Overview

Abstract (English)

Occupational noise exposure is associated with an increased risk of cardiovascular disease. A biological model explains this association through a general stress reaction and the dysregulation of otherwise normal psychoneuralhormonal pathways. Given this evidence and the hypothesized link between stress and metabolic disorders or immunologic response (i.e. inflammation) we hypothesized that risk of diabetes and arthritis are elevated in those exposed to noise at work. Cases and controls were drawn from the National Population Health Survey (NPHS), a longitudinal survey conducted by Statistics Canada. Eligible subjects were aged 18 to 55 in the first cycle (1994/1995) and who did not have the health outcome of interest up to and including the fourth cycle (2000/2001). Cases were determined from self reports in the fifth (2002/2003) through eighth cycle (2008/2009); each case was matched to five controls who were disease free at the time when the case was diagnosed. Subjects’ noise exposure at work was assessed using cumulative exposure. Noise levels by various occupations/industries were derived from a job exposure matrix built from WorkSafeBC’s noise exposure dataset and exposure duration was estimated according to the self-reported work status in the NPHS. Conditional logistic regression was used to estimate the odds ratios of developing the health outcomes of interest; models were adjusted for life style factors (physical activity, smoking, drinking), socio-economic factors (education, family income), and health status factors (hypertension, obesity). In the current study the adjusted diabetes ORs (95% CI) for medium and high exposure groups (using low exposure group as reference) were 0.93 (0.61 – 1.41) and 1.04 (0.67 – 1.59), respectively. The corresponding ORs (95% CI) for rheumatoid arthritis were 1.01 (0.56 – 1.82) and 1.07 (0.57 – 2.01). For cardiovascular disease, the ORs (95% CI) were 0.87 (0.59 – 1.28) and 0.85 (0.57 – 1.27). We did not find evidence of an increased risk of diabetes, rheumatoid arthritis, or cardiovascular disease in those exposed to occupational noise. Possible biases in this study may explain the lack of an observed association including misclassification bias – particularly of exposure – and the healthy worker effect. Future studies are warranted and should focus on improving exposure assessment.

Abstract (French)

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