摘要：Objectives. We examined the association between social cohesion and mortality in a sample of older adults in Japan. Methods. Data were derived from a cohort study of elderly individuals (65–84 years) in Shizuoka Prefecture; 14 001 participants were enrolled at baseline (1999) and followed up in 2002, 2006, and 2009. Among the 11 092 participants for whom we had complete data, 1427 had died during follow-up. We examined the association between social cohesion (assessed at both the community and individual levels) and subsequent mortality after control for baseline and time-varying covariates. We used clustered proportional hazard regression models to estimate hazard ratios (HRs) and confidence intervals (CIs). Results. After control for individual characteristics, individual perceptions of community cohesion were associated with a reduced risk of all-cause mortality (HR = 0.78; 95% CI = 0.73, 0.84) as well as mortality from cardiovascular disease (HR = 0.75; 95% CI = 0.67, 0.84), pulmonary disease (HR = 0.66; 95% CI = 0.58, 0.75), and all other causes (HR = 0.76; 95% CI = 0.66, 0.89). However, no statistically significant relationship was found between community cohesion and mortality risk. Conclusions. Among the elderly in Japan, more positive individual perceptions of community cohesion are associated with reduced risks of all-cause and cause-specific mortality. A growing body of research has focused on social cohesion as a determinant of population health. 1 Higher levels of community social cohesion—characterized by closely knit social relationships among residents with strong mutual trust and reciprocity—have been linked to better health outcomes such as lower mortality rates and higher self-rated health. 1–10 However, prospective studies of social cohesion and health remain sparse, and there is continuing debate about whether such associations are driven by individual residents’ psychological perceptions about their communities or by the characteristics of the communities per se. 11 In other words, cohesive communities may be healthier either because residents are psychologically healthier and express trust toward their neighbors (a compositional effect) or because the community social environment promotes health via group-level processes such as the ability to undertake collective action, for example mobilizing local volunteers to participate in health promotion activities (a contextual effect). Multilevel analytical techniques are required to tease out the compositional effects of community cohesion from its contextual effects. To date, there has been stronger empirical support for an association between individual-level perceptions of social cohesion and health outcomes and less evidence for a community-level contextual effect. 11 Japanese society has historically been characterized by high levels of social cohesion. The reasons for this include the roughly 2 centuries of isolationism (from 1633 until 1853) enforced by the Tokugawa shogunate (a feudal Japanese military government), as well as the comparative ethnic homogeneity of the Japanese population. 12 Recent multilevel studies conducted in Japan suggest an association between community social cohesion and improved health outcomes, including higher self-rated health, 13 a lower risk of depression, 14 and a lower incidence of functional disabilities. 15 Two of these studies were conducted among older Japanese people. 13,15 However, according to a systematic review of multilevel studies of income inequality, prospective studies remain sparse, and more evidence is needed to establish the robustness of the association between income inequality and population health. 11 With few exceptions, the empirical evidence linking community social cohesion to health has been based on cross-sectional study designs, and there is a dearth of longitudinal evidence. We examined the long-term associations between social cohesion and mortality in a sample of older Japanese adults.
