Magne Thoresen

• Zhang, Chi; Eken, Torsten; Jørgensen, Silje Bakken; Thoresen, Magne & Søvik, Signe (2022). Effects of patient-level risk factors, departmental allocation and seasonality on intrahospital patient transfer patterns: network analysis applied on a Norwegian single-centre data set. BMJ Open. ISSN 2044-6055. 12(3). doi: 10.1136/bmjopen-2021-054545.
• Djordjilović, Vera; Hemerik, Jesse & Thoresen, Magne (2022). On optimal two-stage testing of multiple mediators. Biometrical Journal. ISSN 0323-3847. p. 1–19. doi: 10.1002/bimj.202100190.
• Konglevoll, Dina Moxness; Hjartåker, Anette; Hopstock, Laila Arnesdatter; Strand, Bjørn Heine; Thoresen, Magne & Andersen, Lene Frost [Show all 7 contributors for this article] (2022). Protein Intake and the Risk of Pre-Frailty and Frailty in Norwegian Older Adults. The Tromsø Study 1994–2016. Journal of Frailty & Aging (JFA). ISSN 2260-1341. p. 1–11. doi: 10.14283/jfa.2022.16.
• Zhang, Chi; Fanaee-T, Hadi & Thoresen, Magne (2021). Feature extraction from unequal length heterogeneous EHR time series via dynamic time warping and tensor decomposition. Data mining and knowledge discovery. ISSN 1384-5810. 35, p. 1760–1784. doi: 10.1007/s10618-020-00724-6.
• Ghosh, Abhik & Thoresen, Magne (2021). Consistent fixed-effects selection in ultra-high dimensional linear mixed models with error-covariate endogeneity. Statistica sinica. ISSN 1017-0405. 31(3), p. 2073–2102. doi: 10.5705/ss.202019.0421.
• Shaikh, Fareeha; Kjøllesdal, Marte Karoline Råberg; Carslake, David; Thoresen, Magne & Næss, Øyvind Erik (2021). Cardiovascular risk factors in extended family members and birthweight in offspring. Journal of Developmental Origins of Health and Disease. ISSN 2040-1744. doi: 10.1017/S2040174421000076.
• Larsen, Sunniva Veen; Holven, Kirsten B.; Christensen, Jacob J.; Flatberg, Arnar; Rundblad, Amanda & Leder, Lena [Show all 13 contributors for this article] (2021). Replacing Saturated Fat with Polyunsaturated Fat Modulates Peripheral Blood Mononuclear Cell Gene Expression and Pathways Related to Cardiovascular Disease Risk Using a Whole Transcriptome Approach. Molecular Nutrition & Food Research. ISSN 1613-4125. 65(24). doi: 10.1002/mnfr.202100633. Full text in Research Archive
• Bøhn, Siv Kjølsrud; Myhrstad, Mari; Thoresen, Magne; Erlund, Iris; Vasstrand, Ann Kristin & Marciuch, Anne [Show all 11 contributors for this article] (2021). Bilberry/red grape juice decreases plasma biomarkers of inflammation and tissue damage in aged men with subjective memory impairment –a randomized clinical trial. BMC Nutrition. ISSN 2055-0928. 7. doi: 10.1186/s40795-021-00482-8. Full text in Research Archive
• Ghosh, Abhik & Thoresen, Magne (2021). A robust variable screening procedure for ultra-high dimensional data. Statistical Methods in Medical Research. ISSN 0962-2802. 30(8), p. 1816–1832. doi: 10.1177/09622802211017299. Full text in Research Archive
• Ponzi, Erica; Thoresen, Magne; Nøst, Therese Haugdahl & Møllersen, Kajsa (2021). Integrative, multi-omics, analysis of blood samples improves model predictions: applications to cancer. BMC Bioinformatics. ISSN 1471-2105. 22(1), p. 1–17. doi: 10.1186/s12859-021-04296-0. Full text in Research Archive
• Hemerik, Jesse; Thoresen, Magne & Finos, Livio (2021). Permutation testing in high-dimensional linear models: an empirical investigation. Journal of Statistical Computation and Simulation. ISSN 0094-9655. 91(5), p. 897–914. doi: 10.1080/00949655.2020.1836183. Full text in Research Archive
• Stolt, Emma Theresia Kjelland; Olsen, Thomas; Elshorbagy, Amany; Kozich, Viktor; Van Greevenbroek, Marleen M.J. & Øvrebø, Bente [Show all 10 contributors for this article] (2021). Sulfur amino acid restriction, energy metabolism and obesity: a study protocol of an 8-week randomized controlled dietary intervention with whole foods and amino acid supplements. Journal of Translational Medicine. ISSN 1479-5876. 19. doi: 10.1186/s12967-021-02824-3. Full text in Research Archive
• Christensen, Jacob Juel; Ulven, Stine Marie; Thoresen, Magne; Westerman, Kenneth; Holven, Kirsten Bjørklund & Andersen, Lene Frost (2020). Associations between dietary patterns and gene expression pattern in peripheral blood mononuclear cells: A cross-sectional study. NMCD. Nutrition Metabolism and Cardiovascular Diseases. ISSN 0939-4753. 30(11), p. 2111–2122. doi: 10.1016/j.numecd.2020.06.018. Full text in Research Archive Show summary

