Stroke mortality in urban and rural Tanzania. Adult Morbidity and Mortality Project

Most data for stroke mortality in sub-Saharan Africa are hospital based. We aimed to establish the contribution of cerebrovascular disease to all-cause mortality and cerebrovascular disease mortality rates in adults aged 15 years or more in one urban and two rural areas of Tanzania.

Regular censuses of the three surveillance populations consisting of 307,820 people (125,932 aged below 15 years and 181,888 aged 15 or more) were undertaken with prospective monitoring of all deaths arising in these populations between June 1, 1992 and May 31, 1995. Verbal autopsies were completed with relatives or carers of the deceased to assess, when possible, the cause of death.

During the 3-year observation period 11,975 deaths were recorded in the three surveillance areas, of which 7629 (64%) were in adults aged 15 years or more (4088 [54%] of these in men and 3541 [46%] in women). In the adults, 421 (5.5%) of the deaths were attributed to cerebrovascular disease, 225 (53%) of these in men and 196 (47%) in women. The yearly age-adjusted rates per 100,000 in the 15-64 year age group for the three project areas (urban, fairly prosperous rural, and poor rural, respectively) were 65 (95% CI 39-90), 44 (31-56), and 35 (22-48) for men, and 88 (48-128), 33 (22-43), and 27 (16-38) for women, as compared with the England and Wales (1993) rates of 10.8 (10.0-11.6) for men and 8.6 (7.9-9.3) for women.

We postulate that the high rates in Tanzania were due to untreated hypertension. Our study assessed mortality over a single time period and therefore it is not possible to comment on trends with time. However, ageing of the population is likely to lead to a very large increase in mortality from stroke in the future.