Martikainen Pekka, Mäki Netta, Jäntti Markus
Helsinki Collegium for Advanced Studies, University of Helsinki, Helsinki, Finland.
Am J Epidemiol. 2007 May 1;165(9):1070-5. doi: 10.1093/aje/kwm057. Epub 2007 Mar 15.
Unemployment is strongly associated with mortality on the individual level. The reasons for this association are not fully established. The authors estimated the effects of unemployment and workplace downsizing on mortality during periods of low (1989) and high (1994) unemployment in Finland. They used prospective population registration data containing detailed socioeconomic and demographic information on two cohorts aged 35-64 years at the beginning of 1989 (N = 87,317) and 1994 (N = 72,419) followed up for mortality in 1990-1997 and 1995-2002, respectively. Unemployment was found to be associated with a 2.38-fold increase in the hazard of mortality after 1989 and with a 1.25-fold increase after 1994. No excess mortality was observed among those who, at baseline, were employed at workplaces that had experienced large reductions in employment. Furthermore, the association between unemployment and mortality was weaker among those working in establishments that had been strongly downsized. By showing that, in the context of either a high level of unemployment or rapid downsizing, the effects of unemployment on mortality are modest, this study provides strong evidence of unaccounted confounding. Individual-level studies may thus overestimate the causal effects of unemployment on mortality.
在个体层面,失业与死亡率密切相关。这种关联的原因尚未完全明确。作者估计了芬兰在低失业率时期(1989年)和高失业率时期(1994年)失业及工作场所裁员对死亡率的影响。他们使用了前瞻性人口登记数据,这些数据包含了1989年初(N = 87,317)和1994年初(N = 72,419)年龄在35 - 64岁的两个队列的详细社会经济和人口信息,分别对1990 - 1997年和1995 - 2002年的死亡率进行了随访。研究发现,1989年后失业与死亡风险增加2.38倍相关,1994年后与死亡风险增加1.25倍相关。在基线时受雇于就业岗位大幅减少的工作场所的人群中,未观察到额外的死亡率。此外,在经历了大幅裁员的企业中工作的人群,失业与死亡率之间的关联较弱。通过表明在高失业率或快速裁员的背景下,失业对死亡率的影响较小,本研究提供了存在未被考虑的混杂因素的有力证据。因此,个体层面的研究可能高估了失业对死亡率的因果效应。