UCLA

Background

Aging in males is associated with lower testosterone levels and a decrease in diurnal variation of testosterone secretion. Cross-sectional studies have shown lower than expected testosterone levels among HIV-infected men, but whether age-related changes in serum testosterone differ by HIV serostatus are not known.

Methods

HIV-infected men from the Multicenter AIDS Cohort Study (MACS), age ≥ 45 years at highly active antiretroviral therapy initiation, who had ≥ 2 samples from the subsequent 10 years, were matched to HIV-uninfected men by age, race, MACS site, and calendar time of samples. Linear mixed-effects regression models were used to determine whether free testosterone (FT) and its rate of change differed by HIV serostatus.

Results

One hundred eighty-two HIV-infected and 267 HIV-uninfected men were included, median age: 48.8 years (interquartile range: 45.8-53.4), median numbers of FT measurements per participant 4 (interquartile range: 3-5), 65% were drawn in the adjusted morning (AM). Mean-adjusted FT levels were lower among HIV-infected than HIV-uninfected men in AM samples {-6.1 ng/dL [95% confidence interval (CI): -9.8 to -2.4], P = 0.001}, but not in afternoon samples [-1.7 ng/dL (-6.0 to 2.6), P = 0.441]. The rate of FT decline with age did not differ by HIV serostatus: 9.2 ng/dL (95% CI: -13.4 to -5.0) per 10 years for HIV-infected vs. 7.9 ng/dL (95% CI: -10.2 to -5.5) for HIV-uninfected men, P = 0.578.

Conclusions

FT decreased similarly with increasing age regardless of HIV serostatus. The lower AM, but not adjusted afternoon, FT levels among HIV-infected men compared with HIV-uninfected men suggest a loss of diurnal variation in FT levels among HIV-infected men.