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.