Association of folate, vitamin B-12 and vitamin B-6 intake with diabetes and prediabetes in adults aged 20 years and older.

BACKGROUND AND OBJECTIVES: This study aimed to assess the association of folate, vitamin B-12 and vitamin B-6 from diet and supplements with diabetes and prediabetes in U.S. adults. METHODS AND STUDY DESIGN: We used data from the National Health and Nutrition Examination Survey (NHANES) 2007-2016 to conduct this crosssectional study. Diabetes and prediabetes status were based on self-report, medication use, fasting plasma glucose levels (FPG), haemoglobin A1c (HbA1c) levels and the two hours plasma glucose (PG) value during a 75-g oral glucose tolerance test (OGTT). Logistic regression models and restricted cubic spline models were used to evaluate the associations between dietary folate, vitamin B-12, vitamin B-6 and diabetes. RESULTS: After adjustment for the potential confounders, compared with the lowest quartile, the ORs (odds ratios) with 95%CIs (confidence intervals) of diabetes for the highest quartile intakes of folate and vitamin B-6 were 0.65 (0.47-0.90) and 0.61 (0.42-0.89), the OR with 95% CI of diabetes for the third quartile of dietary vitamin B-12 was 0.76 (0.60-0.97). Further excluded participants with diabetes history, the ORs with 95% CI of newly diagnosed diabetes were 0.60 (0.39-0.94), 0.84 (0.58-1.23), and 0.65 (0.43-0.98) for the third quartile of dietary folate, vitamin B-12 and vitamin B-6, respectively. A linear inverse relationship was found between vitamin B12 and diabetes, and a nonlinear inverse relationship was found between dietary folate, dietary vitamin B6 and diabetes. CONCLUSIONS: Our study suggested that folate, vitamin B-12 and vitamin B-6 intake were inversely associated with the risk of diabetes in US adults.