Obesity and Hypertension in South African Adults: A Scoping Review of Prevalence, Association, and Moderating Factors (Age, Sex, Urban/Rural Residence, and Adiposity Measures)

Obesity and hypertension are among the major contributors to the prevalence of non-communicable diseases in South Africa. The link between obesity and hypertension poses a major risk for mortality due to cardiovascular disease. This scoping review study set out to provide a mapping of the current literature on the link between obesity and hypertension among adult South Africans, comparing the applicability of BMI measurements against central adiposity indices (waist circumference and waist-to-height ratio) and considering potential moderators such as age, gender, and urbanization. A search for eligible studies was conducted on PubMed (n = 149), Google Scholar (n = 235), ScienceDirect (n = 55), Cochrane Library (n = 10), and Scopus (n = 5) up to 25 February 2026. The PCC (Population, Concept, Context) framework guided study selection: Population—adults (15–70 years) in South Africa; Concept—prevalence, association, and moderators of obesity and hypertension; Context—South African community and clinical settings. A total of 25 studies were included in the review. The prevalence of general and central obesity was found to be higher in females, with rates of 60% and 90–95%, respectively. The prevalence of hypertension varied between 18% and 70%. A stronger correlation was observed in the case of WHtR with systolic blood pressure (r = 0.209, P = 0.04) and diastolic blood pressure (r = 0.279, P = 0.006). 1.75-fold increased odds of having hypertension were observed with an elevated BMI. This scoping review maps evidence showing that South Africa faces high rates of both obesity and hypertension. In studies that directly compared adiposity measures, central adiposity measures (WC and WHtR) were more strongly associated with hypertension than BMI, although not all studies conducted direct comparisons. Sex, age, and urbanization showed consistent patterns of association with the obesity–hypertension relationship. Age showed the most consistent pattern across studies, but formal interaction testing was performed in only one study, and no study formally tested urban/rural residence as an effect modifier. Identified areas for further research include a lack of longitudinal research beyond major cities, a limited number of studies on the impact of socioeconomic status as a moderator of this relationship, and a lack of interventions to test causality.