JOB STRAIN, SOCIAL SUPPORT AT WORK, AND INCIDENCE OF MYOCARDIAL-INFARCTION

Objectives-The combination of high psychological job demands and low d ecision latitude thigh job strain) has been associated with an increas ed risk of coronary heart disease. It has been proposed that this may also be the case for low social support at work. The aim of this study was to analyse the relations between these psychosocial factors and i ncidence of myocardial infarction. Methods-Associations between psycho social work characteristics and incidence of myocardial infarction was investigated through a population based case-control study. The study base comprised employed men and women in five Swedish counties during the years 1976-84. Cases of first myocardial infarction were identifi ed from hospital discharge registers and death records from outside ho spital, controls were selected through a random sample, and psychosoci al work environment was assessed through a job exposure matrix on the basis of the occupation in the 1970 and 1975 censuses. Results-An incr eased incidence of myocardial infarction was found for men and women i n occupations characterised by low decision latitude. For men this inc rease was seen primarily in combination with high psychological demand s thigh job strain) and low social support at work. Younger men (30-54 years of age) in occupations with both high job strain and low social support at work had a relative risk of 1.79 (95% confidence interval (95% CI) 1.22 to 2.65) compared with subjects in low strain and high s ocial support jobs after controlling for age, county of residence, and socioeconomic group. Conclusions-Our results indicate that jobs chara cterised by low decision latitude, high job strain, or low social supp ort at work may be associated with an increased risk of acute myocardi al infarction. If these associations are causal they may be of substan tial importance from the point of view of workers' health.