Though much evidence indicates that work stress increases the risk of incident of coronary heart disease (CHD), little is known about the role of work stress in the development of recurrent CHD events. The objective of this study was to review and synthesize the existing epidemiological evidence on whether work stress increases the risk of recurrent CHD events in patients with the first CHD. A systematic literature search in the PubMed database (January 1990 -December 2013 for prospective studies was performed. Inclusion criteria included: peer-reviewed English papers with original data, studies with substantial follow-up (> 3 years), end points defined as cardiac death or nonfatal myocardial infarction, as well as work stress assessed with reliable and valid instruments. Meta-analysis using random-effects modeling was conducted in order to synthesize the observed effects across the studies. Five papers derived from 4 prospective studies conducted in Sweden and Canada were included in this systematic review. The measurement of work stress was based on the DemandControl model (4 papers) or the Effort-Reward Imbalance model (1 paper). According to the estimation by meta-analysis based on 4 papers, a significant effect of work stress on the risk of recurrent CHD events (hazard ratio: 1.65, 95% confidence interval: 1.23-2.22) was observed. Our findings suggest that, in patients with the first CHD, work stress is associated with an increased relative risk of recurrent CHD events by 65%. Due to the limited literature, more well-designed prospective research is needed to examine this association, in particular, from other than western regions of the world.
MATERIAL AND METHODSIn order to perform a systematic review and meta-analysis of epidemiological studies we applied internationally established guidelines [23,24]. We searched the PubMed database by applying the following inclusion criteria: -time of publication -January 1990 -December 2013, -study design -a prospective cohort study, -peer-reviewed English-language article with original data, -study subjects -patients with the 1st CHD, -work stress -assessed with reliable and valid instruments, -end points -cardiac death or nonfatal myocardial infarction, -follow-up duration -more than 3 years, -adjustment for relevant confounding factors -such as age, gender, behavior factors, clinical features of CHD, etc. We performed literature search using (combinations of) the following medical subject headings and key words: work stress, psychosocial work characteristics, job strain, effort reward imbalance, coronary heart disease, myocardial infarction, recurrent, patients, prognosis, death. Random-effects modeling was used to perform meta-analysis [25]. We distinguished different levels of work stress and set a group of subjects with a low work stress level as a reference group. Then hazard ratios (HRs) and 95% confidence intervals (CIs) associated with a high work stress level from the selected studies were estimated. We used the Q-test for heterogeneity of the stu...