Risk Factors for Vitamin D Deficiency in HIV-Infected Patients in the South Central United States

Abstract

We evaluated the prevalence of serum 25-hydroxyvitamin D [25(OH)D] deficiency and the risk factors for vitamin D deficiency in HIV-infected patients in the South-Central United States. The study consisted of a cross-sectional assessment of vitamin D levels in HIV-infected patients receiving routine clinical care from a private practice in Houston, Texas (latitude 29°N). Vitamin D deficiency was defined as 25(OH)D less than 20 ng/ml (<50 nmol/liter). Two-hundred enrolled patients were surveyed with a vitamin D questionnaire to determine daily supplemental vitamin D intake, dietary vitamin D intake, and average sunlight exposure (minutes/day). Multivariate logistic regression analysis was used to determine significant risk factors for vitamin D deficiency. Median 25(OH)D was 15.5 ng/ml (interquartile range 10.9-24.6) for the total population (n=200). Approximately, two-thirds (64%) of patients had vitamin D deficiency and 20.5% had severe vitamin D deficiency [25(OH)D <10 ng/ml or <25 nmol/liter]. In univariate analysis, African-American race, current tobacco use, increased body mass index (BMI), lower serum calcium level, no supplemental vitamin D use, and low daily supplemental and total daily vitamin D intake were significantly associated with vitamin D deficiency. In multivariate analysis, African-American race [adjusted odds ratio (AOR) 3.53 (95% confidence interval (CI) 1.83-6.82)], higher BMI [AOR 1.07 (95% CI 1.002-1.139)], and low daily vitamin D supplemental intake [AOR 0.997 (95% CI 0.996-0.999)] were significantly associated with vitamin D deficiency. No HIV factors including antiretroviral class use were significantly associated with either vitamin D deficiency or severe vitamin D deficiency. Vitamin D deficiency and severe vitamin D deficiency were highly prevalent in this HIV population. In the HIV population, African-Americans or patients with a high BMI may benefit from vitamin D supplementation.