South Africa as a country has been experiencing a quadruple burden of disease, and about mortality, non-communicable diseases (NCDs) have been leading at 43% followed by Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome (HIV/AIDS) and Tuberculosis (TB) at 34%; other communicable diseases (and perinatal conditions, maternal causes, and nutritional deficiencies) at 14% and injuries at 10% (1). According to the World Health Organization (WHO) estimates from 2016, NCDs accounted for 71% of all-cause mortality globally. More recent WHO data indicate that by 2021, this had risen to approximately 75%, with 18 million NCD deaths occurring before the age of 70 (2–4). Over the last two decades, the burden of NCDs has increased in Sub-Saharan Africa (SSA) owing to rising rates of cardiovascular risk factors such as unhealthy diets, lack of physical activity, hypertension, obesity, diabetes, dyslipidaemia, and air pollution (5). It has been estimated that almost 60% of all deaths in South Africa were due to NCDs in 2018 (6).

Inequality in health refers to disparities in health status or access to health services between populations, with one group being better off than the other (7). Social determinants such as socioeconomic status, education level, and race or ethnicity are key risk factors of NCDs that influence a person's access to care (8). People from minority and underprivileged populations may have worse results due to a lack of access and a delay in accessing care (9). One of the leading public health problems worldwide is the disparity in health between demographic classes (10). A person's socioeconomic status results from several characteristics and variables, including their education, income, employment status, location of residence, housing, the characteristics of their neighborhoods, their gender, and their ethnicity (11). Depending on their influence over lifestyle choices, health expectations, health-seeking behaviors, and access to healthcare (12). These factors can affect the distribution of health outcomes within and between societies and result in unjust and avoidable disparities when it comes to health outcomes (13). Socioeconomic status is recognized as a key contributor to the development of NCDs, not only in South Africa but globally. In high-income nations, social disparities and their association with the distribution and treatment of NCDs and associated risk factors have been thoroughly documented (14).

The growing prevalence of NCDs in South Africa has been linked to four lifestyle risk factors: poor diet, physical inactivity, tobacco use, and excessive alcohol consumption (15, 16). A noteworthy body of research links socioeconomic disadvantage, psychosocial stress, and risk behaviors for NCDs. This study aimed to investigate the socioeconomic inequalities in the prevalence of chronic NCDs (hypertension and diabetes) risk factors among adults residing in the Dikgale, Mamabolo and Mothiba (DIMAMO) Health and Demographic Surveillance Site (HDSS) in Limpopo Province, South Africa.

This study examined socioeconomic inequalities in the prevalence of chronic NCD risk factors among adults in the DIMAMO HDSS in Limpopo Province, South Africa. The study population was relatively young, with most participants aged 18–50 years, a predominance of women, and a high unemployment rate, particularly among females. Educational attainment was mostly secondary level, and over 40% of participants belonged to lower socioeconomic quintiles. These sociodemographic attributes collectively mirror the broader socioeconomic profile of many rural South African communities, where limited employment opportunities and educational attainment contribute to poverty and restricted access to healthcare and healthy lifestyle options (18, 20).

The findings revealed disparities in the distribution of NCD risk factors across socioeconomic strata. While behavioral risk factors such as smoking, physical inactivity, and low fruit and vegetable intake were more common among individuals in lower socioeconomic groups, metabolic risk factors such as diabetes were more concentrated among wealthier participants. This pattern underscores a complex dual burden of NCD risk factors, shaped by both material deprivation and lifestyle transitions, reflecting both material deprivation and lifestyle transitions associated with urbanization and changing social determinants of health (21).

The interpretation of self-reported hypertension and diabetes warrants caution. These outcomes are likely subject to underdiagnosis, particularly among individuals in lower socioeconomic groups who may have limited access to routine screening services and healthcare services. Conversely, higher reported prevalence among wealthier participants may partly reflect better healthcare access and greater diagnostic awareness rather than true differences in underlying disease burden. Such differential reporting may partly explain the observed pro-rich concentration of diabetes in this study.

The predominance of younger adults in the sample is notable because this age group represents a critical window for NCD prevention. Similar to findings from the 2023 South African Demographic and Health Survey, younger adults often report high rates of behavioral risks, including tobacco and alcohol use, which can predispose them to metabolic disease later in life (22). The high unemployment and low income levels observed likely exacerbate vulnerability to NCD risk factors through psychosocial stress and reduced capacity to adopt healthier diets (21). Thus, the socioeconomic context of young adults in this setting may magnify their risk trajectories over time.

Gender differences were pronounced; men reported higher smoking and alcohol consumption rates, while women were more likely to be unemployed and physically inactive. These findings mirror trends reported in other African HDSS populations, where gender norms and socioeconomic constraints influence risk behaviors differently (23). In 2020, a study in rural Kenya, men exhibited significantly higher engagement in harmful alcohol and tobacco use, while women were more affected by obesity and physical inactivity (24). These parallels suggest that gendered risk patterns in this study are consistent with regional trends shaped by social roles and access to resources.

