Stroke risk factors in an incident population in urban and rural Tanzania: a prospective, community-based, case-control study

Background The burden of stroke on health systems in low-income and middle-income countries is increasing. However, high-quality data for modifi able stroke risk factors in sub-Saharan Africa are scarce, with no communitybased, case-control studies previously published. We aimed to identify risk factors for stroke in an incident population from rural and urban Tanzania. Methods Stroke cases from urban Dar-es-Salaam and the rural Hai district were recruited in a wider study of stroke incidence between June 15, 2003, and June 15, 2006. We included cases with fi rst-ever and recurrent stroke. Community-acquired controls recruited from the background census populations of the two study regions were matched with cases for age and sex and were interviewed and assessed. Data relating to medical and social history were recorded and blood samples taken. Findings We included 200 stroke cases (69 from Dar-es-Salaam and 131 from Hai) and 398 controls (138 from Dar-es- Salaam and 260 from Hai). Risk factors were similar at both sites, with previous cardiac event (odds ratio [OR] 7·39, 95% CI 2·42–22·53; p<0·0001), HIV infection (5·61, 2·41–13·09; p<0·0001), a high ratio of total cholesterol to HDL cholesterol (4·54, 2·49–8·28; p