Longitudinal Changes in Sex Hormone–Binding Globulin in Men With HIV

Abstract

Background: Sex hormone–binding globulin (SHBG) is a glycoprotein that regulates sex hormone bioavailability and increases with age in the general population. SHBG concentrations are higher in people with HIV, a population in whom accelerated aging has been hypothesized. It is unclear whether longitudinal changes in SHBG increase over time and differ by HIV serostatus. Methods: In a longitudinal study, SHBG was measured in 182 men with HIV (MWH) and 267 men without HIV (seronegative) from the Multicenter AIDS Cohort Study and matched for age, race, site, and time, with ≥2 SHBG serum samples over the 10 years after HAART initiation. Multivariable linear mixed-effects regression models were used to evaluate whether log-transformed SHBG [ln(SHBG)] and its rate of change differed by HIV serostatus. Results: At baseline, the mean age in MWH was similar to that in HIV-seronegative men (51 ± 5 vs 49 ± 6 years). However, SHBG mean values were higher in MWH compared with those in HIV-seronegative men (65.6 ± 48.8 vs. 45.4 ± 22 nmol/L, P < 0.001). In a fully adjusted model, SHBG increased over time and at a faster rate in MWH compared with that in HIV-seronegative men: [2.0%/year (95% CI: 1.4 to 2.7) vs 1.3%/year (95% CI: 0.8 to 1.8), respectively, P = 0.038]. Among MWH, higher SHBG concentrations were significantly associated with lower CD4+ T-cell count [β= −0.02 (95% CI: −0.03 to −0.0002), P < 0.05], fewer cumulative years on zidovudine [β = −0.027 (95% CI: −0.045 to −0.009), P < 0.001], and greater cumulative years on nonnucleoside reverse transcriptase inhibitors drugs [β = 0.022 (95% CI: 0.0006 to 0.04), P < 0.05]. Conclusions: Aging-related increases in SHBG were faster in MWH compared with those in HIV-seronegative men and were related to poorer immunologic status and antiretroviral medication exposure. The mechanisms and consequences of these findings require further investigation.