Exposure-response relationship between lung cancer and polycyclic aromatic hydrocarbons (PAHs)

Area of Science:

• Occupational Health
• Environmental Epidemiology
• Toxicology

Background:

• Aluminum smelter workers face occupational exposure to polycyclic aromatic hydrocarbons (PAHs).
• Understanding the dose-response relationship between PAH exposure and lung cancer is crucial for risk assessment.
• Smoking is a significant confounder in lung cancer studies.

Purpose of the Study:

• To estimate the exposure-response function between polycyclic aromatic hydrocarbon (PAH) exposure and lung cancer.
• To account for the influence of smoking on lung cancer risk in this cohort.
• To compare different models for describing the PAH-lung cancer relationship.

Main Methods:

• A cohort of 16,431 aluminum smelter workers in Quebec was studied from 1950 to 1999.
• Occupational exposure to PAHs, primarily measured as benzo(a)pyrene (BaP), was assessed.
• Generalized relative risk models were used to fit various exposure-response functions.

Main Results:

• A clear trend of increased lung cancer risk with cumulative PAH exposure was observed.
• A linear model estimated a relative risk of 1.35 at 100 microg/m(-3) BaP-years, but non-linear models provided a better fit.
• The best fitting models, a cubic spline and a power curve, predicted higher risks at elevated exposures.

Conclusions:

• The precise shape of the PAH exposure-response curve and its interaction with smoking remain uncertain.
• Assuming a linear model, the estimated risk aligns with previous findings for this cohort but is higher than meta-analysis averages.
• Further research is needed to clarify the exposure-response function and risk combination models.