Kristian Green Krogshus

• Tamnes, Christian K.; Bekkhus, Mona; Eilertsen, Maja; Nes, Ragnhild Bang; Prydz, Monica Beer & Ystrom, Eivind [Show all 63 contributors for this article] (2025). The nature of the relation between mental well-being and ill-being. Nature Human Behaviour. 9(12), p. 2431–2440. doi: 10.1038/s41562-025-02319-x. Full text in Research Archive
• 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), p. 509–516. doi: 10.1007/s00787-011-0211-3. 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), p. 705–713. doi: 10.1007/s00787-010-0106-8. Full text in Research Archive
• Bjertness, Espen; Sagatun, Åse; Green, Kristian; Lien, Lars; Søgaard, Anne-Johanne & Selmer, Randi Marie (2010). Response rates and selection problems, with emphasis on mental health variables and DNA sampling, in large population-based, cross-sectional and longitudinal studies of adolescents in Norway. BMC Public Health. 10. doi: 10.1186/1471-2458-10-602. Full text in Research Archive Show summary

  Background: Selection bias is a threat to the internal validity of epidemiological studies. In light of a growing number of studies which aim to provide DNA, as well as a considerable number of invitees who declined to participate, we discuss response rates, predictors of lost to follow-up and failure to provide DNA, and the presence of possible selection bias, based on five samples of adolescents. Methods: We included nearly 7,000 adolescents from two longitudinal studies of 18/19 year olds with two corresponding cross-sectional baseline studies at age 15/16 (10th graders), and one cross-sectional study of 13th graders (18/19 years old). DNA was sampled from the cheek mucosa of 18/19 year olds. Predictors of lost to follow-up and failure to provide DNA were studied by Poisson regression. Selection bias in the follow-up at age 18/19 was estimated through investigation of prevalence ratios (PRs) between selected exposures (physical activity, smoking) and outcome variables (general health, mental distress, externalizing problems) measured at baseline. Results: Out of 5,750 who participated at age 15/16, we lost 42% at follow-up at age 18/19. The percentage of participants who gave their consent to DNA provision was as high as the percentage that consented to a linkage of data with other health registers and surveys, approximately 90%. Significant predictors of lost to follow-up and failure to provide DNA samples in the present genetic epidemiological study were: male gender; non-western ethnicity; postal survey compared with school-based; low educational plans; low education and income of father; low perceived family economy; unmarried parents; poor self-reported health; externalized symptoms and smoking, with some differences in subgroups of ethnicity and gender. The association measures (PRs) were quite similar among participants and all invitees, with some minor discrepancies in subgroups of non-western boys and girls. Conclusions: Lost to follow-up had marginal impact on the estimated prevalence ratios. It is not likely that the invitation to provide DNA influenced the response rates of 18/19 year olds. Non-western ethnicity, male gender and characteristics related to a low social class and general and mental health problems measured at baseline are associated with lost to follow-up and failure to provide DNA.

• Lien, Lars; Green, Kristian; Welander-Vatn, Audun & Bjertness, Espen (2009). Mental and somatic health complaints associated with school bullying between 10th and 12th grade students; results from cross sectional studies in Oslo, Norway. Clinical Practice and Epidemiology in Mental Health. 23(5). doi: 10.1186/1745-0179-5-6. Full text in Research Archive Show summary

  Background Bullying is a widespread and serious problem that might influence both mental and psychical well being as well as school performance and social life. The aim of this study was to describe the prevalence of bullying, mental health problems and psychical complaints among 10th and 12th grade students and to analyze the association between bullying, mental health problems and muscle and skeletal complaints. Methods Two cross sectional studies of adolescents living in Oslo, Norway the first conducted in 2001 among 10th grade students (15/16 years old) and the second in 2004 among 12th grade students (18/19 years old). Both surveys were based on self report, were mostly school based and had almost identical questionnaires. There were around 3700 participants in both surveys, but the participation rate was lower in the latter survey (88 versus 80%). The Hopkins Symptoms Check List (HSCL-10) and the Strength and Difficulties Questionnaire (SDQ) were used to measure mental health problems. Results Bullying is decreasing both among boys and girls while the prevalence of internalized mental health problems are increasing from 10th to 12th grade. For muscle and skeletal pain there is a diverging trend between boys and girls, with an increase among girls and a decrease among boys. The highest Odds Ratios, as a measure for the association between bullying, mental health problems and pain, were found for internalized mental health problems at both 10th and 12th grade both for boys and girls. Conclusion Both internalized and externalized mental health problems together with pain seem to be associated with bullying irrespective of school type and gender.

• 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), p. 217–227. doi: 10.1080/00313830902917246. Full text in Research Archive
• Green, Kristian; Heyerdahl, Sonja; Dalgard, Odd Steffen & Bjertness, Espen (2003). Psykososiale problemer hos ungdom med lese-/skrivevansker. Norsk Epidemiologi. ISSN 0803-2491. 13, p. 35–35. Full text in Research Archive

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• Krogshus, Kristian Green; Bjertness, Espen; Czajkowski, Nikolai Olavi; Rodriguez-Cano, Ruben & Nes, Ragnhild Bang (2025). Study protocol for 5Ways@School – An implementation and effectiveness trial of a school-based wellbeing intervention in 16 schools in Norway. doi: 10.1177/14034948251370109. Full text in Research Archive Show summary

