Ultraviolet Index and Location are Important Determinants of Vitamin D Status in People with Human Immunodeficiency Virus

Karen M. Klassen, Christopher K. Fairley, Michael G. Kimlin, Mark Kelly, Tim R.H. Read, Jennifer Broom, Darren B. Russell, Peter R. Ebeling

This study aimed to document the vitamin D status of HIV-infected individuals across a wide latitude range in one country and to examine associated risk factors for low vitamin D. Using data from patients attending four HIV specialist clinics across a wide latitude range in Australia, we constructed logistic regression models to investigate risk factors associated with 25(OH)D<75 nmol/L. 1788 patients were included; 87% were male, 76% Caucasian and 72% on antiretroviral therapy. The proportion with 25(OH)D<50 nmol/L was 27%, and <75 nmol/L was 54%. Living in Melbourne compared to Cairns (adjusted odds ratio (aOR) 3.30; 95%CI 2.18, 4.99, p<0.001) and non-Caucasian origin (aOR 2.82, 95%CI 2.12, 3.75, p<0.001) was associated with an increased risk, while extreme UV index compared to low UV index was associated with a reduced risk (aOR 0.33; 95%CI 0.20, 0.55, p<0.001) of 25(OH)D <75 nmol/L. In those with biochemistry available (n=1117), antiretroviral therapy was associated with 25(OH)D <75 nmol/L, however, this association was modified by serum cholesterol status. Location and UV index were the strongest factors associated with 25(OH)D <75 nmol/L. Cholesterol, the product of an alternative steroid pathway with a common precursor steroid, modified the effect of antiretroviral therapy on serum 25(OH)D. This article is protected by copyright. All rights reserved.