摘要：Objectives. We examined the association between workplace social capital and all-cause mortality in a large occupational cohort from Finland. Methods. We linked responses of 28 043 participants to surveys in 2000 to 2002 and in 2004 to national mortality registers through 2009. We used repeated measurements of self- and coworker-assessed social capital. We carried out Cox proportional hazard and fixed-effects logistic regressions. Results. During the 5-year follow-up, 196 employees died. A 1-unit increase in the mean of repeat measurements of self-assessed workplace social capital (range 1–5) was associated with a 19% decrease in the risk of all-cause mortality (age- and gender-adjusted hazard ratio [HR] = 0.81; 95% confidence interval [CI] = 0.66, 0.99). The corresponding point estimate for the mean of coworker-assessed social capital was similar, although the association was less precisely estimated (age- and gender-adjusted HR = 0.77; 95% CI = 0.50, 1.20). In fixed-effects analysis, a 1-unit increase in self-assessed social capital across the 2 time points was associated with a lower mortality risk (odds ratio = 0.81; 95% CI = 0.55, 1.19). Conclusions. Workplace social capital appears to be associated with lowered mortality in the working-aged population. In the past 2 decades, interest has grown in the health effects of social capital, defined as the features of social structures, such as levels of interpersonal trust and norms of reciprocity and mutual aid, that act as resources for individuals and facilitate collective action. 1 – 3 In the literature, social capital has been conceptualized (and measured) both at the individual level and at the group level. 4 , 5 At the individual level, the most common approach has been to measure individual perceptions of the level of cohesion or solidarity in the group to which the individual belongs. At the group level, the focus is on the collective (e.g., neighborhood or workplace). Thus, a common practice has been to aggregate the individual responses from surveys to the collective. Some authors have also measured social capital through objective indicators that are not dependent on respondent perceptions, such as density of civic associations within a community. 6 Another approach derives measures of social capital from social network analysis. 7 Adding to cross-sectional ecological analyses, 8 at least 7 prospective studies in nonoccupational settings have examined the association between social capital and mortality among the working-aged population through at least 1 indicator of social capital. 9 – 15 Findings from those studies have been mixed, although the preponderance of evidence favors a weak inverse association. Several factors may have contributed to inconsistent evidence. For example, previous studies on mortality have focused on social capital in residential or geographical areas rather than in occupational settings, although recent research has emphasized the importance of the evaluation of workplace social capital to explain variations in employees' health. 16 – 19 Indeed, for working populations, sources of variation in social capital are likely to be found in settings where people spend an increasing portion of their daily lives: workplaces. 20 , 21 Furthermore, because all these studies assessed social capital at only 1 time point, further data with repeated measurements of social capital are needed to strengthen the evidence. The Finnish Public Sector Study had at least 3 strengths that addressed the question of workplace social capital and mortality. First, it provided unique individual- and workplace-level survey data from a large occupational cohort linked to comprehensive national mortality registers. The linkage was complete, minimizing any bias related to selective sample retention. Second, the data included repeated assessments of workplace social capital, which enabled the determination of both repeated exposure and change in workplace social capital. Third, both self- and coworker-assessed social capital were available. This information helped to address reporting bias. We used these data to examine the hypothesis that repeated exposure to low workplace social capital and adverse changes in social capital are associated with increased mortality, corresponding to previous findings on workplace social capital and self-rated health and depression, 22 important correlates of all-cause mortality. 23
