The epidemiology of epilepsy in rural Tanzania :prevalence, phenotype, risk factors and treatment gap

Abstract

Introduction Epilepsy is especially prevalent in low- and middle-income countries, including those in sub-Saharan Africa (SSA). There are few case-controlled data on epilepsy from SSA, where epilepsy remains largely untreated and highly stigmatized. Aims To determine the prevalence of active epilepsy among adults in a rural population in northern Tanzania. To describe the pattern of disease and quantify the epilepsy treatment gap (ETG) in this population. Methods People with epilepsy (PWE) were identified through door-to-door screening of the adult study population (n=103,026) using a previously validated screening questionnaire. Controls were recruited from the background population. Odds ratios for risk factors and impacts of epilepsy were calculated using logistic regression. The burden of neurocysticercosis (NCC) was assessed using neuro-imaging in cases and serology. The ETG was estimated according to self-reported antiepileptic drug use. Results We identified 291 PWE along with 182 controls. The age-standardised prevalence of active epilepsy was 2.91/1,000. All PWE had convulsive epilepsy, 71.5% being of focal onset. Risk factors for epilepsy were a positive family history (OR 29.0), febrile convulsions in childhood (OR 20.4) and obstetric complications (OR 3.4). Eight cases had NCC; six cases and no controls had antibodies to Taenia solium (p=0.036). PWE were less likely to have completed primary education (OR 0.3) and were more likely to be divorced or separated (OR 7.7). The ETG was 68.4%. Conclusions This is one of the largest community-based studies of epilepsy from SSA to date. The large proportion of focal-onset epilepsy suggests a considerable burden of acquired epilepsy. The high ETG may reflect the stigma experienced by PWE in this population.