Risk factors for active syphilis and TPHA seroconversion in a rural African population

Objectives: Syphilis is an important cause of morbidity in sub-Saharan Afri ca, and a cofactor for the sexual transmission of HIV. A better understandi ng of the prevalence and risk factors of syphilis in African populations wo uld help to formulate effective interventions for its prevention and treatm ent. Methods: The prevalence and incidence of syphilis were obtained from a coho rt recruited in Mwanza, Tanzania. Two unmatched case-control studies nested within the cohort provide information on potential risk factors. Results: The prevalence of active syphilis (TPHA positive and RPR positive any titre) was 7.5% in men and 9.1% in women, but in youths (aged 15-19 yea rs) the prevalence was higher in women (6.6%) than in men (2.0%). The incid ence of TPHA seroconversion was highest in women aged 15-19 at 3.4% per yea r, and around 2% per year at all ages among men. A higher prevalence of syp hilis was found in those currently divorced or widowed (men: OR=1.61, women : OR=2.78), and those previously divorced or widowed (men: OR=1.51, women: OR=1.85). Among men, prevalence was associated with lack of circumcision (O R=1.89), traditional religion (OR=1.55), and reporting five or more partner s during the past year (OR=1.81) while incidence was associated with no pri mary education (OR=2.17), farming (OR=3.85), and a self perceived high risk of STD (OR=3.56). In women, prevalence was associated with no primary educ ation (OR=2.13), early sexual debut (OR=1.59), and a self perceived high ri sk of STD (OR=3.57), while incidence was associated with living away from t he community (OR=2.72). Conclusion: The prevalence and incidence of syphilis remain high in this ru ral African population. More effort is needed to promote safer sexual behav iour, and to provide effective, accessible treatment. The high incidence of syphilis in young women calls for sexual health interventions targeted at adolescents.