The impact of physical activity on household out-of-pocket medical expenditure among adults aged 45 and over in urban China: The mediating role of spousal health behaviour.

Background: Increasing medical expenditure is viewed as one of the critical challenges in the context of population ageing. Physical activity (PA), as a primary prevention strategy for promoting health, is considered as an effective way to curb the excessive growth in medical expenditure. This study aimed to analyze the association between PA and the household out-of-pocket medical expenditure (HOPME) among Chinese urban adults aged 45 and over, and to explore the mediating role of spousal health behaviour. Methods: This study analyzed a nationally longitudinal survey: 2014-2018 China Family Panel Studies (CFPS). Fixed effects regression model was applied to estimate the association between PA and annual HOPME. Sobel model was utilized to test the mediating effect. Results: (1) PA was negatively associated with the annual HOPME among urban resident aged 45 and over in China. Exercising 1-5 times per week and maintaining the duration of each exercise session at 31-60 min were effective in reducing annual HOPME. (2) Spousal PA played a significant mediating role in the relationship between respondent's PA and annual HOPME. (3) The negative association between the respondent's PA and HOPME were found among women and those aged between 45 and 65, so was the mediating effect of spouse's PA. Conclusion: Individual PA not only directly reduces HOPME but also indirectly contributes to this reduction by enhancing the PA levels of their spouses. To capitalize on these benefits, more actions should be taken to increase the availability of PA facilities, enhance the public awareness of PA's benefits, and encourage residents to consistently engage in regular PA.