Intake of a cohort study of urban factory workers in northwest Tanzania. Risk factors for HIV-1 infection.

A cohort study has been started of urban factory workers and their spouses in Tanzania in order to 1) identify risk factors for HIV-1 seroconversion and 2) document changes over time in risk behavior in particular condom use and partner change and determine whether these are associated with a reduced incidence of HIV-1 and other sexually transmitted diseases. The authors report findings at intake from October 1991 to March 1992. Study participants were interviewed examined and screened for HIV-1 and syphilis. HIV-1 prevalence was 91/296 (10%) in males and 36/217 (17%) in females. Statistically significant risk factors for HIV-1 infection in males were age group region of birth not being married for more than 5 years being uncircumcised having had a genital ulcer in the past four months and having received injections from medical staff in the past four months. HIV-1 incidence in this group is expected to be between 1% and 2% per year. It is concluded that a longitudinal study is needed to assess the importance of partner change. This cohort appears to be suitable for such a study as HIV-1 incidence is expected to be fairly high HIV-1 prevalence and risk factors are comparable to those of the general population and cooperation of the factory workers is good. (authors)