Exposure to occupational noise and cardiovascular disease in the United States: the National Health and Nutrition Examination Survey 1999-2004.

BACKGROUND Chronic exposure to occupational noise may be associated with increased risk of coronary heart disease (CHD) and hypertension. However, findings are inconsistent and many previous studies are limited by small sample size and inappropriate control for potential confounders. We used a nationally representative US sample to examine associations of self-reported exposure to occupational noise with CHD and hypertension. METHODS This cross-sectional study included 6307 participants of the National Health and Nutrition Examination Survey 1999-2004, aged ≥ 20 years and employed at the time of interview. Noise exposure assessment was based on self-reported exposure to loud noise in the workplace. RESULTS Compared with never exposed participants, subjects chronically exposed to occupational noise had a 2-3-fold increased prevalence of angina pectoris, myocardial infarction, CHD and isolated diastolic hypertension. After adjustment for various covariates, the odds ratios (95% CIs) for angina pectoris, CHD and isolated diastolic hypertension were 2.91 (1.35 to 6.26), 2.04 (1.16 to 3.58) and 2.23 (1.21 to 4.12), respectively. There were clear exposure-response relationships for the observed associations. Associations of noise exposure with angina pectoris, myocardial infarction and CHD were particularly strong for participants aged < 50 years, men and current smokers. There was no significant increase in levels of cardiovascular biomarkers including blood lipids and circulating inflammatory mediators associated with noise exposure. CONCLUSIONS Chronic exposure to occupational noise is strongly associated with prevalence of CHD, especially for young male current smokers. This study suggests that excess noise exposure in the workplace is an important occupational health issue and deserves special attention.