  Background and aims Diet may alter gene expression in immune cells involved in atherosclerotic cardiovascular disease susceptibility. However, we still lack a robust understanding of the association between diet and immune cell-related gene expression in humans. Therefore, we examined associations between dietary patterns (DPs) and gene expression profiles in peripheral blood mononuclear cells (PBMCs) in a population of healthy, Norwegian adults (n = 130 women and 105 men). Methods and results We used factor analysis to define a posteriori DPs from food frequency questionnaire-based dietary assessment data. In addition, we derived interpretable features from microarray-based gene expression data (13 967 transcripts) using two algorithms: CIBERSORT for estimation of cell subtype proportions, and weighted gene co-expression network analysis (WGCNA) for cluster discovery. Finally, we associated DPs with either CIBERSORT-predicted PBMC leukocyte distribution or WGCNA gene clusters using linear regression models. We detected three DPs that broadly reflected Western, Vegetarian, and Low carbohydrate diets. CIBERSORT-predicted percentage of monocytes associated negatively with the Vegetarian DP. For women, the Vegetarian DP associated with a large gene cluster consisting of 600 genes mainly involved in regulation of DNA transcription, whereas for men, the Western DP inversely associated with a smaller cluster of 36 genes mainly involved in regulation of metabolic and inflammatory processes. A subsequent protein–protein interaction network analysis suggested that genes within these clusters might physically interact in biological networks. Conclusions Although the present findings are exploratory, our analysis pipeline serves as a useful framework for studying the association between diet and gene expression.

• Fanaee-T, Hadi & Thoresen, Magne (2020). Iterative Multi-mode Discretization: Applications to Co-clustering. Lecture Notes in Computer Science (LNCS). ISSN 0302-9743. 12323, p. 94–105. doi: 10.1007/978-3-030-61527-7_7. Full text in Research Archive
• Rundblad, Amanda; Holven, Kirsten Bjørklund; Øyri, Linn Kristin Lie; Hansson, Patrik; Ivan, Ingvild Hansen & Gjevestad, Gyrd Omholt [Show all 8 contributors for this article] (2020). Intake of fermented dairy products induces a less pro-inflammatory postprandial peripheral blood mononuclear cell gene expression response than non-fermented dairy products: A randomized controlled cross-over trial. Molecular Nutrition & Food Research. ISSN 1613-4125. 64(21), p. 1–11. doi: 10.1002/mnfr.202000319. Full text in Research Archive
• Kollerud, Ruby Del Risco; Cannon-Albright, LA; Haugnes, Hege Sagstuen; Ruud, Ellen; Thoresen, Magne & Nafstad, Per [Show all 9 contributors for this article] (2020). Childhood central nervous system tumors and leukemia: Incidence and familial risk. A comparative population-based study in Utah and Norway. Pediatric Blood & Cancer. ISSN 1545-5009. Aug;67(8):e28408. doi: 10.1002/pbc.28408. Full text in Research Archive
• Irgens, Ingebjørg; Hoff, Jana Midelfart; Jelnes, Rolf; Alexander, Marcalee; Stanghelle, Johan K & Thoresen, Magne [Show all 7 contributors for this article] (2020). Spinal cord injury and development of pressure injury during acute rehabilitation in Norway: a national retrospective cross-sectional study. Spinal Cord. ISSN 1362-4393. 58, p. 1069–1079. doi: 10.1038/s41393-020-0465-z. Full text in Research Archive
• Page, Christian; Djordjilovic, Vera; Nøst, Therese Haugdahl; Ghiasvand, Reza; Sandanger, Torkjel M & Frigessi Di Rattalma, Arnoldo [Show all 8 contributors for this article] (2020). Lifetime ultraviolet radiation exposure and DNA methylation in blood leukocytes: The Norwegian Women and Cancer Study. Scientific Reports. ISSN 2045-2322. 10, p. 1–8. doi: 10.1038/s41598-020-61430-3. Full text in Research Archive
• Rosseland, Leiv Arne; Reme, Silje Endresen; Simonsen, Tone Breines; Thoresen, Magne; Nielsen, Christopher Sivert & Eberhard-Gran, Malin (2020). Are labor pain and birth experience associated with persistent pain and postpartum depression? A prospective cohort study. Scandinavian Journal of Pain. ISSN 1877-8860. 20(3), p. 591–602. doi: 10.1515/sjpain-2020-0025. Full text in Research Archive
• Kjeverud, Anita; Østlie, Kristin; Schanke, Anne-Kristine; Gay, Caryl; Thoresen, Magne & Lerdal, Anners (2020). Trajectories of fatigue among stroke patients from the acute phase to 18 months post-injury: A latent class analysis. PLOS ONE. ISSN 1932-6203. 15(4), p. 1–14. doi: 10.1371/journal.pone.0231709. Full text in Research Archive Show summary

