MALE CIRCUMCISION AND SUSCEPTIBILITY TO HIV-INFECTION AMONG MEN IN TANZANIA (VOL 11, PG 73, 1997)

Background: Evidence from ecological studies and from studies of and s exually transmitted disease (STD) patients in sub-Saharan Africa sugge sts that there is a protective effect of male circumcision against HIV infection. There are, however, few population-based studies that have controlled adequately for potential confounding factors. Methods: Dat a from five population-based studies in north-western Tanzania were us ed to investigate the association between male circumcision and the ri sk of HIV infection and STD. The effects of circumcision on HIV preval ence, syphilis (positive Treponema pallidum haemagglutination; TPHA) a nd self-reported STD were analysed, controlling for a range of demogra phic and sociocultural variables, and indicators of sexual behaviour. Results: In north-western Tanzania, circumcision was previously restri cted to Muslims and specific ethnic groups, but is now more widespread , particularly in urban areas and among more educated men. Assessment of the reliability and validity of self-reported circumcision status s howed that these data could be considered fairly accurate, although th ere was some tendency for circumcision to be over-reported. On univari ate analysis, circumcision status was unrelated to HIV prevalence in m ost studies. After controlling for confounding variables, however, the re was a modest but significant reduction of the HIV prevalence among circumcised men [odds ratio (OR), 0.62; 95% confidence interval (CI), 0.48-0.81]. This effect appeared stronger in urban areas (OR, 0.46; 95 % CI, 0.32-0.68) and roadside villages (OR, 0.65; 95% CI, 0.42-1.01) t han in rural areas and islands (OR, 1.00 and 1.01 respectively). There was no association between circumcision status and syphilis serology (TPHA), but there was a positive association between circumcision and self-reported STD, although this was not significant after adjustment for confounding variables. Conclusion: Male circumcision has a protect ive effect against HIV infection in this population, which may be stro nger in urban areas and roadside settlements than in the rural areas. Ethnic group and religious denomination are no longer the sole determi nants of male circumcision.