discomfort, eyestrain and psychosocial stress in VDT operators: Selected aspects of the international project. International Journal of Occupational Safety and Ergonomics.  ISSN 1080-3548.  11(1), s 77- 92
• Lien, Lars; Claussen, Bjørgulf; Hauff, Edvard; Thoresen, Magne & Bjertness, Espen (2005). Bodily pain and associated mental distress among immigrant adolescents. A population-based cross-sectional study. European Child and Adolescent Psychiatry.  ISSN 1018-8827.  14(7), s 371- 375
• Aarås, Arne; Horgen, Gunnar; Horgen, Gunnar; Løken, Ellen; Mathiasen, Geir; Bjørset, Hans-Henrik; Larsen, Stig & Thoresen, Magne (2005). The Effect of an Ergonomic Intervention on Musculoskeletal, Psychosocial and Visual Strain of VDT Data Entry Work: The Norwegian Part of the International Study. International Journal of Occupational Safety and Ergonomics.  ISSN 1080-3548.  11(no 1), s 25- 47 Show summary

  The Norwegian MEPS (musculoskeletal—eyestrain—psychosocial—stress) study included 3 groups: data entry, data dialogue (female) and data dialogue (male). Before intervention, the data entry group reported significantly more symptoms and signs of musculoskeletal illness and had longer periods in front of the video display terminal (VDT) without a break. The ergonomic intervention consisted mainly of ergonomic information and training. After intervention, the data dialogue female group reported a significant reduction in shoulder pain in parallel with a reduction in trapezius load. Increasing the understanding in how to adjust the work stand and chair may have been contributing factors to reducing the pain level. There was a significant reduction in eye problems in all groups; the greatest reduction in eye symptoms was seen in the groups who had new optometric corrections.

• Dainoff, Marvin J.; Aarås, Arne; Horgen, Gunnar; Horgen, Gunnar; Konarska, Maria; Larsen, Stig; Thoresen, Magne & Cohen, Barbara G.F. (2005). The Effect of an Ergonomic Intervention on Musculoskeletal, Psychosocial and Visual Strain of VDT Entry Work: Organization and Methodology of the International Study. International Journal of Occupational Safety and Ergonomics.  ISSN 1080-3548.  11(nr 1), s 9- 23 Show summary

  This special issue of the International Journal of Occupational Safety and Ergonomics (JOSE) reports the results from an extensive multinational and multidisciplinary collaborative investigation of the impacts on visual display terminal (VDT) work of musculoskeletal, visual, ergonomic, and psychosocial factors. For brevity, this effort has been referred to as the MEPS project (musculoskeletal—eyestrain—psychosocial—stress). This paper lays out the basic methodological structure of the study. The study was conducted in 4 countries utilizing VDT data entry workers as the primary subject population. A battery of objective and subject assessment measures, including muscle load, visual function, physical and visual strain, postural, ergonomic and psychosocial factors, were assessed at 3 different points in time. A pre-test was given prior to an ergonomic intervention. Two posttests were given 1 month and 1 year after the ergonomic intervention

• Horgen, Gunnar; Aarås, Arne; Dainoff, Marvin J.; Konarska, Maria; Thoresen, Magne & Cohen, Barbara G.F. (2005). A Cross-Country Comparison of Short and Long-Term Effects of an Ergonomic Intervention on Musculoskeletal Discomfort, Eyestrain and Psychosocial Stress in VDT Operators: Selected Aspects of the International Project. International Journal of Occupational Safety and Ergonomics.  ISSN 1080-3548.  11(no 1), s 77- 92 Show summary

  Three groups of data entry female visual display terminal (VDT) workers from Norway (n = 30), Poland (n = 33) and the USA (n = 29) were compared. Before intervention, the Norwegian group reported more neck pain compared with the Polish group. The Polish group reported less shoulder pain than both the U.S. and the Norwegian groups. The clinical examination documented fewer symptoms and signs of musculoskeletal illness among the Polish participants compared with the Norwegian and the U.S. groups. Afterintervention, the Norwegian group reported a reduction in neck pain while the U.S. group reported a reduction in shoulder pain. The Polish group reported an increase in neck, shoulder and forearm pain at follow-up compared to after intervention. The Polish group recorded higher flexion of the upper arm at follow-up parallel with an increase of pain in the upper part of the body. Visual discomfort showed variable results in the 3 countries.

