OBJECTIVE: The goal of this study was to examine whether maternal dietary intake of vitamin D, omega-3 fatty acids, and omega-6 fatty acids during pregnancy is associated with the appearance of islet autoimmunity (IA) in offspring.

RESEARCH DESIGN AND METHODS: The Diabetes Autoimmunity Study in the Young (DAISY) is recruiting at birth and following children at increased risk for type 1 diabetes, as determined by HLA-DR genotype or by family history of type 1 diabetes. A total of 233 mothers of newly recruited DAISY subjects were asked to recall their intake of food and nutritional supplements during the third trimester of pregnancy using the Willett food frequency questionnaire. Children were followed for an average of 4 years (range 0.8-7.3 years) for the appearance of insulin, GAD(65), and IA-2 autoantibodies. Sixteen children developed at least one autoantibody during this period. Unadjusted and adjusted hazard ratios (HRs) for the development of IA were estimated with survival analysis using a Weibull distribution.

RESULTS: Maternal intake of vitamin D via food was significantly associated with a decreased risk of IA appearance in offspring, independent of HLA genotype, family history of type 1 diabetes, presence of gestational diabetes mellitus, and ethnicity (adjusted HR = 0.37; 95% CI 0.17-0.78). Vitamin D intake via supplements, omega-3 fatty acids, and omega-6 fatty acids intake during pregnancy were not associated with appearance of IA in offspring.

CONCLUSIONS: Our findings suggest that maternal intake of vitamin D through food during pregnancy may have a protective effect on the appearance of IA in offspring.