Table 4

OR of lung cancer risk for the NQO1 C/T genotype compared with C/C using logistic regression models stratified by smoking duration in former smokersa,b

Yr of smoking5 cigarettes/day20 cigarettes/day40 cigarettes/day
OR95% CIOR95% CIOR95% CI
10.850.32–2.271.950.85–40523.911.52–10.0
100.650.28–1.501.500.80–2.802.991.42–6.28
200.480.23–1.001.110.72–1.712.221.28–3.86
300.360.17–0.730.820.59–1.161.651.05–2.58
400.260.12–0.580.610.40–0.941.220.75–1.98
500.200.08–0.500.450.24–0.850.910.48–1.71
600.150.05–0.450.340.14–0.790.670.29–1.57
700.110.03–0.410.250.08–0.750.500.17–1.47
  • a C/T is heterozygous variant, C/C is homozygous wild-type.

  • b Adjusted for age, sex, years smoked, the average number of cigarettes smoked/day, years since smoking cessation, the NQO1 genotype (with three alleles: C/C, C/T, and T/T), and the interactions between NQO1 genotype and both the number of cigarettes smoked/day and years smoked. Note that this model considers the square root of the number of cigarettes smoked/day, and years of smoking as continuous variables.