PAH exposure-associated lung cancer: An updated meta-analysis

Abstract

Background Occupational exposure to polycyclic aromatic hydrocarbons (PAHs) has been shown to be associated with lung cancer in various epidemiological studies in industries such as aluminium reduction/ smelting, coal gasification, coke production, iron/steel foundries, coal/coke and related products and carbon/graphite electrodes production. Aims To update data on the association between PAH exposure and morbidity and mortality due to lung cancer among workers in different occupations, including smoking data. Methods A comprehensive literature search was conducted to retrieve relevant papers for meta-analysis. Cohort studies with standardized mortality ratios or standardized incidence ratios and calculated overall risk ratio with their corresponding 95% confidence intervals (CIs) were included in the analysis. Chi-square test for heterogeneity was used to evaluate the consistency of findings between the studies. Results A significant risk of lung cancer was observed among the coal/coke and related product industry 1.55 (95% CI 1.01-2.37) and the iron/steel foundry industry 1.52 (95% CI 1.05-2.20). There was a wide variation in smoking habits and PAHs exposure among studies. Conclusions Coal/coke industry and iron/steel industry workers showed a higher risk of lung cancer compared with other occupations exposed to PAHs. The confounding effects of smoking and individual exposure levels of PAH should be taken into account.