Shamima Akter1, Keisuke Kuwahara2, Yumi Matsushita3, Tohru Nakagawa4, Maki Konishi5, Toru Honda4, Shuichiro Yamamoto4, Takeshi Hayashi4, Mitsuhiko Noda6, Tetsuya Mizoue5. 1. Department of Epidemiology and Prevention, Center for Clinical Sciences, National Center for Global Health and Medicine, Tokyo, Japan. Electronic address: sakter@hosp.ncgm.go.jp. 2. Department of Epidemiology and Prevention, Center for Clinical Sciences, National Center for Global Health and Medicine, Tokyo, Japan; Teikyo University Graduate School of Public Health, Tokyo, Japan. 3. Department of Clinical Research Coordination, Center for Clinical Sciences, National Center for Global Health and Medicine, Tokyo, Japan. 4. Hitachi Health Care Center, Hitachi, Ltd., Ibaraki, Japan. 5. Department of Epidemiology and Prevention, Center for Clinical Sciences, National Center for Global Health and Medicine, Tokyo, Japan. 6. Department of Endocrinology and Diabetes, Saitama Medical University, Saitama, Japan.
Abstract
BACKGROUND & AIMS: Increasing evidence has suggested a protective role of vitamin D on diabetes, but epidemiologic evidence is scarce among Asian populations. Here we prospectively examined the association between serum 25-hydroxyvitamin D3 (25[OH]D3) and type 2 diabetes (T2D) risk in Japanese individuals. METHODS: A nested case-control study was conducted in a biomarker cohort of 4754 employees (baseline age 34-69 years) who had attended in a comprehensive health checkup and donated a blood sample. Diabetes diagnosis was based on plasma glucose, glycated hemoglobin, and self-reporting during the 5-year follow-up. Using density sampling, two controls were randomly matched to each case by sex, age, and date of checkup; 336 cases and 668 controls had serum 25(OH)D3 data. Association between serum 25[OH]D3 and the risk of T2D was assessed using conditional logistic regression analysis. RESULTS: Serum 25(OH)D3 was significantly and inversely associated with T2D risk after adjustment for known risk factors other than BMI (OR [highest vs. lowest serum 25(OH)D3 quartile] = 0.58, 95% CI = 0.36-0.92; P for trend = 0.03). This association was somewhat attenuated after additional adjustment for BMI (OR = 0.65, 95% CI = 0.40-1.08; P for trend = 0.08). The inverse association was more evident among individuals whose blood samples were taken during the darker season (OR = 0.45; P for trend = 0.01). In the highest quartile of 25(OH)D3, progression from prediabetes to T2D was about 37% lower than in the lowest quartile. CONCLUSIONS: Higher circulating 25(OH)D3 was associated with a lower risk of T2D, and this association was stronger among individuals whose blood was taken during the darker season and among those with prediabetes.
BACKGROUND & AIMS: Increasing evidence has suggested a protective role of vitamin D on diabetes, but epidemiologic evidence is scarce among Asian populations. Here we prospectively examined the association between serum 25-hydroxyvitamin D3 (25[OH]D3) and type 2 diabetes (T2D) risk in Japanese individuals. METHODS: A nested case-control study was conducted in a biomarker cohort of 4754 employees (baseline age 34-69 years) who had attended in a comprehensive health checkup and donated a blood sample. Diabetes diagnosis was based on plasma glucose, glycated hemoglobin, and self-reporting during the 5-year follow-up. Using density sampling, two controls were randomly matched to each case by sex, age, and date of checkup; 336 cases and 668 controls had serum 25(OH)D3 data. Association between serum 25[OH]D3 and the risk of T2D was assessed using conditional logistic regression analysis. RESULTS: Serum 25(OH)D3 was significantly and inversely associated with T2D risk after adjustment for known risk factors other than BMI (OR [highest vs. lowest serum 25(OH)D3 quartile] = 0.58, 95% CI = 0.36-0.92; P for trend = 0.03). This association was somewhat attenuated after additional adjustment for BMI (OR = 0.65, 95% CI = 0.40-1.08; P for trend = 0.08). The inverse association was more evident among individuals whose blood samples were taken during the darker season (OR = 0.45; P for trend = 0.01). In the highest quartile of 25(OH)D3, progression from prediabetes to T2D was about 37% lower than in the lowest quartile. CONCLUSIONS: Higher circulating 25(OH)D3 was associated with a lower risk of T2D, and this association was stronger among individuals whose blood was taken during the darker season and among those with prediabetes.