SERUM 25-HYDROXYVITAMIN D AND INCIDENCE OF DIABETES IN ELDERLY PEOPLE: THE PRO.V.A STUDY.

Context: increasing research has shown that low levels of serum 25-hydroxyvitamin (25OHD) predict the onset of diabetes, but no research is available on this issue in elderly people. Objective: to examine whether low serum levels of 25OHD are associated with a higher risk of incident type 2 diabetes over a lengthy follow-up in a representative group of elderly people. Design: a population-based cohort study as part of the Progetto Veneto Anziani (Pro.V.A) over a follow-up of 4.4 years Setting: general community. Participants: 2227 participants (1728 with follow-up visits and 499 died during the follow-up) over 65 years of age without diabetes at the baseline, among 2352 initially included. Main outcome measure: incident diabetes. Results: there were no baseline differences in known factors for the onset of diabetes (BMI, waist circumference, total cholesterol, renal function and HbA1c levels) between the groups with different serum 25OHD levels (≤ 25, 25-50, 50-75 and ≥ 75 nmol/L). Over a 4.4-year follow-up, 291 individuals developed diabetes, with an incidence of 28 events per 1000 person-years. No significant difference in the incidence of diabetes emerged between the baseline 25OHD groups. Cox's regression analysis, adjusted for potential confounders, revealed no relationship between low vitamin D levels and incident diabetes during the follow-up (HR: 1.05, 95 CI: 0.76-1.45, p=0.77; 1.44, 0.95-1.98, p=0.12 and 1.37, 0.87-2.16, p=0.17 for those with 25OHD ≤ 25, 25-50, and 50-75, respectively) Conclusion: baseline serum concentrations of 25OHD were unassociated with the incidence of diabetes in community-dwelling elderly people over a follow-up of 4.4 years.