8291409 Work and heart disease: acute myocardial infarction mortality in a cohort of over two million Ontario, Canada workers

<h3>Background</h3> Despite heart disease being the second leading cause of death in Canada, the role of occupation in acute myocardial infarction (AMI) risk remains poorly understood. We examined occupational patterns in AMI mortality among workers in Ontario, Canada, and compared to previously observed AMI incidence within the same population. <h3>Methods</h3> Workers were identified through the Occupational Disease Surveillance System, linking accepted lost-time workers’ compensation claims from the Workplace Safety and Insurance Board to mortality data (2009–2021) for 2.37 million workers. Individuals aged 15 to 85 were followed to identify deaths due to AMI. Adjusted cox proportional hazard models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for AMI mortality by occupation. <h3>Results</h3> A total of 8,996 AMI-related deaths were identified. Mortality patterns mirrored some findings in incidence, with similar risks among nursing aides and orderlies (HR=1.11, 95% CI=0.93–1.32); guards and watchmen/women (HR=1.42, 95% CI=1.18–1.70); metal processing (HR=1.40, 95% CI=1.17–1.66); excavating, grading, and paving (HR=1.33, 95% CI=1.10–1.62); and truck driving (HR=1.46, 95% CI=1.35–1.57). However, some occupations showed elevated mortality risk only, such as moulding and metal casting (HR=1.48, 95% CI=1.04–2.11); clay, glass, and stone processing (HR=1.40, 95% CI=1.03–1.89); wood machining (HR=1.60, 95% CI=1.10–2.34); paper product fabricating/assembling (HR=1.59, 95% CI=1.12–2.25); railway track work (HR=2.09, 95% CI=1.28–3.41); motor transport foremen/women (HR=2.01, 95% CI=1.23-3.28) and mining foremen/women (HR=1.73, 95% CI=0.93–3.22). <h3>Conclusion</h3> Variations in AMI mortality and incidence may reflect differences in healthcare access, biological factors, occupational physical demands, and exposures such as noise, vibration, shift work, and chemical hazards. The healthy worker effect may also contribute to observed patterns.