Scandinavian Journal of Work, Environment & Health (Jan 2012)

Occupational noise exposure, social class, and risk of ischemic heart disease and all-cause mortality – a 16-year follow-up in the Copenhagen Male Study

  • Poul Suadicani,
  • Hans Ole Hein,
  • Finn Gyntelberg

DOI
https://doi.org/10.5271/sjweh.3200
Journal volume & issue
Vol. 38, no. 1
pp. 19 – 26

Abstract

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OBJECTIVE: Long-term exposure to occupational noise may be associated with an increased risk of ischemic heart disease (IHD) and all-cause mortality. However, the issue remains unsettled. Only a small number of longitudinal studies have been carried out, and control for potential confounders including a strong correlate of noise exposure namely social class may have been insufficient. METHODS: We carried out a 16-year follow-up of 2998 men aged 53–75 years without overt cardiovascular disease. RESULT: Overall, 197 men (6.6%) died due to IHD and 1192 (39.8%) from all-causes. Of the 2998 men, 1008 (33.6%) reported exposure to occupational noise for ≥5 years [mean 25.4, standard deviation (SD) 12.5 years]; among these men, 47.3% reported hearing impairment versus only 24.8% among unexposed men (63.0%). Referencing unexposed men, the hazard ratio (HR) for IHD mortality was 0.97 [95% confidence interval (95% CI) 0.71–1.33], and the HR for all-cause mortality was 1.01 (95% CI 0.89–1.15) when adjusting for potential confounders: age, hearing impairment, blood pressure, diabetes, fasting serum triglycerides and high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, glucosuria, cancer, body mass index, alcohol, tobacco, leisure-time physical activity, and social class. Stratified analyses of high and low social classes confirmed the overall results. CONCLUSION: Cumulative occupational exposure to noise was strongly associated with hearing impairment, but not with death from either IHD or all-cause mortality in a long-term follow-up adjusting for established cardiovascular risk factors including low social class.

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