Male circumcision and sexual risk behaviorsmay contribute to considerable ethnic disparities in HIV prevalence in Kenya: an ecological analysis

Background: HIV prevalence varies between 0.8 and 20.2 % in Kenya’s various ethnic groups. The reasons underlying these variations have not been evaluated before. Methods: We used data from seven national surveys spanning the period 1989 to 2008 to compare the prevalence of a range of risk factors in Kenya’s ethnic groups. Spearman’s and linear regression were used to assess the relationship between HIV prevalence and each variable by ethnic group. Results: The ethnic groups exhibited significant differences in a number of HIV related risk factors. Although the highest HIV prevalence group (the Luo) had the highest rates of HIV testing (Men 2008 survey: 56.8%, 95 % CI 51.0–62.5%) and condom usage at last sex (Men 2008:28.6%, 95 % CI 19.6–37.6%), they had the lowest prevalence of circumcision (20.9%, 95 % CI 15.9– 26.0) the highest prevalence of sex with a non-married, non-cohabiting partner (Men: 40.2%, 95 % CI 33.2–47.1%) and pre-marital sex (Men 2008:73.9%, 95 % CI 67.5–80.3%) and the youngest mean age of debut for women (1989 Survey: 15.7 years old, 95 % CI 15.2–16.2). At a provincial level there was an association between the prevalence of HIV and male concurrency (Spearman’s rho = 0.79, P = 0.04). Ethnic groups with higher HIV prevalence were more likely to report condom use (Me