Plasma 25-Hydroxyvitamin D Concentration and Risk of Incident Type 2 Diabetes in Women

OBJECTIVE

To determine the association between 25-hydroxyvitamin D (25-OHD) concentration and risk of incident type 2 diabetes.

RESEARCH DESIGN AND METHODS

In a nested case-control study conducted among 608 women with newly diagnosed type 2 diabetes and 559 control subjects in the Nurses'' Health Study, we measured the association between baseline plasma 25-OHD concentration and risk of incident diabetes.

RESULTS

After adjusting for matching factors and diabetes risk factors, including BMI, higher levels of plasma 25-OHD were associated with a lower risk for type 2 diabetes. The odds ratio for incident type 2 diabetes in the top (median 25-OHD, 33.4 ng/ml) versus the bottom (median 25-OHD, 14.4 ng/ml) quartile was 0.52 (95% CI 0.33–0.83). The associations were consistent across subgroups of baseline BMI, age, and calcium intake.

CONCLUSIONS

Plasma 25-OHD concentration was associated with lower risk of incident type 2 diabetes in women.Growing evidence indicates that suboptimal vitamin D status may play a role in the development of type 2 diabetes (1). Results from longitudinal observational studies support the hypothesis that low vitamin D status is associated with development of type 2 diabetes; however, only one study has examined the association between blood 25-hydroxyvitamin D (25-OHD) concentration and incident type 2 diabetes, and there was no significant association among women (2,3). We examined prospectively the association between plasma 25-OHD concentration and risk of incident type 2 diabetes among women in a case-control study nested within the Nurses'' Health Study (NHS).