Factors associated with socioeconomic inequalities in the prevalence of chronic NCD risk factors in the DIMAMO surveillance site, South Africa

Non-communicable diseases (NCDs) are a leading cause of morbidity and mortality globally, with a disproportionate burden in low- and middle-income countries and among socioeconomically disadvantaged populations. Understanding socioeconomic inequalities in NCD risk factors is important for developing targeted prevention strategies. This study assessed factors associated with socioeconomic inequalities in chronic NCD risk factors among adults in the DIMAMO Health and Demographic Surveillance System (HDSS) in rural South Africa. A cross-sectional survey was conducted among 398 adults aged ≥18 years attending primary healthcare facilities within the DIMAMO HDSS catchment area. SES was measured using an asset-based wealth index derived through principal component analysis and categorized into quintiles. Data on tobacco use, harmful alcohol use, physical inactivity, low fruit and vegetable intake, high salt intake, self-reported hypertension, and diabetes, were collected using adapted WHO STEPS and SAGE questionnaires. Crude and adjusted prevalence ratios (PRs and aPRs) were estimated using modified Poisson regression with robust standard errors. SES was not significantly associated with hypertension after adjustment. Participants in the richer (aPR = 1.58; 95% CI: 1.03-2.41) and richest (aPR = 1.78; 95% CI: 1.11-2.85) SES quintiles had a higher prevalence of harmful alcohol use than those in the poorest quintile. Physical inactivity was less prevalent among participants in the middle, richer, and richest quintiles. Tobacco use was less prevalent among females and participants with secondary or tertiary education. Self-reported diabetes tended to be more prevalent among richest quintile, although the association was not statistically significant. Age, sex, educational attainment, and employment status were associated with several NCD risk factors. Socioeconomic inequalities in NCD risk factors were evident in this rural population. Higher SES was associated with harmful alcohol use and a lower physical inactivity. These findings highlight complex socioeconomic patterning of NCD risk factors and support context-specific interventions and longitudinal research.