Supplementary Material for: Vitamin D Status, Gender Differences, and Cardiometabolic Health Disparities

Background: Vitamin D deficiency is an unrecognized
epidemic found in India and also worldwide. Despite the high prevalence
of diabetes among Indians, there is a paucity of data showing the
relationship between vitamin D status and cardiometabolic disparities.
In this study, we have examined the relationship between vitamin D and
cardiometabolic traits in a population from India. Methods: Circulating 25(OH)D levels were measured in 3,879 participants from the Asian Indian Diabetic Heart Study using ELISA kits. Results: Vitamin D levels were significantly reduced (p < 0.0001) in both men and women with obesity. However, compared to women, serum vitamin D was consistently lower in men (p
< 0.02), irrespective of the presence of obesity and type 2
diabetes. Multivariate regression revealed strong interaction of vitamin
D with body mass index that resulted in increased fasting glucose (p = 0.001) and reduced homeostasis model assessment of β-cell function (HOMA-B; p
= 0.01) in normoglycemic individuals. However, in gender-stratified
analysis, this association was restricted to men for both fasting
glucose (p = 2.4 × 10-4) and HOMA-B (p = 0.001). Conclusions:
Our findings suggest that vitamin D deficiency may significantly
enhance the risk of cardiometabolic disease among Asian Indians. Future
randomized trials and genetic studies are expected to clarify the
underlying mechanisms for gender differences in vitamin D deficiency,
and whether vitamin D-driven improvement in testosterone may contribute
to beneficial cardiometabolic outcomes in men.