Sex with older men is not placing women under 30 at higher risk of HIV infection in rural South Africa, and relationships with older men may even be protecting women over 30 from infection, according to results from a eight-year study presented on Thursday at the 21st Conference on Retroviruses and Opportunistic Infections (CROI) in Boston.
Although cross-sectional studies of HIV prevalence have suggested that younger women are placed at high risk of HIV infection as a result of relationships with older men in sub-Saharan Africa, this is the first study to follow women over a long period and to look at HIV incidence and age of sexual partners.
Guy Harling of the Africa Centre for Health and Population Studies said that campaigns in many African countries that seek to discourage or even stigmatise age-different relationships may prove to be an inefficient use of resources, or may even prove counter-productive. In KwaZulu-Natal province, for example, billboard campaigns proclaim: “Older men + young girls = teenage pregnancy & AIDS. Sugar daddies destroy lives.”
The study was conducted in the Hlabisa district of KwaZulu-Natal, a rural area in the north of the province with amongst the highest levels of HIV infection in the world. Sexually active women aged 15 to 49 were recruited and tested annually for HIV between 2005 and 2012, as well as questioned about the age of their most recent sexual partner at each annual study visit.
The study enrolled 2444 initially HIV-negative women, accumulated 5913 person-years of follow-up, and observed an incidence of 7.75 infections per 100 person-years in women aged 15 to 29. On average, the sexual partners of women in the 15 to 29 age group were five years older, and there was no significant difference in the risk of HIV infection in this age group between women who reported sexual partners less than five years older, five to nine years older and ten or more years older.
In contrast, the risk of HIV infection fell among women aged 30 to 49 for each additional year of age difference between a woman and her partner. Women with a partner between five and ten years older had a 37% reduction in the risk of HIV infection compared with women whose partner was of a similar age, while women whose partner was ten or more years older had a 52% reduction in the risk of HIV infection.
Harling suggested that the reduced risk in older women may be a consequence of extensive social networks that allow older women to make a careful choice of partner. It is also possible that younger women may have fewer opportunities to encounter an older partner with HIV infection than in an urban area.
Harling G et al. Age-disparate relationships and HIV incidence amongst rural South Africa women. 21st Conference on Retroviruses and Opportunistic Infections, Boston, abstract 145, 2014.