Mediating and Moderating Effects of Internet Use on Urban-Rural Disparities in Health Among Older Adults: Nationally Representative Cross-Sectional Survey in China

Background: The urban-rural disparities in health outcomes in China are remarkable. The internet has shown the potential to reduce the likelihood of contracting a disease by increasing disease knowledge. However, little is known about the effects of internet use in alleviating health inequities between urban and rural areas. Objective: This study aimed to examine the mediation and moderation of health disparities between urban and rural older adults through internet use. Methods: A total of 8223 respondents were selected from the China Health and Retirement Longitudinal Study 2018 data set. Basic activities of daily living, a brief Community Screening Instrument for Dementia, and the Centre for Epidemiologic Studies Depression Scale were used to measure functional disability, cognitive function, and depressive symptoms, respectively. Logistic regressions testing "internet usexurban-rural status" interactions for moderation and Karlson-Holm-Breen decomposition for mediation were performed. Results: Internet use moderated the urban-rural disparities in cognitive function (odds ratio 7.327, 95% CI 3.011-17.832) and depressive symptoms (odds ratio 1.070, 95% CI 1.037-1.787), but the moderating effects were significant only for those using the internet daily. Karlson-Holm-Breen results showed the suppression effects of using the internet daily (beta=.012, 95% CI .002-.021) on the association between urban-rural status and cognitive function. The urban-rural inequality in depressive symptoms was partially attributed to the disparity in internet use (beta=-.027, 95% CI -.043 to -.009). Conclusions: The urban-rural inequalities in mental health are partially attributable to disparities in the prevalence of internet use between the 2 groups. However, using the internet is more beneficial for the psychological health of rural users, thereby alleviating the urban-rural disparities in health. Providing convenient channels for rural older adults to use the internet, improving the ability of rural users to effectively use the internet, and promoting internet popularity in rural areas are effective approaches to reducing urban-rural health inequalities.