Vitamin d deficiency is associated with insulin resistance independent of intracellular calcium, dietary calcium and serum levels of parathormone, calcitriol and calcium in premenopausal women.

Abstract

There is evidence that vitamin D deficiency is associated with increased risk of cardiovascular disease. However, it is not known if this association is independent of dietary calcium, intracellular calcium and serum levels of parathormone, calcitriol and calcium. To investigate the independent relationship of vitamin D deficiency with insulin resistance, lipid profile, inflammatory status, blood pressure and endothelial function. Cross-sectional study conducted with 73 healthy Brazilian premenopausal women aged 18 - 50 years. All participants were evaluated for: 25 hydroxyvitamin D serum levels, anthropometric parameters, body composition, calcium metabolism, insulin resistance, lipoprotein profile, inflammatory status, blood pressure and endothelial function. Endothelial function was assessed by reactive hyperemia index using Endo-PAT 2000®. Women were stratified in two groups: with vitamin D deficiency (25 hydroxyvitamin D < 20 ng/ml; n=12) and without vitamin D deficiency (25 hydroxyvitamin D ≥ 20 ng/ml; n=61). Participants with vitamin D deficiency compared with those without deficiency of this vitamin had significantly higher levels of glucose (88.25 ± 3.24 vs. 80.15 ± 1.13 mg/dl), greater HOMA-IR (6.43 ± 0.73 vs. 4.42 ± 0.25) and lower reactive hyperemia index (1.68 ± 0.1 vs. 2.17 ± 0.1). After adjustments for confounding factors including age, body mass index, waist circumference, dietary calcium, intracellular calcium and serum levels of parathormone, calcitriol and calcium differences between groups remained significant, regarding glucose and HOMA-IR. The findings of the present study suggest that vitamin D deficiency is associated with insulin resistance independent of dietary calcium, intracellular calcium and serum levels of parathormone, calcitriol and calcium in healthy premenopausal women.