The researchers’ cross-sectional study used respondent-driving sampling conducted in Lagos, Kano, and Cross River states between July and September 2007. The participants were 879 MSM, 293 from each state, with a median age of 22 years. No syphilis infections were found. HIV infection was diagnosed among the MSM as follows: in Cross River, eight men (1.1 percent, confidence interval 0.1 percent to 2.2 percent); in Kano, 27 men (9.3 percent, CI 5.7 percent to 15.4 percent); in Lagos, 74 men (17.4 percent, CI 12.3 percent to 23.2 percent).
The MSM reported an average of 4.2 male anal sex partners in the previous six months. Selling sex to other men was reported by 24.4 percent of participants in Lagos and 36 percent in Kano. Sex with a girlfriend was reported by 49.7 percent of the MSM, and at least 6.5 percent reported paying female sex workers for sex.
Reports of consistent condom use during commercial sex with other men in the past six months ranged from 28 percent in Cross River to 34.4 percent in Kano. Reports of consistent condom use during non-commercial sex ranged from 23.9 percent in Kano to 45.8 percent in Lagos.
"Associations with HIV positivity included age in the three states, having been the receptive partner in anal sex in the past six months in Lagos, and in Lagos and Kano feeling at risk of HIV," the authors found. "Large differentials in HIV prevalence between states, together with high mobility, inconsistent condom use, and behavioral links with female sex partners, have the potential for further HIV transmission within MSM networks, and between MSM and the general population."