The observed concentration of smoking, physical inactivity, and poor dietary habits among individuals in lower SES groups aligns with previous studies in South Africa and other low- and middle-income countries (LMICs) that link poverty to unhealthy behavioral patterns (18, 21). Likewise, a study in Nigeria found that individuals from poorer communities exhibited higher rates of smoking and unhealthy dietary habits due to limited access to health information and economic constraints in food choices (25). Similar patterns were observed in Kenya's national STEPS survey, where unhealthy behaviors were more concentrated among rural and low-income populations (26). These consistencies reinforce the persistent influence of structural deprivation on behavioral risk exposures.

In contrast, the concentration of diabetes among higher socioeconomic groups in this study is consistent with the epidemiological transition observed in sub-Saharan Africa (5). A study of income-based inequalities across four South Asian countries found that higher income groups had a greater prevalence of NCD risk factors, including diabetes, and greater inequities in preventive care services (27). Similarly, in South Africa between 2003 and 2016, SES gradients in diabetes prevalence showed that higher SES was associated with greater prevalence of self-reported diabetes (28). In Ghana, diabetes prevalence was significantly higher among educated and urban residents compared to poorer rural populations (29). As income increases, individuals often adopt more sedentary lifestyles and consume energy-dense diets, contributing to higher rates of obesity and diabetes. This suggests that as SES improves, exposure to energy-dense diets and sedentary lifestyles may increase, leading to metabolic disorders even in contexts of overall improved living standards.

Although hypertension was the most prevalent NCD risk factor in this population, its distribution across socioeconomic quintiles did not show a statistically significant pattern. This finding is consistent with a systematic analysis of the burden of NCDs across European countries; SES inequalities in some conditions were evident, while in others they were less consistent (30). Similar results have been reported in other sub-Saharan African studies (23, 31), suggesting that hypertension may now be pervasive across all socioeconomic strata, reflecting its multifactorial aetiology involving stress, diet, genetics, and healthcare access. In rural communities, limited screening services and low awareness may suppress diagnosis among low-income groups, while in higher SES groups, better access to healthcare may lead to higher detection rates. Similar findings were reported in a national South African survey, which found no consistent socioeconomic gradient in hypertension prevalence (32). The coexistence of high hypertension prevalence across all SES levels suggests that both prevention and management strategies should target the entire population, regardless of wealth status.

The divergence in the socioeconomic patterning of behavioral and metabolic risk factors in this study supports the “inverse equity hypothesis”, which posits that new health risks and interventions initially benefit higher SES groups but later shift to lower SES groups as exposure and awareness spread. Behavioral risks such as tobacco and alcohol use may initially be more prevalent among the affluent but become increasingly concentrated among the poor as interventions target wealthier populations. Conversely, metabolic risks such as diabetes and hyperlipidaemia may initially rise among the wealthy before diffusing across socioeconomic strata as lifestyles change. Recent literature also suggests that social determinants such as material needs insecurity are strongly associated with cardiovascular risk in rural South Africa (33). A 2024 study of older adults in Mpumalanga Province found that material needs security was associated with cardiovascular risk factors (33). This underscores that beyond simple income or asset-based SES measures, deeper structural determinants matter for metabolic and behavioral risk profiles.

These findings have several important implications for NCD prevention and control. First, interventions targeting behavioral risk factors must prioritize low-income populations through community-based education, health promotion, and fiscal policies (e.g., tobacco taxation and regulation of unhealthy foods). Evidence from the South African sugar-sweetened beverage tax demonstrates that fiscal measures can reduce consumption of unhealthy products, particularly among low-income populations (34). A South African study of processed-food consumption found significant associations between processed foods and NCDs (35). Such evidence reinforces the value of population-level policies that disproportionately benefit disadvantaged groups. Second, screening programs for diabetes and hypertension should be expanded to ensure early detection across all SES groups, particularly in rural settings. Third, addressing the structural determinants of health, such as poverty, unemployment, and education, is critical to reducing NCD inequalities. The integration of social protection programs with primary health care could improve both health outcomes and equity. Moreover, strengthening surveillance systems like DIMAMO HDSS provides valuable data for monitoring health disparities over time.

The study demonstrates clear socioeconomic inequalities in the prevalence of NCD risk factors in a rural South African population. behavioral risks such as smoking, poor diet, and physical inactivity are concentrated among the poor, while metabolic risks like diabetes are more common among the affluent. The findings support targeted community-based interventions to reduce behavioral risk factors among low socioeconomic groups, alongside expanded screening and early detection programmes for hypertension and diabetes across all SES strata, including higher-income populations. Addressing NCD inequalities will also require intersectoral actions integrating social protection, employment creation, and educational opportunities to address upstream determinants of health. Strengthening community-level health promotion and surveillance systems will be essential to achieving equitable NCD prevention and control in South Africa. Future studies should incorporate objective biometric measurements, such as blood pressure and blood glucose testing, to improve accuracy and reduce socioeconomic reporting bias.