GSTM1, smoking and lung cancer: a case-control study

Background We conducted a case-control study to examine the risk of lung ca ncer in relation to GSTM1 polymorphism and cigarette smoking (primarily of black tobacco) in a French population. Methods The 611 subjects were 301 incident lung cancer cases and 310 hospit al controls. We were able to constitute a DNA bank for 547 subjects (89.5%) and gather detailed information on smoking history for all of them. Result s presented here concern 247 cases and 254 controls. Results Taking non- or light smokers as the reference category, we estimate d odds ratios (OR) of 4.2 (95% CI: 2.6-6.7) and 5.2 (95% CI: 3.3-8.3) for t he medium and heavy smokers respectively On the other hand we estimated tha t the crude OR associating GSTM1 with lung cancer was 1.3 (95% CI: 0.9-1.8) . Furthermore our data do not depart significantly from a multiplicative mo del of the combined effects of smoking and GSTM1 deficiency. Conclusions We conclude that smoking and the GSTM1 gene are each a risk fac tor for lung cancer, and that their combined effect does not differ signifi cantly from that of a multiplicative model.