Risk factors for vitamin D deficiency and relationship with cardiac biomarkers, inflammation and immune restoration in HIV-infected youth

Abstract

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: In total, 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.

Figure 1

Mean 25-hydroxyvitamin D concentrations are shown by study group, unadjusted and adjusted for age, Fitzpatrick skin scale score, gender, season, sun exposure, physical activity, and body mass index. There were no significant differences between groups. Error bars represent standard deviation.

Figure 2

The percentages of subjects with different categories of 25(OH)D concentration are depicted by study group. The proportion of subjects with vitamin D deficiency (25(OH)D <20 ng/mL) was no different between groups (odds ratio 1.10, 95% confidence interval 0.39, 3.15, P=0.97). <10 ng/mL = severe vitamin D deficiency; 10–19.9 ng/mL = vitamin D deficiency; 20–29 ng/mL = vitamin D insufficiency; >29 ng/mL = optimal vitamin D. 25(OH)D), 25-hydroxyvitamin D.

Figure 3

Mean 25-hydroxyvitamin D (25(OH)D) concentrations are shown based on Fitzpatrick skin type for all subjects and separately for black subjects. This figure indicates that Fitzpatrick skin type is associated with 25(OH)D concentration for all races, although driven mainly by the black subjects. Fitzpatrick skin types 4 and 5 have the lowest concentrations of 25(OH)D, all of whom were black. The association between 25(OH)D and Fitzpatrick skin type remained significant for the whole cohort and when limited to black race (P<0.001), even after adjusting for age, race, sex, season, sun exposure, physical activity, body mass index, and study group. Error bars represent standard error. Fitzpatrick skin type 1: N=2 (0% black); type 2: N=6 (0% black); type 3: N=34 (92% black); type 4: N=85 (100% black); type 5: N=72 (100% black).