Age Differences in Sexual Partners and Risk of HIV-1 Infection in Rural Uganda

The current study is an observational analysis of the sexual behavior characteristics of adolescents in Rakai District, Uganda, to assess the degree to which age differences between sexual partners affect the risk of HIV infection. During a randomized community-based trial the researchers conducted in 56 communities of the rural Rakai District between 1994 and 1998, participants answered questionnaires on sociodemographic characteristics and behaviors and were tested for HIV and STDs. Twenty percent of 6,177 ever sexually active women ages 15 to 29 had HIV. Young women had a higher prevalence of HIV than men. HIV-1 prevalence increased with age from 7.6 percent in women ages 15 to 19, to 22.3 percent in 20- to 24-year-olds, to 32.1 percent in 25- to 29-year-olds. The mean age of first marriage was 19.3 years; median age at first sex was 15 for 15- to 19-year-olds, and 16 for 20- to 29-year-olds.

Investigators found higher rates of HIV in women in union than in those never married (18.1 percent and 14.7 percent respectively) and high rates of infection in separated, divorced or widowed women (45 percent). HIV risk associated with the age difference between partners was greatest among women ages 15 to 19 years with male partners 10 or more years older and women ages 20 to 24 years with partners 10 or more years older. The age difference in partners was not associated with HIV risk in women ages 25 to 29 years.

"Estimates ... suggest that 12.4 percent of the HIV prevalence in 15- to 19-year-olds and 5.1 percent of the prevalence in 20- to 24-year-olds can be attributed to relationships with men 10 or more years older, largely within marital relationships," the authors noted. "Among HIV-infected women 15 to 19 years of age, 88.5 percent were ever married compared with 66.4 percent of HIV-negative women aged 15 to 19 years. This suggests that many of the HIV-positive female adolescents were infected by an older husband."

The researchers suggest that HIV interventions in the area address economic and cultural factors that lead young women to marry older men with higher incomes, rather than adolescent boys who are not seen as potential husbands. They explain the apparent paradox of their findings -- that HIV incidence declined significantly with increasing differentials in partner age for women ages 25-29 -- by referring to the selection of the population.

"Because women with older male partners have higher HIV prevalence, there are selectively fewer HIV-negative women still at risk for incident HIV infections," they wrote. "Also, these women who previously avoided infection may be at lower risk (for biologic or behavioral reasons) and thus less likely to seroconvert during follow-up."

"In conclusion," the scientists summed up, "this study has shown the importance of age differences between partners as a risk factor for HIV acquisition in young women, particularly young married adolescents. The age differences between women and their male partners cannot fully account for the excess HIV infections in young women relative to young men in the Rakai population, however. ... Further research into the attitudes, behaviors, and physiologic characteristics of this group and their partners is warranted."

Back to other news for September 8, 2003

Search the Newsroom archive