Enhancing the Well-being of the Elderly: evidence from China on the role of Health Investment.

Subjective well-being (SWB) is increasingly recognized as a critical indicator of healthy ageing. While prior studies highlight the importance of health behaviours, few examine how multidimensional health investments influence SWB across different levels of well-being. This paper explores the relationship between health investment and SWB among older adults in China, using data from the 2018 Chinese Longitudinal Healthy Longevity Survey. Health investment is categorized into four domains: nutrition, healthcare access (insurance coverage and health product use), lifestyle behaviours (including exercise, smoking, and drinking), and living environment (access to clean drinking water). Quantile regression models are applied to assess heterogeneous effects across the SWB distribution, while mediation analysis investigates the role of self-rated health and functional health (ADL) as potential pathways. Results show that the positive effects of nutrition and exercise are most pronounced among individuals with lower SWB, while smoking and drinking exhibit stronger negative associations in this group. Mediation results suggest that perceived health plays a more consistent role than functional status in translating health investment into higher well-being. The impact of insurance is observed primarily through interaction effects, magnifying benefits from healthy behaviours and buffering risks from harmful ones. These findings point to the need for equity-sensitive ageing policies that target both health behaviours and social protection. Specifically, integrating social work and behavioural counselling into primary health outreach may help address substance-related risks and psychological vulnerabilities among the elderly. This evidence has wider relevance for ageing societies, particularly in low- and middle-income countries aiming to align health system goals with subjective well-being outcomes.