INCIDENT HIV-1 INFECTION IN A COHORT OF YOUNG-WOMEN IN BUTARE, RWANDA

Objective: To determine the incidence of HIV-1 infection and associate d risk factors among young, seronegative, and sexually active women in a mixed rural and urban population in southern Rwanda. Design: A pros pective cohort study. Methods: Between October 1991 and April 1993, we completed a 2-year follow-up survey among HIV-1-seronegative women ag ed less than or equal to 30 years at the time of their initial HIV-1 s creening during pregnancy. All women aged less than or equal to 25 yea rs and a randomly selected sample of 26-30-year olds were invited to p articipate from five prenatal clinics in the Butare region. The interv iew focused on potential risk factors for HIV-1 acquisition during the 2-year interval between blood collection. Results: Out of 1524 women selected, 1150 (75%) participated in the follow-up survey. The 2-year incidence of HIV-1 infection was 2.7% [95% confidence interval (CI), 1 .8-3.9]. Teenage women were at the highest risk (incidence, 10.5%; 95% CI, 5.2-19.4), with incidence leveling off with increasing age (P<0.0 01). Women who began sexual activity recently were also at higher risk ; the lowest risk category consisted of women aged 26-30 years with 5 or more years of sexual experience. The more urban the geographic resi dence of the woman, the more likely she was to have acquired HIV-1 inf ection (P<0.001). In the urban and peri-urban zones, the poorest women were at significantly higher risk of incident HIV-1 infection than wo men reporting higher household income. In a multivariate analysis, you ng maternal age, marital status (being single, divorced or widowed), m ultiple sexual partners, and a history of sexually transmitted disease s remained strongly associated with incident HIV-1 infection. Geograph ic residence, hormonal contraception, and receipt of injections were n o longer significantly associated with incident HIV-1 infection when t hese other factors were accounted for simultaneously. Conclusion: Amon g young Rwandan women, the early years of sexual activity are particul arly dangerous for acquisition of HIV-1 infection. Interventions shoul d focus on young teenagers before they become sexually active.