The prevalence of neurological disorders in the 70 years and older population of the Hai district in northern Tanzania

Abstract

Aim To determine the prevalence of neurological disorders in the 70 and over population of the Hai district in northern Tanzania through the production and utilisation of a screening questionnaire, and to describe the subtypes, the level of diagnosis, treatment and associated disability. Introduction There are limited data on neurological disorder and disability prevalence from developing countries despite a highlighted need from the World Health Organisation (WHO). This is partly due to the lack of a feasible and valid screening tool. Methods A screening questionnaire was created and validated for use in the elderly population of a developing country. A cross-sectional two phased epidemiological survey was then performed in the Hai district demographic surveillance site (DSS) (n=161,119). 2232 participants (1/4 of the DSS 70+ population) were screened. Positive responders underwent neurological assessment and were questioned regarding health seeking behaviour. Disability assessment was performed using the Barthel Index. Results The screening questionnaire was validated in one randomly selected village (n=277). Further substantiation was performed in a larger population (n=1955). The sensitivity and specificity were 87.8-97.0% and 90.4-94.9% respectively. In 2232 participants, there were 384 neurological diagnoses amongst 349 people. The age adjusted prevalence of ii neurological diagnoses (95% confidence intervals (CI)) was 168.94/1000 (153.39 to 184.48). 58.6% had sought help for their symptoms, 14.6% had been correctly diagnosed and 10.6% were on appropriate treatment. The age adjusted prevalence of severe and moderate disability was 3.7% and 6.2% respectively. Those with neurological disorders had significantly greater odds of disablement. Conclusions This is the first screening instrument to measure the prevalence of neurological disorders specifically in an elderly population in Sub-Saharan Africa (SSA). It is feasible and valid with a high sensitivity and specificity. This is the first community-based neurological disorder prevalence study specifically in the elderly in SSA. It reveals high neurological morbidity and associated disability and low diagnosis and treatment levels.