The Joint Effect of Industrial Noise Exposure and Job Complexity on All-Cause Mortality - The CORDIS Study.

In a previous follow-up study of industrial workers (the CORDIS study, Melamed et al., 1999a) we demonstrated a dose-response relationship between occupational noise exposure levels and all-cause mortality. In that study the type of jobs that workers were engaged in was not taken into account. However, in further analyses of CORDIS data we have found that noise exposure is particularly detrimental to health for workers engaged in complex jobs. Therefore in this 12-year study we attempted to determine the combined effect of job complexity and noise exposure on all-cause mortality in 2606 industrial workers. We divided the workers into four groups based on a combination of either high or low noise exposure, and whether they performed simple or complex jobs. There was an increased risk for all-cause mortality (OR = 1.86, 95% CI = 1.04-3.32), in workers who performed complex jobs under high noise exposure levels compared to those who performed simple jobs under low noise exposure. This remained significant even after adjusting for possible confounding variables. There was a trend for a more pronounced effect among less educated workers, among blue-collar workers, and in those with higher tenure. We conclude that occupational noise exposure is associated with excess mortality risk among workers performing complex jobs.