Determinants of Obesity among Community-dwelling Persons 80 Years and Older: Longitudinal Evidence from Rural South Africa, 2015–2022

Background and Aim: Few studies have looked closely at the prevalence and contributing factors of obesity in adults 80 years of age and older. This study set out to identify these characteristics and their prevalence using 3-wave longitudinal data from South Africa. Materials and Methods: Longitudinal data from three waves of the “Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community in South Africa (HAALSI)” (2015–2022) were utilized. The sample was limited to community members who were 80 years of age or older and who had full height and weight measurements (analytic sample: n = 1252 observations). The World Health Organization’s definition of obesity was body mass index ≥ 30 kg/m 2 . Random effects (RE) logistic regressions were utilized to estimate the determinants of obesity. Results: The prevalence of obesity was 20.9%. RE regressions showed that the probability of obesity increased with higher wealth status, transition to noncurrent tobacco use, having hypertension and diabetes, and decreased with male sex and having been diagnosed with kidney disease. Age, educational level, marital status, living arrangement, fruit and vegetable intake, nonheavy alcohol use, depressive symptoms, functional limitations, cardiovascular disease, and impaired cognition were not associated with obesity. Conclusions: This long-term study advances our understanding of the factors that lead to obesity in persons 80 years of age and older. Obesity may be decreased by methods for managing diabetes, hypertension, and tobacco use.