Relationship between cumulative exposure to occupational lifting throughout working life and risk of ischemic heart disease in men and women. The Copenhagen Aging and Midlife Biobank.

Abstract

Ischemic heart disease (IHD) causes mortality and morbidity. High levels of occupational physical activity (OPA) increases IHD risk, and occupational lifting (OL) is suggested as a detrimental OPA exposure. This study investigated the association between accumulated OL throughout working life, and risk for IHD, and potential sex and hypertension differences. Data from Copenhagen Ageing and Midlife Biobank linked to register-based information on incident IHD during 9 years follow-up in the Danish National Patient Registry were included. The outcome was the odds of IHD from baseline (2009-2011) to end of follow-up (2018), among participants without IHD at baseline. Accumulated OL was assessed by linking occupational codes to a Job Exposure Matrix, creating a measure in ton-years (lifting 1,000 kg/day/year). Multivariable logistic regression tested associations between level of accumulated OL and IHD, among the 6,606 included individuals (68% men). During follow-up, 7.3% men and 3.6% women were hospitalized with IHD. Among all participants, the odds for IHD were 47% (OR 1.47, 95% CI 1.05-2.06) higher among those with ≥5 to <10 ton-years, 39% (OR 1.39, 95% CI 1.06-1.83) higher among those with ≥10 to <30 ton-years, and 62% (OR 1.62, 95% CI 1.18-2.22) higher among those with ≥30 ton-years, compared to no accumulated OL. However, these increased odds were in the same direction in the fully-adjusted model but statistically insignificant, ≥5 to <10 ton-years OR 1.28, 95% CI 0.88-1.88; ≥10 to <30 ton-years OR 1.20, 95% CI 0.85-1.69; and ≥30 ton-years OR 1.22, 95% CI 0.81-1.84. No statistically significant interactions, nor any associations, between OL and sex, or hypertension were seen.