Vitamin D deficiency and replacement: Relationships to cardiovascular health

Abstract

Background. Cardiovascular disease is the most common cause of mortality and morbidity in the United States as well as many other nations. Recent evidence supports an association of vitamin D deficiency with hypertension, peripheral vascular disease, diabetes mellitus, metabolic syndrome, coronary artery disease, and heart failure. We wished to study the association of vitamin D deficiency in a cohort of patients followed by a large cardiovascular practice at an academic medical institution, as well as the association of vitamin D replacement with improvement in cardiovascular outcomes.

Methods. Serum vitamin D measurements for 5 years and 8 months (1/1/2004 to 10/8/2009) from The University of Kansas Hospital were obtained. These values were matched to patient demographic, physiologic and disease state variables from the cardiovascular database. Serum vitamin D levels were analyzed as a continuous variable and as normal (>30ng/ml) or deficient. Descriptive statistics, univariate analysis, multivariate analysis, survival analysis, and Cox proportional hazard modeling were performed.

Results. 10,899 patients were available for analysis. Mean age was 58.3 +/- 14.9 years. There were 7758 (71%) women and 3141 (29%) men. Mean weight was 185.7 +/-52.0 lbs and BMI was 29.9 +/- 7.7 Ejection fraction was 57.2 +/- 10.4%. Mean vitamin D was 24.1 +/- 13.6 ng/ml. 3294 (29.7%) subjects were in normal range (.30ng/ml) and 7665 (70.3%) were deficient (<30ng/ml). Vitamin D deficiency was found to be associated with several cardiovascular disease states including hypertension, coronary artery disease and cardiomyopathy; as well as diabetes and death (all P’s < .05). Logistic regression analysis found vitamin D deficiency to be a strong predictor of death (OR 2.64, CI 1.901-3.662, P < .0001). This association persisted with other clinical variables such as, BMI, gender, and ejection fraction added to the model and was confirmed by survival as well as hazard function analysis. Vitamin D replacement conferred substantial survival benefit (OR for death 0.39, CI 0.277-0.534, P < .0001) and was particularly beneficial in vitamin D deficient patients. The interaction of vitamin D deficiency and supplementation was analyzed as well as the association of vitamin D deficiency and certain coronary artery disease risk factors.

Conclusions. Vitamin D deficiency is a significant risk factor for several cardiovascular disease states and is a significant independent predictor of reduced survival. Vitamin D supplementation improves survival with greater benefit in deficient patients. Prospective randomized trials of vitamin D supplementation in patients with cardiovascular diseases are warranted, as well as consideration for increased supplementation in the general public.

Keywords: Vitamin D, Cardiovascular Diseases, Risk Factors