Behavioral, biological, and demographic risk and protective factors for new HIV infections among youth in Rakai, Uganda.

BACKGROUND Prevalence of HIV infection is considerable among youth, although data on risk factors for new (incident) infections are limited. We examined incidence of HIV infection and risk and protective factors among youth in rural Uganda, including the role of gender and social transitions. METHODS Participants were sexually experienced youth (15-24 years old) enrolled in the Rakai Community Cohort Study, 1999-2008 (n = 6741). Poisson regression with robust standard errors was used to estimate incident rate ratios (IRR) and 95% confidence intervals (CI) of incident HIV infection. RESULTS HIV incidence was greater among young women than young men (14.1 vs. 8.3 per 1000 person-years, respectively); this gender disparity was greater among teenagers (14.9 vs. 3.6). Beyond behavioral (multiple partners and concurrency) and biological factors (sexually transmitted infection symptoms), social transitions such as marriage and staying in school influenced HIV risk. In multivariate analyses among women, HIV incidence was associated with living in a trading village (adjusted IRR (aIRR) = 1.48; 95% CI: 1.04 to 2.11), being a student (aIRR = 0.22; 95% CI: 0.07 to 0.72), current marriage (aIRR = 0.55; 95% CI: 0.37 to 0.81), former marriage (aIRR = 1.73; 95% CI: 1.01 to 2.96), having multiple partners, and sexually transmitted infection symptoms. Among men, new infections were associated with former marriage (aIRR = 5.57; 95% CI: 2.51 to 12.36), genital ulceration (aIRR = 3.56; 95% CI: 1.97 to 6.41), and alcohol use (aIRR = 2.08; 95% CI: 1.15 to 3.77). CONCLUSIONS During the third decade of the HIV epidemic in Uganda, HIV incidence remains considerable among youth, with young women particularly at risk. The risk for new infections was strongly shaped by social transitions such as leaving school, entrance into marriage, and marital dissolution; the impact of marriage was different for young men than women.