  Using GMM, three latent classes of fatigue trajectories over 18 months were identified, characterized by differing levels of fatigue: low, moderate and high. The mean FSS score for each class remained relatively stable across all four time points. In the univariate analyses, age

• Kollerud, Ruby Del Risco; Haugnes, Hege Sagstuen; Claussen, Bjørgulf; Thoresen, Magne; Nafstad, Per & Farnham, James [Show all 9 contributors for this article] (2020). A population-based study of testicular cancer risk among children and young adults from Norway and Utah, USA. International Journal of Cancer. ISSN 0020-7136. 147(6). doi: 10.1002/ijc.32949. Full text in Research Archive
• Christensen, Jacob Juel; Ulven, Stine Marie; Thoresen, Magne; Westerman, Kenneth; Holven, Kirsten Bjørklund & Andersen, Lene Frost (2020). Associations between dietary patterns and gene expression pattern in peripheral blood mononuclear cells: a cross-sectional study (preprint). bioRxiv - the preprint server for biology. doi: 10.1101/2020.01.25.20018465.
• Myhrvold, Birgitte Lawaetz; Kongsted, Alice; Irgens, Pernille Marie; Robinson, Hilde Stendal; Thoresen, Magne & Vøllestad, Nina Køpke (2019). Broad External Validation and Update of a Prediction Model for Persistent Neck Pain After 12 Weeks. Spine. ISSN 0362-2436. 44(22), p. E1298–E1310. doi: 10.1097/BRS.0000000000003144. Full text in Research Archive
• Hansson, Patrik; Holven, Kirsten Bjørklund; Øyri, Linn Kristin Lie; Brekke, Hilde Kristin; Gjevestad, Gyrd Omholt & Thoresen, Magne [Show all 7 contributors for this article] (2019). Sex differences in postprandial responses to different dairy products on lipoprotein subclasses: A randomised controlled cross-over trial. British Journal of Nutrition. ISSN 0007-1145. 122(7), p. 780–789. doi: 10.1017/S0007114519001429. Full text in Research Archive
• Øyri, Linn Kristin Lie; Narverud, Ingunn; Bogsrud, Martin Prøven; Hansson, Patrik; Leder, Lena & Byfuglien, Marte Gjeitung [Show all 10 contributors for this article] (2019). Postprandial changes in gene expression of cholesterol influx and efflux mediators after intake of SFA compared to n-6 PUFA in subjects with and without familial hypercholesterolemia – secondary outcomes of a randomized controlled trial. Journal of Nutritional Science (JNS). ISSN 2048-6790. 8:e27, p. 1–27. doi: 10.1017/jns.2019.25. Full text in Research Archive Show summary

