Work stress, physical work demands, and device-measured physical activity: independent and joint associations with cardiovascular disease risk.

INTRODUCTION: Cardiovascular disease (CVD) is a leading cause of morbidity and mortality worldwide, and work stress is recognized as a potential contributor to increased CVD risk among workers. While meeting the moderate-to-vigorous-intensity physical activity (PA) recommendation is widely promoted for CVD prevention, evidence suggests that physical work demands may not yield the same protective effects. This study assessed work stress, physical work demands, meeting the PA recommendation, and their independent and effect modification associations with CVD risk. METHODS: Data from 5 cycles of the Canadian Health Measures Survey (2007 to 2017) were linked to CVD hospitalization and mortality records through 2019 (N = 9,860). Covariate-adjusted Cox proportional hazard models estimated independent and stratified associations between (i) self-reported work stress, (ii) physical work demands derived from occupational titles, and (iii) meeting the PA recommendation (≥150 min per week of accelerometer-measured moderate-to-vigorous intensity PA) and CVD events. RESULTS: In covariate-adjusted models, work stress was not significantly associated with CVD risk (hazard ratio [HR] for high versus low work stress = 1.08, 95% CI: 0.64 to 1.80). In stratified models, workers with low physical work demands and stationary occupations and moderate and high work stress did not have a statistically significant increased CVD risk compared with those with low stress (moderate stress: HR = 1.36, 95% CI: 0.53 to 3.44; high stress: HR = 1.34, 95% CI: 0.37 to 4.83). In contrast, among workers in high physical work demand occupations, stressful work conditions were generally associated with lower CVD risk, with substantial uncertainty around the effect estimates (moderate stress: HR = 0.41, 95% CI: 0.17 to 0.95; high stress: HR = 0.46, 95% CI: 0.06 to 3.69). Meeting the PA recommendation was also associated with lower CVD risk across levels of work stress, including among those reporting moderate or high stress; however, these associations were not statistically significant. CONCLUSION: Associations between work stress and CVD risk varied by physical work demands, with higher stress linked to greater risk in low physical work demands and stationary occupations. Meeting the PA recommendation showed a consistent trend toward lower CVD risk across levels of work stress. Overall, the findings suggest potential heterogeneity in the relationship between work stress and CVD according to physical work demands rather than demonstrating a protective effect. Further research with greater statistical power is needed to improve precision and clarify the underlying mechanisms.