• Melberg, Tor; Thoresen, Magne; Hansen, John-Bjarne & Westheim, Arne (2005). Hvordan behandles pasienter med akutt koronarsyndrom i norske sykehus?. Tidsskrift for Den norske legeforening.  ISSN 0029-2001.  125(21), s 2925- 2928
• Horgen, Gunnar; Aarås, Arne & Thoresen, Magne (2004). Will visual discomfort among visual display unit (VDU) users change in development when moving from single vision lenses to specially designed VDU progressive lenses?. Optometry and Vision Science.  ISSN 1040-5488.  81(5), s 341- 349 Show summary

  Abstract PURPOSE: Three types of optometric corrections specially designed for VDU-work ("VDU-progressives") and one single vision lens were compared in a prospective field study. The aim was to investigate if these progressive lenses created a difference in the development of visual discomfort compared to single vision lenses (SV) when working on an optimized VDU-workstation. METHODS: The study had a prospective, parallel group design, with four groups of VDU-workers. Approximately 40 subjects in each group, selected after careful task analysis with special attention towards the visual angles and distances to the work tasks. The groups were followed over one year. A questionnaire concerning visual conditions, working conditions, discomfort in different body areas, the status of the subjects' optometric corrections, psychological factors both at work and at home, amount, frequency and durationof VDU-work etc. was filled in before the intervention, after six months and after one year. No other contact was made with the subjects. The VDU-lenses included were Interview (I) (Essilor), Gradal RD (R) (Zeiss) and Technica (T) (American Optical). Pain intensity and duration were assessed on a 10 cm. Visual Analogue Scale before the intervention, and six and twelve months after the intervention. All subjects were givena complete optometric examination. RESULTS. Only small changes in the development of headache and visual discomfort wereregistered. However, the subjective evaluation of area of clear vision and overall satisfaction was significantly improved for the I and R lens (P<0,05). There were no significant changes for T and SV lenses. CONCLUSION: Lens designs that cover viewing distances from near and out to approximately 2 meters works well compared to lens designs trying to cover greater range of clear vision. When tasks analysis shows that single vision correction may be used, this is still an acceptable solution.

• Thoresen, Magne (2004). Will visual discomfort among visual display unit (VDU) users change in development when moving from single vision lenses to specially designed VDU progressive lenses?. Optometry and Vision Science.  ISSN 1040-5488.  81(5), s 341- 349
• Carlsen, Harald; Myhrstad, Mari Charlotte; Thoresen, Magne; Moskaug, Jan Øivind & Blomhoff, Rune (2003). Berry intake increases the activity of the gamma-glutamylcysteine synthetase promoter in transgenic reporter mice. Journal of Nutrition.  ISSN 0022-3166.  133(7), s 2137- 2140
• Thoresen, Magne (2003). Målefeil i regresjonsanalyse. Norsk Epidemiologi.  ISSN 0803-2491.  13(2), s 257- 263
• Thoresen, Magne & Laake, Petter (2003). The use of replicates in logistic measurement error modelling. Scandinavian Journal of Statistics.  ISSN 0303-6898.  30(3), s 625- 636

