Applied nutritional investigation Dietary vitamin D intake and prevalence of depressive symptoms during pregnancy in Japan Yoshihiro Miyake M.D., Ph.D. a, * , Keiko Tanaka D.D.S., Ph.D. b , Hitomi Okubo Ph.D. c , Satoshi Sasaki M.D., Ph.D. d , Masashi Arakawa Ph.D. e a Department of Public Health, Ehime University Graduate School of Medicine, Ehime, Japan b Department of Preventive Medicine and Public Health, Faculty of Medicine, Fukuoka University, Fukuoka, Japan c Department of Health Promotion, National Institute of Public Health, Saitama, Japan d Department of Social and Preventive Epidemiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan e Health Tourism Research Center, Graduate School of Tourism Sciences, University of the Ryukyus, Okinawa, Japan article info Article history: Received 22 April 2014 Accepted 23 June 2014 Keywords: Depressive symptoms Intake Japanese Pregnancy Vitamin D abstract Objective: Although the relationship between vitamin D levels and depressive symptoms has been explored, the results are inconsistent. Epidemiologic evidence concerning the relationship between dietary vitamin D intake and depressive symptoms in pregnancy is nonexistent. The aim of this current cross-sectional study was to examine this issue in Japan. Methods: The study included 1745 pregnant women. Depressive symptoms were defined as present when women had a Center for Epidemiologic Studies Depression Scale score of 16 or higher. Di- etary intake during the preceding month was assessed using a self-administered diet history questionnaire. Adjustment was made for age, gestation, region of residence, number of children, family structure, history of depression, family history of depression, smoking, secondhand smoke exposure at home and at work, job type, household income, education, body mass index, intake of saturated fatty acids, and intake of eicosapentaenoic acid plus docosahexaenoic acid. Results: The prevalence of depressive symptoms during pregnancy was 19.3%. Higher dietary vitamin D intake was significantly associated with a lower prevalence of depressive symptoms during pregnancy, independent of potential dietary and nondietary confounding factors. Multi- variate odds ratios (95% confidence intervals) for depressive symptoms during pregnancy in the first, second, third, and fourth quartiles of assessed intake of vitamin D were 1 (reference), 0.79 (0.55–1.11), 0.73 (0.49–1.07), and 0.52 (0.30–0.89), respectively (P for trend ¼ 0.02). Conclusion: The current cross-sectional study in Japan suggests that higher vitamin D intake may be associated with a lower prevalence of depressive symptoms during pregnancy. Ó 2015 Elsevier Inc. All rights reserved. Introduction Vitamin D recently has attracted widespread interest not only for its importance in bone health but also for its association with reduced risk for many chronic diseases such as autoimmune diseases, type 2 diabetes, heart disease, many cancers, and in- fectious diseases [1]. The association between vitamin D levels and depressive symptoms has been explored: Several studies have shown a significant inverse association between serum 25- hydroxyvitamin D [25(OH)D] levels and depressive symptoms [2–6], whereas others have reported a null relationship between 25(OH)D and depressive symptoms [7–10]. Vitamin D deficiency is pandemic worldwide [1]. In Japan, vitamin D status is poorer in young women than in women of middle and advanced ages [11]. Hypovitaminosis D is common in pregnancy because of the requirements of the fetus. If a rela- tionship exists between hypovitaminosis D and depressive symptoms, pregnant women may be more susceptible to depressive symptoms for this reason. To our knowledge, only two epidemiologic studies, one conducted in the Netherlands and the This research was supported by JSPS KAKENHI Grant Numbers 19590606, 20791654, 21590673, 22592355,22119507, 24390158, 25463275, and 25670305, by Health and Labour Sciences Research Grants for Research on Allergic Disease and Immunology and Health Research on Children, Youth and Families from the Ministry of Health, Labour and Welfare, Japan, by Meiji Co. Ltd., and by the Food Science Institute Foundation. YM, KT, and MA contributed to the study concept and design and the acquisition of data. HO and SS were responsible for the estimation of dietary factors. YM was responsible for the analysis and inter- pretation of data and the drafting of the manuscript. * Corresponding author. Tel.: þ81 89 960 5281; fax: þ81 89 960 5284. E-mail address: miyake.yoshihiro.ls@ehime-u.ac.jp (Y. Miyake). 0899-9007/$ - see front matter Ó 2015 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.nut.2014.06.013 Contents lists available at ScienceDirect Nutrition journal homepage: www.nutritionjrnl.com Nutrition 31 (2015) 160–165