Abstract
BACKGROUND: There is growing evidence of an association between low vitamin D and HIV disease progression; however, no prospective studies have been conducted among adults receiving antiretroviral therapy (ART) in sub-Saharan Africa. METHODS: Serum 25-hydroxyvitamin D (25(OH)D) levels were assessed at ART initiation for a randomly selected cohort of HIV-infected adults enrolled in a trial of multivitamins (not including vitamin D) in Tanzania during 2006-2010. Participants were prospectively followed at monthly clinic visits for a median of 20.6 months. CD4 T-cell measurements were obtained every 4 months. Proportional hazard models were utilized for mortality analyses while generalized estimating equations were used for CD4 T-cell counts. RESULTS: Serum 25(OH)D was measured in 1103 adults 9.2% were classified as vitamin D deficient (<20 ng/ml), 43.6% insufficient (20-30 ng/mL), and 47.2% as sufficient (>30 ng/mL). After multivariate adjustment, vitamin D deficiency was significantly associated with increased mortality as compared to vitamin D sufficiency (HR: 2.00; 95% CI: 1.19-3.37; p = 0.009), whereas no significant association was found for vitamin D insufficiency (HR: 1.24; 95% CI: 0.87-1.78; p = 0.24). No effect modification by ART regimen or change in the associations over time was detected. Vitamin D status was not associated with change in CD4 T-cell count after ART initiation. CONCLUSIONS: Deficient vitamin D levels may lead to increased mortality in individuals receiving ART and this relationship does not appear to be due to impaired CD4 T-cell reconstitution. Randomized controlled trials are needed to determine the safety and efficacy of vitamin D supplementation for individuals receiving ART.