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• Thoresen, Magne (2019). Det problematiske oddsforholdet. Tidsskrift for Den norske legeforening.  ISSN 0029-2001.  139(7) . doi: 10.4045/tidsskr.19.0011
• Hansson, Patrik; Holven, Kirsten Bjørklund; Øyri, Linn Kristin Lie; Brekke, Hilde Kristin; Biong, Anne Sofie; Gjevestad, Gyrd Omholt; Thoresen, Magne & Ulven, Stine Marie (2018). Postprandial effects of different dairy products on triglycerides in lean and overweight subjects: a randomized controlled cross-over study.
• Hansson, Patrik; Holven, Kirsten Bjørklund; Øyri, Linn Kristin Lie; Brekke, Hilde Kristin; Biong, Anne Sofie; Gjevestad, Gyrd Omholt; Thoresen, Magne & Ulven, Stine Marie (2018). Postprandial effects of different dairy products on triglycerides in lean and overweight subjects: a randomized controlled cross-over study.
• Hansson, Patrik; Holven, Kirsten Bjørklund; Øyri, Linn Kristin Lie; Brekke, Hilde Kristin; Gjevestad, Gyrd Omholt; Thoresen, Magne & Ulven, Stine Marie (2018). SEX DIFFERENCES IN POSTPRANDAL RESPONSE TO DIFFERENT DAIRY PRODUCTS ON LIPOPROTEIN SUBCLASSES: A RANDOMIZED CONTROLLED CROSS-OVER TRIAL.
• Larsen, Sunniva Veen; Holven, Kirsten Bjørklund; Flatberg, Arnar; Christensen, Jacob J.; Leder, Lena; Blomhoff, Rune; Kolehmainen, Marjukka; Carlberg, Carsten; Myhrstad, Mari; Thoresen, Magne & Ulven, Stine Marie (2018). Effects of replacing saturated fatty acids with polyunsaturated fatty acids on gene expression profiles of human peripheral blood mononuclear cells: a double-blind randomised controlled trial.
• Rundblad, Amanda; Larsen, Sunniva Veen; Myhrstad, Mari; Ottestad, Inger; Thoresen, Magne; Holven, Kirsten Bjørklund & Ulven, Stine Marie (2018). Gene expression changes in plasma triglyceride responders and non-responders to omega-3 supplementation.
• Hansson, Patrik; Holven, Kirsten Bjørklund; Øyri, Linn Kristin Lie; Brekke, Hilde Kristin; Biong, Anne Sofie; Gjevestad, Gyrd Omholt; Thoresen, Magne & Ulven, Stine Marie (2017). Postprandial effects of different dairy products on blood lipids in lean and overweight subjects.
• Hellton, Kristoffer Herland & Thoresen, Magne (2015). On high-dimensional principal component analysis in genomics: consistency and robustness.
• Ørn, Stein & Thoresen, Magne (2015). Growth mixture modeling: the new statistical kid on the block?. Journal of Cardiac Failure.  ISSN 1071-9164.  21(6), s 446- 447
• Mdala, Ibrahimu; Haffajee, Anne D; Socransky, Sigmund S; De Blasio, Birgitte Freiesleben; Thoresen, Magne; Goodson, Max J & Olsen, Ingar (2012). Hvilken type periobehandling gir best kliniske resultater over tid?.
• Mdala, Ibrahimu; Haffajee, Anne D; Socransky, Sigmund S; De Blasio, Birgitte Freiesleben; Thoresen, Magne & Olsen, Ingar (2012). Hvilken behandling gir de gunstigste endringer i periodontal mikroflora over tid?.
• Mdala, Ibrahimu; Haffajee, Anne D; Socransky, Sigmund S; Thoresen, Magne; De Blasio, Birgitte Freiesleben & Olsen, Ingar (2012). Multistate Markov models for predicting changes in sulcus/pocket depth and attachment level of healthy and diseased sites in chronic periodontitis.
• Bøhn, Siv Kjølsrud; Blomhoff, Rune & Thoresen, Magne (2011). Antioxidant-rich foods induce genes associated with stress defence : implications for cancer and other oxidative stress related conditions.
