Young adult and middle age mortality in Butajira demographic surveillance site, Ethiopia: lifestyle, gender and household economy

BACKGROUND: Public health research characterising the course of life through the middle age in developing societies is scarce. The aim of this study is to explore patterns of adult (15–64 years) mortality in an Ethiopian population over time, by gender, urban or rural lifestyle, causes of death and in relation to household economic status and decision-making. METHODS: The study was conducted in Butajira Demographic Surveillance Site (DSS) in south-central Ethiopia among adults 15–64 years old. Cohort analysis of surveillance data was conducted for the years 1987–2004 complemented by a prospective case-referent (case control) study over two years. Rate ratios were computed to assess the relationships between mortality and background variables using a Poisson regression model. In the case-referent component, odds ratios (95% confidence intervals) were used to assess the effect of certain risk factors that were not included in the surveillance system. RESULTS: A total of 367 940 person years were observed in a period of 18 years, in which 2 860 deaths occurred. One hundred sixty two cases and 486 matched for age, sex and place of residence controls were included in the case referent (case control) study. Only a modest downward trend in adult mortality was seen over the 18 year period. Rural lifestyle carried a significant survival disadvantage [mortality rate ratio 1.62 (95% CI 1.44 to 1.82), adjusted for gender, period and age group], while the overall effects of gender were negligible. Communicable disease mortality was appreciably higher in rural areas [rate ratio 2.05 (95% CI 1.73 to 2.44), adjusted for gender, age group and period]. Higher mortality was associated with a lack of literacy in a household, poor economic status and lack of women's decision making. CONCLUSION: A complex pattern of adult mortality prevails, still influenced by war, famine and communicable diseases. Individual factors such as a lack of education, low economic status and social disadvantage all contribute to increased risks of mortality.