  The long-term cholesterol lowering effect of replacing intake of saturated fatty acids (SFAs) with polyunsaturated fatty acids (PUFAs) is well established, however not fully explained mechanistically. We examined the postprandial response of meals with different fat quality on expression of lipid genes in peripheral blood mononuclear cells (PBMC) in subjects with and without familial hypercholesterolemia (FH). Thirteen subjects with FH (who had discontinued lipid-lowering treatment ≥4 weeks prior to both test days) and 14 normolipidemic controls were included in a randomized controlled double-blind crossover study with two meals, each with 60 grams of fat either mainly SFAs (~40 E%) or n-6 PUFAs (~40 E%). PBMCs were isolated in fasting, and 4 and 6 hours postprandial blood samples. Expression of 33 lipid genes was analysed by reverse transcription quantitative polymerase chain reaction. A linear mixed model was used to assess postprandial effects between meals and groups. There was a significant interaction between meal and group for MSR1 (p=0.03), where intake of SFAs compared to n-6 PUFAs induced a larger reduction in gene expression in controls only (p=0.01). Intake of SFAs compared to n-6 PUFAs induced larger reduction in gene expression levels of LDLR and FADS1/2, smaller increase of INSIG1 and FASN, and larger increase of ABCA1 and ABCG1 (p=0.01 for all, no group interaction). Intake of SFAs compared to n-6 PUFAs induced changes in gene expression of cholesterol influx and efflux mediators in PBMCs including lower LDLR and higher ABCA1/G1, potentially explaining the long-term cholesterol-raising effect of a high SFA intake.

• Hjemsæter, Arne Jan; Bramness, Jørgen Gustav; Drake, Robert; Skeie, Ivar; Monsbakken, Bent Berntsen & Thoresen, Magne [Show all 7 contributors for this article] (2019). Predictors of problematic substance use 18 years after treatment: a longitudinal cohort study of persons with substance use disorders. Cogent Psychology. ISSN 2331-1908. 6:1634325, p. 1–13. doi: 10.1080/23311908.2019.1634325. Full text in Research Archive
• Hansson, Patrik; Holven, Kirsten Bjørklund; Øyri, Linn Kristin Lie; Brekke, Hilde Kristin; Biong, Anne Sofie & Gjevestad, Gyrd Omholt [Show all 10 contributors for this article] (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), p. 422–431. doi: 10.1093/jn/nxy291. Full text in Research Archive
• Rundblad, Amanda; Larsen, Sunniva; Myhrstad, Mari; Ottestad, Inger; Thoresen, Magne & Holven, Kirsten Bjørklund [Show all 7 contributors for this article] (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), p. 1–13. doi: 10.1186/s12263-019-0633-y. Full text in Research Archive
• 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), p. 1625–1633. doi: 10.1093/bioinformatics/bty847.
• 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), p. 2031–2050. doi: 10.1080/00949655.2019.1607345. Full text in Research Archive
• Djordjilovic, Vera; Page, Christian Magnus; Gran, Jon Michael; Nøst, Therese Haugdahl; Sandanger, Torkjel M & Veierød, Marit Bragelien [Show all 7 contributors for this article] (2019). Global test for high-dimensional mediation: Testing groups of potential mediators. Statistics in Medicine. ISSN 0277-6715. 38(18), p. 3346–3360. doi: 10.1002/sim.8199. Full text in Research Archive
• Tork, Hadi Fanaee & Thoresen, Magne (2019). Performance evaluation of methods for integrative dimension reduction. Information Sciences. ISSN 0020-0255. 493, p. 105–119. doi: 10.1016/j.ins.2019.04.041. Full text in Research Archive
• Thoresen, Magne (2019). Spurious interaction as a result of categorization 01 Mathematical Sciences 0104 Statistics. BMC Medical Research Methodology. ISSN 1471-2288. 19(1), p. 1–8. doi: 10.1186/s12874-019-0667-2. Full text in Research Archive
• Kollerud, Ruby Del Risco; Ruud, Ellen; Haugnes, Hege Sagstuen; Cannon-Albright, Lisa A.; Thoresen, Magne & Nafstad, Per [Show all 10 contributors for this article] (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, p. 1007–1014. doi: 10.1038/s41416-019-0445-2. Full text in Research Archive
• Thoresen, Magne (2018). Er effekten forskjellig blant kvinner og menn? . Tidsskrift for Den norske legeforening. ISSN 0029-2001. 138. doi: 10.4045/tidsskr.18.0602.
• Thoresen, Magne (2018). Konfundering – et tilbakevendende problem . Tidsskrift for Den norske legeforening. ISSN 0029-2001. 138. doi: 10.4045/tidsskr.17.0795.
• 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 (JCGS). ISSN 1061-8600. 27(4), p. 739–749. doi: 10.1080/10618600.2018.1425626. Full text in Research Archive 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.

