Association between serum vitamin A and E levels and HIV-1 disease progression

Objective: To examine the associations between serum vitamin A and E levels and risk of progression to three key outcomes in HIV-1 infection: first AIDS diagnosis, CD4+ cell decline to < 200 cells x 10⁶/l, and mortality. Design: Non-concurrent prospective study. Methods: Serum levels of vitamins A and E were measured at the enrollment visit of 311 HIV-seroprevalent homo-/bisexual men participating in the Baltimore/Washington DC site of the Multicenter AIDS Cohort Study. Cox proportional hazards models were used to estimate the relative hazard of progression to each outcome over the subsequent 9 years, adjusting for several independent covariates. Results: Men in the highest quartile of serum vitamin E levels (≤ 23.5 μmol/l) showed a 34% decrease in risk of progression to AIDS compared with those in the lowest quartile [relative hazard (RH), 0.66; 95% confidence interval (CI), 0.41-1.06)]. This effect was statistically significant when comparing the highest quartile of serum vitamin E to the remainder of the cohort (RH, 0.67; 95% CI, 0.45-0.98). Associations between serum vitamin A levels and risk of progression to AIDS were less clear, but vitamin A levels were uniformly in the normal to high range (median = 2.44 μmol/l). Similar trends were observed for each vitamin with mortality as the outcome, but neither vitamin was associated with CD4+ cell decline to < 200 cells x 10⁶/l. Men who reported current use of multivitamin or single vitamin E supplements had significantly higher serum tocopherol levels than those who were not taking supplements (P = 0.0001). Serum retinol levels were unrelated to intake of multivitamin or single vitamin A supplements. Conclusions: These data suggest that high serum levels of vitamin E may be associated with slower HIV-1 disease progression, but no relationship was observed between retinol levels and disease progression in this vitamin A-replete population.