Background: Regional and geographical variations exist in stroke burden and risk factor distribution. The unique and dominant risk factors for stroke among people of African ancestry where the burden of stroke is escalating, are poorly understood. Such information is crucial in prioritizing tailor-made interventions to tackle the menace of stroke in developing countries.
Purpose: We aimed to identify and quantify the contributions of the topmost modifiable risk factors for stroke occurrence in people of African ancestry within the context of the Stroke Investigative Research and Educational Network (SIREN), the largest study of stroke in Africa.
Methods: The SIREN study is an ongoing, multicenter, case-control study involving several sites in Nigeria and Ghana. Cases included adults aged >18 years with first clinical stroke within 8 days of current symptom onset with CT scan confirmation. Controls were stroke-free adults, mostly from the communities in the catchment areas of the SIREN hospitals where cases were recruited. A systematic evaluation of traditional vascular risk factors as well as lifestyle and behavioral factors were assessed for cases and controls.
Results: 1,638 cases and 1,653 controls with mean ages of 58.52 and 57.76 years respectively were recruited. Ischemic and hemorrhagic stroke types constituted 62.4% and 36.1% of stroke respectively. Among ischemic stroke subjects, 45.7%, 36.3%, 13.6%, 1.0% and 3.4% had small-vessel, large-artery atherosclerosis, cardio-embolic, others and unknown subtypes according to the TOAST classification. Leading vascular risk factors identified among stroke subjects compared with controls were hypertension- 79.3% vs 34.6%, p<0.001; Dyslipidemia 20.8% vs 6.6%, p<0.001; Diabetes mellitus- 24.4% vs 12.8% and history of cardiac diseases 15.4% vs 7.9%, p<0.001. Adjusted ORs (95% CI) for hypertension, dyslipidemia, cardiac disease and diabetes among stroke subjects compared with controls were 6.43 (5.84-7.54), 2.08 (1.61-2.69), 1.48 (1.15-1.91) and 1.29 (1.05-1.60) respectively.
Conclusion: Implementation of interventions towards mitigating the impact of vascular risk factors at the population level would be essential in curtailing the growing burden of stroke in Africans.