ORIGINAL ARTICLES

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

B G Armstrong¹, G Gibbs^2,3

¹ London School of Hygiene and Tropical Medicine, London, UK
² Safety Health Environmental International Consultants, Devon, Alberta, Canada
³ Department of Medicine, University of Alberta, Edmonton, Alberta, Canada

^{Correspondence to} Ben G Armstrong, London School of Hygiene and Tropical Medicine, Keppel St, London WC1E 7HT, UK; ben.armstrong{at}lshtm.ac.uk

Objectives: To estimate the exposure–response function associating polycyclic aromatic hydrocarbon (PAH) exposure and lung cancer, with consideration of smoking.

Methods: Mortality, occupational exposure and smoking histories were ascertained for a cohort of 16 431 persons (15 703 men and 728 women) who had worked in one of four aluminium smelters in Quebec from 1950 to 1999. A variety of exposure–response functions were fitted to the cohort data using generalised relative risk models.

Results: In 677 lung cancer cases there was a clear trend of increasing risk with increasing cumulative exposure to PAH measured as benzo(a)pyrene (BaP). A linear model predicted a relative risk of 1.35 (95% CI 1.22 to 1.51) at 100 µg/m^–3 BaP years, but there was a significant departure from linearity in the direction of decreasing slope with increasing exposures. Among the models tried, the best fitting were a two-knot cubic spline and a power curve (RR = (1+bx)^p), the latter predicting a relative risk of 2.68 at 100 µg/m^–3 BaP years. Additive models and multiplicative models for combining risks from occupational PAH and smoking fitted almost equally well, with a slight advantage to the additive.

Conclusion: Despite the large cohort with long follow-up, the shape of the exposure–response function and the mode of combination of risks due to occupational PAH and smoking remains uncertain. If a linear exposure–response function is assumed, the estimated slope is broadly in line with the estimate from a previous follow-up of the same cohort, and somewhat higher than the average found in a recent meta-analysis of lung cancer studies.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

Relevant Article

An improved estimate of the quantitative relationship between polycyclic hydrocarbons and lung cancer

Dario Mirabelli
Occup. Environ. Med. 2009 66: 716-717. [Extract] [Full Text] [PDF]

This article has been cited by other articles:

• Mirabelli, D. (2009). An improved estimate of the quantitative relationship between polycyclic hydrocarbons and lung cancer. Occup. Environ. Med. 66: 716-717 [Full Text]