Genetic risk of Alzheimer's disease is associated with loss of brain network segregation in midlife.

Older adults’ health is influenced not only by individual characteristics but also by the broader social and natural environments in which they live. The World Health Organization’s framework of age-friendly environments emphasizes that community social and physical features are fundamental determinants of physical and mental well-being in later life. Consistent with this perspective, the Decade of Healthy Ageing: Baseline Report identifies social participation and the maintenance of functional capacity within familiar neighborhoods as central policy priorities. Neighborhoods are conceptually defined as the immediate social and physical environment where daily life is conducted, often operationalized within academic literature as the geographical area within walking distance of one’s residence. Empirical evidence from East Asia underscores this conclusion, demonstrating that social environmental conditions are associated with self-rated health among older adults. The neighborhood social environment is defined as the collective social characteristics—such as social networks, social cohesion, and social capital—that shape the health behaviors and psychosocial well-being of residents within a community.Together, these findings highlight the importance of social context as a structural contributor to healthy aging. Similarly, natural environmental characteristics contribute to health in older populations. In particular, access to neighborhood green spaces has been associated with better subjective perceptions of health. Green environments may also serve as settings that facilitate informal social interactions, indirectly fostering well-being. These mechanisms suggest that natural environments influence health through both direct restorative effects and social pathways. Collectively, the evidence indicates that understanding healthy aging requires an integrated framework that considers social and natural environmental influences. Older adults’ social participation has been consistently linked to a wide range of positive health outcomes across international populations. Social participation is broadly defined as a person’s involvement in activities that provide interaction with others in society or the community.Evidence from the European SHARE cohort shows that engagement in social activities and reciprocal support exchanges are associated with higher subjective quality of life among older adults. Social participation has also been found to reduce the risk of chronic conditions and lower depressive symptoms, indicating broader psychosocial and physical health benefits. Exposure to the natural environment demonstrates similarly robust associations with health in later life. Reviews have reported that access to green and natural environments is consistently associated with better subjective health and improved physical and mental well-being among older adults. Proposed mechanisms include increased opportunities for physical activity, stress reduction, and enhanced social interaction facilitated by neighborhood green spaces. Research further suggests that exposure to natural environments may directly promote subjective well-being. Together, these findings indicate that social participation and exposure to the natural environment are complementary domains that influence older adults’ health. Each may operate through distinct yet overlapping behavioral and psychosocial pathways, highlighting the need to consider both environmental dimensions within an integrated framework of healthy aging.