Vitamin D status and HDL functionality in healthy pre-menopausal women.

Background: Low vitamin D (vitD) status has been linked to increased cardiovascular (CV) risk. Serum HDL cholesterol efflux capacity (CEC) is a metric of HDL functionality that is inversely correlated to CV risk. At present there is no data on the possible correlation between HDL CEC and vitD levels. Aim: We evaluated whether impaired HDL functionality occurs in otherwise healthy vitD deficient pre-menopausal women. Methods: 17 pre-menopausal vitD-deficient women and 14 age-matched women with normal vitD plasma levels were recruited. Serum HDL was isolated by precipitation with polyethylene glycole. HDL CEC was assessed by radioisotopic technique using specific cell models allowing to evaluate different cholesterol efflux pathways. Flow-mediated dilatation (FMD) and pulse wave velocity (PWV) were measured by standard techniques as markers of subclinical atherosclerosis. Results: No differences were found between groups lipid profile, including HDL levels. ABCG1-mediated CEC was lower in the vitD deficient group (by 20%, p<0.05), in whom FMD was also significantly lower (p<0.001). Meanwhile, aqueous diffusion- and ABCA1- mediated CEC did not differ between the two groups. PWV showed a non- statistical tendency to be higher in vitamin D- deficient women. Conclusions: These preliminary data on a small number of subjects suggest a specific impairment in ABCG1-mediated HDL CEC in vitD deficient pre-menopausal women, despite no differences in HDL serum levels. This observation encourages to study the possible role of vitD deficiency in HDL functional impairment and verify the relative weight of the two metabolic defects for CV risk in larger cohorts.