• 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), p. 135–144. doi: 10.1111/biom.12730. 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.
• 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. p. 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, p. 581–597. doi: 10.1111/sjos.12264. Full text in Research Archive
• 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), p. 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), p. 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. [Show all 27 contributors for this article] (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.
• Tjelle, Torunn Elisabeth; Holtung, Linda; Bøhn, Siv Kjølsrud; Aaby, Kjersti; Thoresen, Magne & Wiik, Siv Åshild [Show all 11 contributors for this article] (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), p. 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.

• 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), p. 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), p. 809–829. doi: 10.5705/ss.2013.180. Full text in Research Archive
• Hellton, Kristoffer Herland & Thoresen, Magne (2014). The Impact of Measurement Error on Principal Component Analysis. Scandinavian Journal of Statistics. ISSN 0303-6898. 41(4), p. 1051–1063. doi: 10.1111/sjos.12083. Full text in Research Archive
• Myhrstad, Mari; Ulven, Stine Marie; Günther, Clara-Cecilie; Ottestad, Inger; Holden, Marit & Ryeng, Einar [Show all 11 contributors for this article] (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), p. 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; 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), p. 837–845. doi: 10.1111/jcpe.12278.
• Skeie, Ivar; Brekke, Mette; Clausen, Thomas; Gossop, Michael; Lindbæk, Morten & Reinertsen, Even [Show all 8 contributors for this article] (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), p. 194–201. doi: 10.1159/000345229.
• 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), p. 556–557.
• 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
• Bøhn, Siv Kjølsrud; Russnes, Kjell Magne; Sakhi, Amrit Kaur; Thoresen, Magne; Holden, Marit & Moskaug, Jan Øivind [Show all 10 contributors for this article] (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), p. 543–546. doi: 10.2340/00015555-1251.
• Mdala, Ibrahimu; Haffajee, Anne D; Socransky, Sigmund S; De Blasio, Birgitte Freiesleben; Thoresen, Magne & Olsen, Ingar [Show all 7 contributors for this article] (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.
• Skeie, Ivar; Brekke, Mette; Gossop, Michael; Lindbæk, Morten; Reinertsen, Even & Thoresen, Magne [Show all 7 contributors for this article] (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.
• 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.
• 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), p. 363–370. doi: 10.1038/jid.2010.264.
• 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, p. 363–370. doi: 10.1038/jid.2010.264.
• Bøhn, Siv Kjølsrud; Myhrstad, Mari Charlotte; Thoresen, Magne; Holden, Marit; Karlsen, Anette & Tunheim, Siv Haugen [Show all 17 contributors for this article] (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.
• 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), p. 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), p. 705–713. doi: 10.1007/s00787-010-0106-8.
• Sakhi, Amrit Kaur; Bøhn, Siv Kjølsrud; Smeland, Sigbjørn; Thoresen, Magne; Berge, Guro & Tausjø, Johan Elling [Show all 11 contributors for this article] (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), p. 322–328. doi: 10.1080/01635580903441188.
• 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), p. 39–44. doi: 10.2340/00015555-0554.
• 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), p. 1356–1362. doi: 10.1111/j.1360-0443.2009.02570.x.
• Sakhi, Amrit Kaur; Russnes, Kjell Magne; Thoresen, Magne; Bastani, Nasser Ezzatkhah; Karlsen, Anette & Smeland, Sigbjørn [Show all 7 contributors for this article] (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).
• 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.
• 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.
• 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), p. 3386–3410. doi: 10.1002/sim.3712.
• Karlsen, Anette; Svendsen, Mette; Brevik, Asgeir; Bøhn, Siv K; Myhrstad, Mari C.W. & Thoresen, Magne [Show all 19 contributors for this article] (2008). Dietary intake of antioxidant-rich foods increase plasma antioxidants, enhance DNA repair capacity and reduce blood pressure in smoking, middle-aged men, PhD Thesis. Universitetet i Oslo, Institutt for ernæringsforskning.
• 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, p. 573–577. doi: 10.2340/00015555-0505.
• 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.

• 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.
• Laake, Petter; Thoresen, Magne & Veierød, Marit Bragelien (2007). Målefeilsproblemer. In Laake, Petter; Hjartåker, Anette; Thelle, Dag Steinar & Veierød, Marit Bragelien (Ed.), Epidemiologiske og kliniske forskningsmetoder. Gyldendal Akademisk. ISSN 978-82-05-33505-9. p. 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, p. 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, p. 465–471. doi: 10.1093/aje/kwm107.
• 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, p. 68–78.
• 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, p. 683–694. doi: 10.1080/10629360600589541.

