Cumulative exposure to stimulants and immune function outcomes among HIV-positive and HIV-negative men in the Multicenter AIDS Cohort Study

We examined associations between stimulant use (methamphetamine and cocaine) and other substances (nicotine, marijuana, alcohol and inhaled nitrites) with immune function biomarkers among HIV-seropositive (HIV {thorn}) men taking highly active antiretroviral therapy (ART) and HIV-seronegative (HIV2) men in the Multicenter AIDS Cohort Study. Among HIV {thorn} men, cumulative adherence to ART (4.07, 95% confidence interval [CI]: 3.52, 4.71, per 10 years of adherent ART use), and recent cohort enrolment (1.38; 95% CI: 1.24, 1.55) were multiplicatively associated with increase in CD4+/CD8+ ratios. Cumulative use of methamphetamine (0.93; 95% CI: 0.88, 0.98, per 10 use-years), cocaine (0.93; 95% CI: 0.89, 0.96, per 10 use-years) and cumulative medical visits (0.99; 95% CI: 0.98, 0.99, per 10 visit-years), each showed small negative associations with CD4+/CD8+ ratios. Among HIV2 men, cumulative medical visits (0.996; 95% CI: 0.993, 0.999), cumulative number of male sexual partners (0.999; 95% CI: 0.998, 0.9998, per 10 partner-years) and cigarette pack-years (1.10; 95% CI: 1.02, 1.18, per 10 pack-years) were associated with CD4+/CD8+ ratios over the same period. ART adherence is associated with a positive immune function independent of stimulant use, underscoring the influence of ART on immune health for HIV{thorn} men who engage in stimulant use.