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

Abstract

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(-1). 1788 patients were included; 87% were male, 76% Caucasian and 72% on antiretroviral therapy. The proportion with 25(OH)D < 50 nmol L(-1) was 27%, and <75 nmol L(-1) was 54%. Living in Melbourne compared with 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 with 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(-1). In those with biochemistry available (n = 1117), antiretroviral therapy was associated with 25(OH)D < 75 nmol L(-1); 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(-1). Cholesterol, the product of an alternative steroid pathway with a common precursor steroid, modified the effect of antiretroviral therapy on serum 25(OH)D.

Impact of Geographic Location on Vitamin D Status and Bone Mineral Density

“…Notably, latitude has been reported to be a strong determinant of the relative contribution of different behavioral factors analyzed by a multiple regression model [ 18 ]. In addition, a recent study [ 19 ] indicated that location was one of the strongest factors associated with serum 25(OH)D concentrations <75 nmol/L in subjects with human immunodeficiency virus. These findings emphasize that geographic location can be an important factor for vitamin D status in a population with vitamin D insufficiency.…”

Vitamin D and bone loss in HIV

“…Eckard et al recently presented a randomized, active-control, double-blind trial investigating two different monthly vitamin D 3 doses [60,000 or 120,000 IU/month] vs a control arm of 18,000 IU/month in HIV-infected youth on ART with baseline 25(OH)D ≤ 30 ng/mL. After 12 months of supplementation, 25(OH)D increased from 17 (11, 21) ng/mL to 31 (22, 37) ng/mL in the control group and from 18 (14, 22) ng/mL to 42 (33, 53) ng/mL in the combined medium and high dose groups (within and between groups p<0.001), but there were no differences between groups in changes in BMD or bone markers(80**). Notably, supplementation decreased markers of T-cell activation and exhaustion and monocyte activation regardless of the dose; although, participants given the highest dose showed the greatest improvements(81).…”

Association between serum 25-hidroxyvitamin D concentrations and ultraviolet index in Portuguese older adults: a cross-sectional study

“…Additionally, the UVI can be an indicator of potential for cutaneous synthesis of vitamin D: the higher the UVI the greater the potential [ 15 ]. In most studies, sun exposure and UVI are associated with 25(OH)D concentrations [ 16 – 19 ], but investigation in vivo is still complex. Several studies have also focused on the effect of latitude and season on 25(OH)D. UVI provides more information than latitude by itself, because it’s dependent on solar zenith angle and accounts for other variables that affect UV radiation available for synthesis.…”

“…In other countries in similar latitudes, such as Spain [ 21 – 23 ] and Italy [ 24 , 25 ] as well as in Europe, America and Australia more studies have been published in this area [ 26 , 27 ]. The investigation of the association between UVI and 25(OH)D was not done in older adults specifically [ 17 – 19 , 28 ].…”