The prevalence of Parkinson's disease in rural Tanzania

The prevalence of Parkinson's disease (PD) varies worldwide from 7 to 450 per 100,000, and appears low in sub-Saharan Africa (SSA) but few data exist. We conducted a prevalence study of PD in rural Tanzania. A door-to-door study was conducted in the Hai district project area (population 161,071), using a screening questionnaire followed by structured history and examination of positive responders. Diagnosis was based on the UK PD Society Brain Bank Criteria. 33 (23 men) cases of PD were detected, with mean age 74 years (range 38-94). One patient died before the prevalence date. 78% were previously undiagnosed and untreated. Mean duration of symptoms was 5 years, and median Hoehn and Yahr stage 3. Crude prevalence rates were 30/100,000 (men), 11/100,000 (women) and 20/100,000 (combined). The direct age-standardized prevalence rates compared with the UK population were 64/100,000 (men), 20/100,000 (women) and 40/100,000 (combined). These rates are higher than previously reported from SSA, but still lower than the developed world. Many PD patients in SSA may never be diagnosed or treated, with consequent reduction in their life expectancy and quality of life. With the world population ageing PD is predicted to become an increasing problem.