Interventions needed in Cambodia to reduce HIV transmission from wealthier urban men to their wives

A household survey in Cambodia found an HIV prevalence of 0.6%, and also found that infection was more common in urban areas and in wealthier households, researchers report in the July 17^th edition of AIDS. A number of the findings support the hypothesis that the majority of infections in men are related to buying sex and that most women are infected by their husbands.

Previous monitoring of the HIV epidemic in Cambodia relied on surveys in specific groups, and suggested that prevalence was as high as 24% in injecting drug users, 21% in brothel-based sex workers, 5% in men who have sex with men, 2.5% in policemen, and 2.2% in pregnant women. These surveys did suggest that prevalence had been declining since 1998, but given weaknesses in the methodology, there was an urgent need to validate the estimates of the prevalence in the general population with a different approach.

The Cambodia Demography and Health Survey recruited a national representative sample of people aged 15 to 49 years from all parts of the country. Face-to-face interviews were conducted with 6514 men and 8188 women. (More women than men were interviewed in order to collect more reliable data on other topics such as fertility and infant mortality.)

Interviewees also gave fingerprick blood samples for HIV antibody testing. They did not receive their test results, but were given information about free local HIV testing services.

HIV prevalence in the general population was lower than expected, at 0.6% for both men and women. However it was considerably higher in urban areas than in rural areas: 1.6% in urban men, but 0.4% in rural men, with similar figures for women. (Approximately 15% of the Cambodian population lives in urban areas.)

HIV infection was largely limited to people who were married or had previously been married. Even adjusting for age, the highest rates were in people who were divorced, separated or widowed (women in this group were 23 times more likely to be HIV-positive than single women). Moreover, because women tended to marry younger than men, infection was more common in women under the age of 29 than in men of the same age group.

Thirty per cent of women were at least five years younger than their spouses, and HIV prevalence depended on the age gap. Women who were at least ten years younger than their spouse were five times as likely to have HIV as women whose spouse was the same age.

While 0.3% of sexually active women reported having more than one partner in the past year, 17% of urban men and 8% of rural men did so. Around two-thirds of these men’s partners were sex workers. Men with multiple partners were four times as likely to have HIV as men who only had one partner.

Both men and women who scored high on a wealth index were more likely to have HIV than poorer people, with the relationship being strongest for men. Moreover, in urban areas, men with some education had higher HIV prevalence than those with no schooling, but the opposite relationship was seen for women.

The authors note that some other studies have identified links between HIV and wealth, rather than poverty. However they argue that the relationship can differ by sex. In Cambodia, the HIV epidemic is largely driven by sex work and male clients, and the survey confirmed that paid and extramarital sex are more common in men with higher socio-economic status. However, HIV in wealthier women is likely to be linked to the behaviour of husbands rather than women themselves.

Nonetheless, the authors do also suggest that educated women may have greater independence, economic power and ability to negotiate with their partners.

For at least ten years, prevention activities in Cambodia have intensively targeted sex workers and their clients with a focus on 100% condom use and treatment of sexually transmitted infections. The authors believe these programmes should be sustained, but call for additional interventions to reduce HIV transmission from husbands to wives. “Efforts to empower women for better access to information, education and care seem critically important,” they suggest.