• Mdala, Ibrahimu; Haffajee, AD; Socransky, SS; De Blasio, Birgitte Freiesleben; Thoresen, Magne & Olsen, Ingar (2010). Multilevel analysis of clinical parameters in chronic periodontitis after root planing/scaling, surgery and systemic and local antibiotics: 2-years results.
• Bøhn, Siv Kjølsrud; Myhrstad, Mari Charlotte; Thoresen, Magne; Marciuch, Anne; Vasstrand, Ann kristin; Carlsen, Monica Hauger; Bastani, Nasser Ezzatkhah; Olstad, Ole Kristoffer; Engedal, K; Sandvik, L.; Bjørklund, Roald Arild; Flekkøy, Kjell- Magne & Blomhoff, Rune (2009). Effect of berry and grape polyphenols on cognition and blood parameters in normal, aged men with subjective memory decline.
• Bøhn, Siv Kjølsrud; Myhrstad, Mari Charlotte; Thoresen, Magne; Holden, Marit; Tunheim, Siv Haugen; Karlsen, Anette; Svendsen, Mette; Seljeflot, Ingebjørg; Moskaug, Jan Øivind; Duttaroy, Asim K.; Laake, Petter; Drevon, Christian A; Arnesen, Harald; Tonstad, Serena; Collins, Andrew Richard & Blomhoff, Rune (2008). Plant food phytochemicals modulate gene expression in human blood cells.
• Flekkøy, Kjell- Magne; Engedal, Knut Arne; Bohn, Siv kjølsrud; Myhrstad, Mari; Thoresen, Magne; Carlsen, Monica h.; Marciuch, Anne; Vasstrand, Ann kristin; Sandvik, Leiv; Bjørklund, Roald Arild & Blomhoff, Rune (2008). Effect of berry polyphenols on cognition and clinical parameters in normal, aged men with subjective memory decline. A pilot study.
• Lien, Lars; Djurovic, Srdjan; Thoresen, Magne; Bjertness, Espen & Andreassen, Ole Andreas (2008). Interaction between health behaviour, mental distress and the polymorphism of the serotonin transporter gene among adolescents in Oslo, Norway. European psychiatry.  ISSN 0924-9338.  23, s S174- S174
• Strand, Elin Bolle; Zautra, Alex J & Thoresen, Magne (2006). Positive affect as a factor of resilience in the pain-negative affect relationship in patients with rheumatoid arthritis - a weekly assessment study.
• Strand, Elin Bolle; Zautra, Alex J; Thoresen, Magne & Finset, Arnstein (2006). Positive affect as a factor of resilience at pain fluctuations in patients with rheumatoid arthritis.
• Melberg, Tor; Thoresen, Magne; Hansen, John-Bjarne & Westheim, Arne (2005). Behandling av pasienter med akutt koronarsyndrom i norske sykehus: T. Melberg og medarbeidere svarer. Tidsskrift for Den norske legeforening.  ISSN 0029-2001.  125, s 3522- 3522
• Strand, Elin Bolle; Zautra, Alex J; Thoresen, Magne & Finset, Arnstein (2005). Positive affect as a buffer in the pain-negative affect relationship.
• Strand, Elin Bolle; Thoresen, Magne; Finset, Arnstein & Zautra, Alex J (2004). Does positive affect buffer the relationship between pain and negative affect?.
• Strand, Elin Bolle; Thoresen, Magne; Finset, Arnstein & Zautra, Alex J (2004). Positive affect as a buffer of the pain-negative affect relationship in Rheumatoid arthritis patients?.
• Strand, Elin Bolle; Thoresen, Magne; Finset, Arnstein & Zautra, Alex J (2004). Positive affect as a buffer of the pain-negative affect relationship in rheumatoid arthritis patients?.
• Strand, Elin Bolle; Thoresen, Magne & Finset, Arnstein (2003). Does positive affect buffer the relationship between pain and negative affect in patients with rheumatoid arthritis?.

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