Socioeconomic, health, and social connectedness factors associated with self-rated health of octogenarians and nonagenarians in South Korea: Urban and rural comparison

Background The aging population, including octogenarians (aged 80–89) and nonagenarians (aged 90–99), is rapidly increasing. Understanding their self-rated health in urban and rural settings is vital for public health policy development. This study examined factors associated with self-rated health among octogenarians and nonagenarians across urban and rural areas of South Korea. Methods We analyzed data of 21,896 older adults (aged 80–99) from the 2023 Korea Community Health Survey. Self-rated health was assessed on a 5-point scale and categorized as "good" or "poor." Variables included age, residence area (urban/rural), sociodemographic characteristics, health behaviors, healthcare utilization, morbidity, and social interactions. Descriptive statistics were used to examine variable distributions, and logistic regression models identified factors associated with self-rated health in each age group and residential area. Results Among octogenarians, 18.7% in urban areas reported good self-rated health, compared to 15.0% in rural areas. In contrast, a smaller proportion of nonagenarians reported good self-rated health in urban areas (13.6%) than in rural areas (14.7%). Octogenarians in both rural and urban areas with higher education (urban odds ratio [OR] = 1.15, 95% CI = 1.07–1.24; rural OR = 1.15, 95% CI = 1.10–1.22) and higher income (urban OR = 1.18, 95% CI = 1.07–1.31; rural OR = 1.09, 95% CI = 1.01–1.18) reported better self-rated health. However, this association was less pronounced among nonagenarians. Characteristics such as regular walking (OR range 1.41 [95% CI = 1.23–1.62] among rural octogenarians to 2.25 [95% CI = 1.89–2.69] among urban nonagenarians), good self-rated oral health (OR range 2.48 [95% CI = 1.98–4.00] among rural nonagenarians to 3.50 [95% CI = 3.01–4.07] among urban octogenarians), and participation in social activities (OR range 1.24 [95% CI = 1.09–1.41] among rural nonagenarians to 1.67 [95% CI = 1.29–2.16] among urban octogenarians) were consistently associated with good self-rated health across all age groups in both rural and urban areas. Conclusions Characteristics associated with self-rated health differed significantly between octogenarians and nonagenarians in rural and urban areas. Public health strategies must support health-promoting behaviors such as regular walking, enhance oral health services, improve healthcare accessibility, reduce environmental stressors, and strengthen social support networks to promote health among octogenarians and nonagenarians.