Lung Cancer. 2005 Dec 6; [Epub ahead of print] [Link]
Ekberg-Aronsson M, Nilsson PM, Nilsson JA, Pehrsson K, Lofdahl CG.
Department of Respiratory Medicine and Allergology, University of Lund, S-221 85 Lund, Sweden.
We investigated prospectively the risk of lung cancer in relation to socio-economic status (SES) in 22 387middle-aged individuals who attended a screening program in the city of Malmo, Sweden between 1974 and 1992. We also examined the relationship between SES and histologic subtype in smokers. By 2003, a total of 550 lung cancer cases had been identified. Relative risks (RR) were calculated with adjustment for age, current smoking, inhalation habits and marital status at baseline in the low SES group compared to high SES group. Among smokers, the RR (95% confidence interval (CI)) for lung cancer in the low SES group of men was 1.39 (1.11-1.73), and women 1.56 (1.04-2.34). Also among smokers, low SES was associated with an increased risk of squamous cell carcinoma in men; RR 1.89 (1.16-2.81) and women; RR 7.10 (1.63-30.86), and with an increased risk of mesothelioma in men RR 9.97 (1.29-76.96). We conclude that low SES groups run an increased risk of lung cancer despite accounting for smoking habits. Furthermore, low SES was positively associated with squamous cell carcinoma and mesothelioma. Our results suggest that the association between low SES and lung cancer could be mediated by unaccounted for smoking exposure, lifestyle or occupational hazards.