Socio-economic correlates with the prevalence and onset of diabetes in South Africa: Evidence from the first four waves of the National Income Dynamics Study

We make use of multiple waves of National Income Dynamics Study data, from 2008 to 2015, to investigate the socio-economic factors that correlate with the prevalence and onset of diabetes. Our analysis follows a cohort of 3470 older adults aged forty and above, who are interviewed four times over a six-year period. We use linear probability models and estimate the likelihood of diabetes as a function of age, race, gender, education, income, exercise, and obesity. Our primary findings are that age and obesity correlate strongly with diabetes, while income does not have a statistically significant effect, conditional on the other covariates. Our regression estimates indicate that, of individuals who reported not being diabetic in Wave 1, those who were obese and morbidly obese were 12.9 and 16.7 percentage points more likely to have experienced the onset of diabetes respectively, relative to those with a BMI in the healthy range. In addition, frequent exercise does appear to have a slight protective effect against the onset of diabetes, and there is some evidence that better educated people have a lower risk of onset of the disease.