Examining gender differences in adult mortality mediated by household poverty in two urban slums of Nairobi

Abstract

In sub-Saharan Africa, adult mortality estimates mainly obtained from nationally representative surveys such as Demographic and Health Surveys show discrepancies in all-cause mortality between men and women. It is important to understand factors that explain these differences. Using data for adults aged ≥15 years from the Nairobi Urban Demographic Health Surveillance System (NUHDSS), this study assesses whether gender differences in all-cause mortality are mediated through household poverty. We used the generalised structural equation model, a unified framework that allows to calculate both direct and indirect effects of exposure on outcome. Results show that overall mortality rates in 151,865 individuals were 32.9 and 28.4 per 100 person years among men and women, respectively during median(IQR) follow-up of 7.3 (3.7, 10.6) years. The effects of gender on mortality decreased with age. We observed a male versus female aOR 1.39 [95% CI (1.25, 1.53)] which represents a higher odds of dying among men compared to women in the 15–35 age group, but lower odds of dying in the age group 35–60 years and >60 years, aOR 0.90 [95% CI (0.81, 0.99)], aOR 0.91 [95% CI (0.73, 1.12)], respectively. We estimated the direct effect of gender on mortality mediated through household poverty but the mediated effects were marginal.All estimates are adjusted for age, slum area, education level and ethnicity. In summary, differences in mortality between men and women decrease with age, and partly are mediated by household poverty. Given that differences in mortality between men and women who share the same household decreases with age, it is essential for future interventions aimed at reducing the gap in gender mortality particularly in older age groups, to consider other factors that interact with poverty.