Application of counterfactual analysis in assessing hearing loss caused by occupational noise

Objective To evaluate the applied value of counterfactual analysis in assessing hearing loss caused by occupational noise.

Methods Totally 22 690 workers exposed to occupational hazards employed in 42 enterprises distributed in 7 types of industries were considered to be the target population. Among them 14 823 noise-exposed workers were considered to be exposure group, while 1 311 workers who received pre-employment physical examination were considered to be counterfactual background. The population attributable fractions(PAF) of hearing loss caused by occupational noise were assessed.

Results The noise-exposed rate of the target population was 65.33%, the relative risk was 2.00 and the PAF was 39.51%. The PAF of elder age group over 36 years old was higher. The PAF of small-scale enterprises was higher than medium or large-scale enterprises. The PAF of metal products industry was highest, while the PAF of electronics manufacturing industry was lowest among all kinds of industries.

Conclusion Preliminary study showed that the PAF can reflect the population distribution characteristics of hearing loss. It is suggested to promote and apply counterfactual analysis to study on hearing loss caused by occupational noise.