  Aims: This study aims to assess the effectiveness and implementation of the 5Ways@School curriculum-based intervention in Norwegian schools. The intervention builds on the Five Ways to Wellbeing framework, and promotes five action domains: connect with others, be physically active, take notice, keep learning, and give. The study objectives include assessing the intervention’s acceptability, appropriateness, feasibility, fidelity, and cost, as well as its impact on students’ wellbeing and mental health. Methods: The study is a hybrid effectiveness–implementation trial using mixed methods. It is a longitudinal, two-armed, non-randomized, controlled study involving students in grades 5 to 10 (ages 10 to 16). The primary outcomes are the intervention’s acceptability and feasibility, and its effectiveness on students’ wellbeing. Data collection includes web-based questionnaires for students and teachers, and qualitative interviews with teachers. Quantitative data will be analysed using multilevel regression models and network intervention analysis, while qualitative data will be analysed using thematic analysis. Conclusions: The study aims to provide insights into the implementation and effectiveness of the wellbeing-promoting 5Ways@School intervention. The findings could inform the optimization of the 5Ways@School and other future school-based interventions, and thereby contribute to the wellbeing of children and young people. The study’s strengths include its real-life school setting and mixed methods approach, while limitations include its non-randomized design. Trial registration: ClinicalTrials.gov, ID NCT06144502.

• Nes, Karoline; Green, Kristian; Kristensen, Petter & Bjertness, Espen (2003). Sjukdom og psykiske symptom i ungdomsåra og sosial mobilitet. Full text in Research Archive
• Green, Kristian; Oppedal, Brit; Wilmar, Bente; Stang, Grete Hovind & Bjertness, Espen (2002). Lese-/skrivevansker: Akademisk mestring og sosial støtte fra medelever og lærere. Full text in Research Archive Show summary

  Formål: Formålet med undersøkelsen er å studere faktorer assosiert med lese-/skrive-vansker, akademisk mestring (karakterer), og sosial støtte fra medelever og lærere. Materiale og metoder: Studien baserer seg på data fra Helseundersøkelsen i bydeler og regioner i Oslo (HUBRO). Alle 10.-klassinger i 1999/00 og 2000/01 ble invitert til å delta (N=8316). Det ble benyttet selvutfylte spørreskjema, utfylt på skolen. Antall fullverdige datasett er 7329 (88,13%). Variabelen ¿lese-/skrivevansker¿ ble dikotomisert slik at elever med store/middels lese-/skrivevansker ble betraktet som én gruppe, versus elever med lette/ingen lese-/skrivevansker. Data er behandlet med statistikkprogrammet SPSS, og det er utført multivariate analyser ved hjelp av logistisk regresjon (justert odds ratio; 95% C.I.). Resultater: Forekomsten av lese-/skrivevansker i materialet var 20,4%, omtrent som forventet. 9.3% hadde store/middels lese-/skrivevansker. Følgende faktorer var assosiert med store/middels lese-/skrivevansker: Gutter (1.93; 1.54, 2.42), store konsentrasjonsvansker (1.49; 1.15, 1.94), store vansker med å forstå læreren (1.80; 1.34, 2.42), og opplevd mobbing (1.94; 1.51, 2.49). Assosiert med dårlig akademisk mestring var først og fremst store/middels lese-/skrivevansker (4.50; 3.24, 6.26) og lave utdanningsambisjoner (11.44; 9.05, 14.46), samt bl.a.: gutter (1.77; 1.51, 2.06), utenlandske foreldre (2.43; 1.96, 3.01), opplevd mobbing (1.26; 1.02, 1.57) og lite selvopplevd sosial støtte fra lærere (1.44; 1.23, 1.68). Det var ingen signifikant assosiasjon mellom store/middels lese-/skrivevansker og opplevelse av lite sosial støtte fra medelever (1.05; 0.80, 1.37) eller lærere (0.79; 0.60, 1.04). Konklusjon: Lese-/skrivevansker er assosiert med dårlig akademisk mestring, men viser ingen sammenheng med (selvopplevd) sosial støtte fra medelever og lærere.

• Green, Kristian; Oppedal, Brit; Wilmar, Bente; Stang, Grete Hovind & Bjertness, Espen (2002). Akademisk og sosial mestring hos elever med lese-/skrivevansker. Full text in Research Archive Show summary

  Hva karakteriserer ungdom med lese-/skrivevansker? Opplever ungdom med lese-/skrive-vansker støtte fra medelever og lærere, og klarer de seg faglig? Denne studien baserer seg på data fra Helseundersøkelsen i Oslo 2000-2001, med selvutfylte spørreskjema, utfylt av 7329 10.-klassinger i 1999/00 & 2000/01. Konklusjoner: Lese-/skrivevansker er assosiert med 1) gutter, 2) gj.sn.karakter<3.00 (svakere assosiasjon for elever med utenlandske foreldre), 3) psykiske plager og egenvurdert helse (særlig for jenter og elever med utenlandske foreldre), 4) region indre vest og indre øst (ikke for gutter eller elever med utenlandske foreldre). Elever med lese-/skrivevansker oppgir omtrent samme grad av sosial støtte fra medelever og lærere som elever uten lese-/skrivevansker.

• Green, Kristian; Oppedal, Brit; Wilmar, Bente; Stang, Grete Hovind & Bjertness, Espen (2002). Akademisk mestring og sosial støtte fra medelever og lærere hos elever med lese-/skrivevansker. Full text in Research Archive

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