Though tobacco smoking is the primary risk factor for lung cancer, a significant fraction of lung cancer deaths occur in lifetime non-smokers. In this paper, we calculate the burden of lung cancer in never-smokers attributable to previously identified risk factors in North America, Europe, and China, using population-based estimates of exposure prevalence and estimates of relative risk derived from recently published meta-analyses.

Population attributable fractions (PAFs) for individual risk factors ranged from 0.40% to 19.93%. Due to differences in the prevalence of exposures, the PAFs associated with several of the risk factors varied greatly by geographical region. Exposure to the selected risk factors appeared to explain a much larger proportion of lung cancer cases in never-smokers in China than in Europe and North America.

Our results demonstrate the geographic variability of the epidemiology of lung cancer in never-smokers, and highlight the need for further research in this area, particularly in Europe and North America. © 2012 Wiley-Liss, Inc.