Background Studies suggest that vitamin D deficiency is a risk factor for cardiovascular disease and diabetes. Vitamin D deficiency is prevalent in HIV patients but the effect of vitamin D supplementation on cardiovascular risk in this population is unknown. Methods We conducted a randomized, double-blind, placebo-controlled trial among 45 HIV-infected adults in Cleveland (OH, USA) on stable antiretroviral therapy with durable virological suppression and a baseline serum 25-hydroxyvitamin D level of ≤20 ng/ml. Participants were randomized 2:1 to vitamin D3 4,000 IU daily or placebo for 12 weeks. The primary outcome was a change in flow-mediated brachial artery dilation (FMD). Results Baseline demographics were similar except for age (vitamin D versus placebo, mean ±SD 47 ±8 versus 40 ±10 years; P=0.009). Both groups had reduced FMD at baseline (median values 2.9% [IQR 1.6–4.8] for vitamin D versus 2.5% [IQR 1.7–6.4] for placebo; P=0.819). Despite an increase in the concentration of serum 25-hydroxyvitamin D from baseline to 12 weeks (5.0 ng/ml [IQR −0.9–7.4] versus −1.9 ng/ml [IQR −4.0–0.1] for vitamin D versus placebo, respectively; P=0.003), there was no difference in FMD change (0.55% [IQR −1.05–2.13] versus 0.29% [IQR −1.61–1.77]; P=0.748). Vitamin D supplementation was associated with a decrease in total and non-high-density lipoprotein cholesterol, and an increase in indices of insulin resistance. Conclusions Among HIV-infected individuals with vitamin D deficiency, supplementation with 4,000 IU vitamin D3 daily for 12 weeks modestly improved vitamin D status and cholesterol but worsened insulin resistance without change in endothelial function. The mechanisms of resistance to standard doses of vitamin D and the complex role of vitamin D in glucose metabolism in this population require further investigation.

Background: Vitamin D insufficiency is common in cystic fibrosis (CF) and vitamin D repletion may have an important role in improving clinical outcomes in CF. This randomized, placebo-controlled, pilot study examined the feasibility and impact of a single, large dose of cholecalciferol on vitamin D status and clinical outcomes in subjects with CF. Methods: Thirty adults with were randomized in a double-blinded, pilot study to receive 250,000 IU cholecalciferol or placebo within 48 h of hospital admission for a pulmonary exacerbation. Concentrations of 25-hydroxyvitamin D (25(OH)D), clinical outcomes and potential adverse events were assessed up to one year after randomization. Mixed effects linear regression models were used to evaluate the difference in mean serum concentrations and log-rank analyses were used to evaluate survival. Results: Data from all subjects was analyzed. Serum 25(OH)D concentrations increased from a mean of 30.6 ± 3.2 ng/mL to 58.1 ± 3.5 ng/mL (p < 0.001) at one week and 36.7 ± 2.6 ng/mL by 12 weeks (p = 0.06) in the vitamin D group; in contrast, serum 25(OH)D concentrations remained unchanged in the placebo group. Unadjusted, one-year survival and hospital-free days were increased in the vitamin D group (p = 0.029, p = 0.036; respectively). There was also a trend toward increased IV antibiotic therapy-free days in the vitamin D group (p = 0.073). There were no signs of hypervitaminosis D or adverse events. Serum PTH and calcium concentrations were similar across both groups. Conclusions: In this pilot study, a single, oral bolus of cholecalciferol increased serum 25(OH)D concentrations and was associated with a trend toward improved clinical outcomes in CF subjects hospitalized for a pulmonary exacerbation. Further investigation is needed into the clinical impact of improved vitamin D status in patients with CF.

Vitamin D deficiency is common in tuberculosis (TB) and this may modulate immune responses. Objective To determine vitamin D status in patients with TB and examine sources of vitamin D in Tbilisi, Georgia. Research Methods and Procedures We measured plasma 25-hydroxyvitamin D (25(OH)D) and dietary vitamin D intake in pulmonary TB patients (n=85) in Tbilisi, Georgia. To determine the impact of season on vitamin D status, we tested in vitro conversion of 7-dehydrocholesterol (7-DHC) to previtamin D3 after sunlight exposure. Results In TB subjects, mean plasma 25(OH)D concentrations were 14.5 ± 7.0 ng/mL, and vitamin D insufficiency (25(OH)D < 30 ng/mL) occurred in 97% of subjects. Dietary sources of vitamin D were mainly fish, eggs, and butter. Daily intake was well below recommended daily intakes in TB subjects (172 IU + 196 IU). The conversion of 7-DHC to previtamin D3 was undetectable between October to March, and highest in June and July between 11:00 and 14:00 h. Conclusion Insufficient vitamin D dietary intake and limited production of vitamin D from sunlight during the majority of the year, may explain the high prevalence of vitamin D insufficiency TB patients in Tbilisi.

Background Vitamin D deficiency is common in HIV-infected individuals. In adults, traditional and HIV-related factors play a role in vitamin D status, and deficiency appears to impair immune restoration and exacerbate HIV complications, like cardiovascular disease (CVD). This study sought to determine factors contributing to vitamin D status in HIV-infected youth and investigate the relationship with CVD risk, inflammation, and immune restoration. Methods HIV-infected subjects (1–25 years old) were enrolled prospectively along with healthy controls that were group-matched by age, sex, and race. HIV data were collected for the HIV-infected group, while traditional risk factors, including vitamin D intake, sun exposure, skin pigmentation, physical activity level, and body mass index (BMI) were collected for both groups. Fasting lipids, plasma 25-hydroxyvitamin D (25(OH)D), and inflammation markers were measured. Results 200 HIV-infected subjects and 50 controls were enrolled. HIV group had 53% male, 95% black, and a mean age of 17.2±4.6 years. There was no difference in 25(OH)D between groups; 77% of HIV+ and 74% of controls had 25(OH)D <20 ng/mL. Only Fitzpatrick skin type was independently associated with 25(OH)D. No HIV variables were associated with 25(OH)D, even when HIV sub-populations were examined. Inflammation, CVD risk factors, and immune restoration were not independently associated with 25(OH)D. Conclusions Vitamin D deficiency is common among HIV-infected youth. However, HIV factors, CVD risk, inflammation, and immune restoration do not appear to have the same relationship with vitamin D as has been shown in adults. Supplementation trials are needed to determine if increasing 25(OH)D concentrations could better elucidate these relationships.