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, gamma-glutamyltransferase (GGT), uric acid, and hemoglobin A(1c) (HbA(1c)). 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 HbA(1c) (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 HbA(1c) (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.