Serum long chain n-3 fatty acids (EPA and DHA) in the pregnant mother are independent of risk of type 1 diabetes in the offspring I. M. Sørensen 1 * G. Joner 1,2 P. A. Jenum 3 A. Eskild 4,5 L. C. Stene 6 1 Department of Paediatrics, Oslo University Hospital Ullevål, Oslo, Norway 2 Department of Health Management and Health Economics, Institute of Health and Society, Oslo, Norway 3 Department of Medical Microbiology, Vestre Viken Hospital Trust, Oslo, Norway 4 Department of Obstetrics and Gynaecology, Akershus University Hospital, Oslo, Norway 5 Institute of Clinical Medicine, University of Oslo, Oslo, Norway 6 Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway *Correspondence to: Ingvild Menes Sørensen, Department of Paediatrics, Oslo University Hospital Ullevål, P. O. Box 4956 Nydalen, N-0424 Oslo, Norway. E-mail: i.m.sorensen@medisin.uio.no Abstract Background This article aims to study whether higher proportions of the long chain n-3 fatty acids eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) in the phospholipid fraction of serum samples in pregnancy were associated with a lower risk of childhood onset type 1 diabetes in the offspring. Methods In a prospective cohort of nearly 30 000 pregnant women who gave birth in Norway during 1992–1994, we analysed serum samples from 89 women whose child developed type 1 diabetes and was included in the nationwide Norwegian Childhood Diabetes Registry and 125 randomly selected women whose child did not develop type 1 diabetes before 15 years of age. Specific fatty acids were expressed as the proportion of total fatty acids (g/100 g) in the phospholipid fraction in serum analysed using solid phase extraction and gas chromatography with flame ionization detection. Results There was no significant association between EPA or DHA in maternal serum and risk of type 1 diabetes in the offspring. Odds ratio (OR) for upper versus lower quartile of EPA was 0.75 [95% confidence interval (CI) 0.34–1.65], test for trend p = 0.4, and for DHA OR = 0.71 (95% CI 0.33–1.53), test for trend p = 0.6. No significant association was found for the sum of n-3 fatty acids, or for n-6/n-3 ratio in the mother with risk of type 1 diabetes in the offspring. Conclusions Our data did not support the hypothesis that higher proportions of maternal EPA or DHA during pregnancy are associated with a lower risk of type 1 diabetes in the offspring. Copyright © 2012 John Wiley & Sons, Ltd. Keywords type 1 diabetes; fatty acids; biomarkers; pregnancy; immunology; human; epidemiology Abbreviations DHA, docosahexaenoic acid; EPA, eicosapentaenoic acid; PUFA, polyunsaturated fatty acids; HLA, human leukocyte antigen Introduction Type 1 diabetes is one of the most common chronic diseases in childhood, and the incidence has increased in most countries over the past two–three decades [1]. Norway is among the countries with the highest incidence rates of type 1 diabetes among children [2]. The disease is characterized by selective destruc- tion of insulin producing beta cells in the pancreas, probably mediated by Th1 cells [3]. Autoantibodies towards islet antigens are present in serum from months to years before clinical manifestation [4,5] and can occur as early as 6 months of age [6]. Multiple genes are involved in the aetiology of the Received: 8 July 2011 Revised: 7 February 2012 Accepted: 12 February 2012 RESEARCH ARTICLE Copyright © 2012 John Wiley & Sons, Ltd. DIABETES/METABOLISM RESEARCH AND REVIEWS Diabetes Metab Res Rev 2012; 28: 431–438. Published online in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/dmrr.2293