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UBC Theses and Dissertations

Work-related cardiovascular risk factors among professional firefighters in British Columbia, Canada : an investigation of noise, carbon monoxide and cortisol secretion Kirkham, Tracy Lea

Abstract

Cardiovascular disease is the largest contributor to chronic disease in Canada. The evidence for the risk of cardiovascular disease among firefighters, an occupational group with known exposures to work-related cardiovascular risk factors, is inconsistent. The inconsistencies are thought to be due to influences of the healthy worker effect and lack of exposure data, limiting the ability to develop meaningful internal comparisons. This dissertation aimed to characterize exposures to work-related cardiovascular risk factors among professional firefighters in British Columbia including carbon monoxide, noise, and stress. Fifty-eight male suppression firefighters from Metro Vancouver were recruited into the exposure study from three large municipal fire departments. The first study characterized noise and carbon monoxide during firefighting. Firefighters were exposed to elevated noise levels (45% of measurements exceeded occupational limits) that may negatively contribute to their cardiovascular health. Significant determinants of noise were working dayshifts, in non-supervisory jobs, on engine and rescue trucks; responding to increasing number of emergency calls (particularly motor vehicle accidents and building alarms); conducting training; and fire equipment use. The second and third studies evaluated cortisol to determine the effects of shift work on cortisol secretion and identify determinants of exposure to stress, measured by cortisol secretion. Rotating shifts resulted in significant changes in cortisol secretion; the first day of work and mornings following nightshifts showed the greatest changes in secretion patterns. Our results suggest three days off work are required to return to baseline cortisol secretion following nightshifts. In multivariable models, work-related demographic (duration in current job, job role), psychosocial (coworker social support, subjective stress levels of events, calls involving death) and physical (wearing self-contained breathing apparatus, conducting physical training) factors were identified as determinants in changes in cortisol secretion patterns over the work day when controlling for personal factors. Collectively these studies contribute to the data gaps in the exposure measurement of work-related cardiovascular risk factors among firefighters. This dissertation provides evidence of increased exposures to cardiovascular risk factors and points to potential exposure determinants that may be used to develop internal comparisons. However; due to the variability in firefighting, further studies are needed to fully describe exposures.

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