Data from: Lifestyle and socio-economic inequalities in diabetes prevalence in South Africa: a decomposition analysis

Background: Inequalities in diabetes are widespread and are exacerbated by
differences in lifestyle. Many studies that have estimated inequalities in
diabetes make use of self-reported diabetes which is often biased by
differences in access to health care and diabetes awareness. This study
adds to this literature by making use of a more objective standardised
measure of diabetes in South Africa. The study estimates socio-economic
inequalities in undiagnosed diabetes, diagnosed diabetes (self-reported),
as well as total diabetes (undiagnosed diabetics + diagnosed diabetics).
The study also examines the contribution of lifestyle factors to diabetes
inequalities in South Africa. Methods: This cross sectional study uses
data from the 2012 South African National Health and Nutrition Examination
Survey (SANHANES-1) and applies the Erreygers Concentration Indices to
assess socio-economic inequalities in diabetes. Contributions of lifestyle
factors to inequalities in diabetes are assessed using a decomposition
method. Results: Self-reported diabetes and total diabetes (undiagnosed
diabetics + diagnosed diabetics) were significantly concentrated amongst
the rich (CI = 0.0746; p < 0.05 and CI = 0.0859; p < 0.05).
The concentration index for undiagnosed diabetes was insignificant but
pro-poor. The decomposition showed that lifestyle factors contributed 22%
and 35% to socioeconomic inequalities in self-reported and total diabetes,
respectively. Conclusion: Diabetes in South Africa is more concentrated
amongst higher socio-economic groups when measured using self-reported
diabetes or clinical data. Our findings also show that the extent of
inequality is worse in the total diabetes outcome (undiagnosed diabetics +
diagnosed diabetics) when compared to the self-reported diabetes outcome.
Although in comparison to other determinants, the contribution of
lifestyle factors was modest, these contributions are important in the
development of policies that address socio-economic inequalities in the
prevalence of diabetes.