Vitamin D deficiency and non-lipid biomarkers of cardiovascular risk

INTRODUCTION Deficient 25-hydroxyvitamin D (25(OH)D) levels have been associated with dyslipidemia and cardiovascular diseases, though the underlying mechanism of these associations is uncertain. We analyzed associations between vitamin D and other non-lipid biomarkers of cardiovascular risk to better elucidate possible relationships between deficient 25(OH)D and cardiovascular disease. MATERIAL AND METHODS We performed a cross-sectional analysis of 4,591 adults included in a clinical laboratory database from 2009 to 2011 with available measurements for 25(OH)D and the following biomarkers: homocysteine (Hcy), high-sensitivity C-reactive protein (hs-CRP), cystatin-C, creatinine, γ-glutamyltransferase (GGT), uric acid, and hemoglobin A1c (HbA1c). We calculated odds ratios (OR) of having high levels of each biomarker associated with 25(OH)D deficiency (< 20 ng/ml) compared to optimal levels (≥ 30 ng/ml) using logistic regression adjusted for age, sex, and lipids. RESULTS The mean ± SD age was 60 ±14 years and 46% of patients were women. In multivariable-adjusted models, adults with deficient 25(OH)D compared to those with optimal levels had increased odds of elevated biomarkers as follows: Hcy (OR = 2.53, 95% CI: 1.92-3.34), hs-CRP (1.62, 1.36-1.93), cystatin-C (2.02, 1.52-2.68), creatinine (2.06, 1.35-3.14), GGT (1.39, 1.07-1.80), uric acid (1.60, 1.31-1.95), and HbA1c (2.47, 1.95-3.13). In analyses evaluating women and men separately, 25(OH)D deficient women but not men had increased odds of elevated levels of all biomarkers studied. There were significant interactions based on sex between 25(OH)D and Hcy (p = 0.003), creatinine (p = 0.004), uric acid (p = 0.040), and HbA1c (p = 0.037). CONCLUSIONS Deficient 25(OH)D is associated with elevated levels of many biomarkers of cardiovascular risk, particularly among women, in a United States population.