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• Christensen, Jacob Juel; Ulven, Stine Marie; Thoresen, Magne; Westerman, Kenneth; Holven, Kirsten Bjørklund & Andersen, Lene Frost (2020). Associations between dietary patterns and gene expression pattern in PBMCs: a cross-sectional study.
• Rosseland, Leiv Arne; Reme, Silje Endresen; Simonsen, Tone Breines; Thoresen, Magne; Nielsen, Christopher Sivert & Eberhard-Gran, Malin (2020). Corrigendum to: Are labor pain and birth experience associated with persistent pain and postpartum depression? A prospective cohort study. Scandinavian Journal of Pain. ISSN 1877-8860. 20(4), p. 865–865. doi: 10.1515/sjpain-2020-2023.
• Rundblad, Amanda; Larsen, Sunniva Veen; Myhrstad, Mari; Ottestad, Inger; Thoresen, Magne & Holven, Kirsten Bjørklund [Show all 7 contributors for this article] (2019). Characterization of PBMC gene expression and lipoprotein subclasses among plasma TG responders and non-responders.
• Thoresen, Magne (2019). Det problematiske oddsforholdet. Tidsskrift for Den norske legeforening. ISSN 0029-2001. 139(7). doi: 10.4045/tidsskr.19.0011.
• Larsen, Sunniva Veen; Holven, Kirsten Bjørklund; Flatberg, Arnar; Christensen, Jacob J.; Leder, Lena & Blomhoff, Rune [Show all 11 contributors for this article] (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.
• Hansson, Patrik; Holven, Kirsten Bjørklund; Øyri, Linn Kristin Lie; Brekke, Hilde Kristin; Gjevestad, Gyrd Omholt & Thoresen, Magne [Show all 7 contributors for this article] (2018). SEX DIFFERENCES IN POSTPRANDAL RESPONSE TO DIFFERENT DAIRY PRODUCTS ON LIPOPROTEIN SUBCLASSES: A RANDOMIZED CONTROLLED CROSS-OVER TRIAL.
• Hansson, Patrik; Holven, Kirsten Bjørklund; Øyri, Linn Kristin Lie; Brekke, Hilde Kristin; Biong, Anne Sofie & Gjevestad, Gyrd Omholt [Show all 8 contributors for this article] (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 [Show all 8 contributors for this article] (2018). Postprandial effects of different dairy products on triglycerides in lean and overweight subjects: a randomized controlled cross-over study.
• Rundblad, Amanda; Larsen, Sunniva Veen; Myhrstad, Mari; Ottestad, Inger; Thoresen, Magne & Holven, Kirsten Bjørklund [Show all 7 contributors for this article] (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 [Show all 8 contributors for this article] (2017). Postprandial effects of different dairy products on blood lipids in lean and overweight subjects.
• Ørn, Stein & Thoresen, Magne (2015). Growth mixture modeling: the new statistical kid on the block? Journal of Cardiac Failure. ISSN 1071-9164. 21(6), p. 446–447.
• 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.
• 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 [Show all 13 contributors for this article] (2009). Effect of berry and grape polyphenols on cognition and blood parameters in normal, aged men with subjective memory decline.
• 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, p. S174–S174.
• Bøhn, Siv Kjølsrud; Myhrstad, Mari Charlotte; Thoresen, Magne; Holden, Marit; Tunheim, Siv Haugen & Karlsen, Anette [Show all 16 contributors for this article] (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. [Show all 11 contributors for this article] (2008). Effect of berry polyphenols on cognition and clinical parameters in normal, aged men with subjective memory decline. A pilot study.
• Hellton, Kristoffer Herland & Thoresen, Magne (2015). On high-dimensional principal component analysis in genomics: consistency and robustness. Institute Of Basic Medical Sciences, Faculty of Medicine, University of Oslo. ISSN 9788282649513.
• Mdala, Ibrahimu; Haffajee, Anne D; Socransky, Sigmund S; De Blasio, Birgitte Freiesleben; Thoresen, Magne & Goodson, Max J [Show all 7 contributors for this article] (2012). Hvilken type periobehandling gir best kliniske resultater over tid? Det odontologiske fakultet, Universitetet i Oslo.
• 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. Faculty of Medicine, University of Oslo. ISSN 978-82-8264-148-7.

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