Objectives — To examine the relationship between job strain and incident myocardial infarction and congestive heart failure in a representative population of men and women in Ontario, Canada, over a 15-year period.
Methods — A total of 14,508 respondents having provided responses to either the 2000/2001, 2002, or 2003 cycles of the Canadian Community Health Survey (CCHS) were aged 35 and older at the time and working. After removing respondents with pre-existing heart disease and missing data, our sample totaled 13,291 respondents. Responses were linked to administrative health care and hospitalization data to capture incident cases of myocardial infarction and congestive heart failure up to March 31, 2017. Job control and psychological demands were assessed using 5 items and 2 items respectively. A series of time-to-event regression models were run, adjusting sequentially for socio-demographic variables and health, other psychosocial work exposures, and health behaviours and body mass index.
Results — Over the study period, there were 199,583 person-years of follow-up (median follow-up: 15 years, 233 days). Higher incidence rates were observed for men (6.69 per 100 persons) than for women (2.77 per 100 persons). No clear relationship was observed for demand-control exposures and incidence of myocardial infarction and congestive heart failure in either men or women. After adjustment for socio-demographic factors, pre-existing health conditions, and other psychosocial exposures, the hazard ratio for high strain exposure (compared with low strain exposure) was 0.92 (0.46–1.84) for women and 0.75 (0.44–1.27) for men.
Conclusion — In this large prospective cohort in Canada, we observed no relationship between components of the demand-control model and incident myocardial infarction and congestive heart failure over a 15-year period.