Table 4.

Meta-analysis for NQO1 Pro187Ser polymorphisms and lung cancer and bladder cancer risk stratified by smoking status and lung cancer histology

No. studiesOR for variant genotype* (95% CI)Test for heterogeneity PEgger's test P
Lung cancer
    White
        Ever smokers61.08 (0.96-1.22)0.880.51
        Never smokers5§0.97 (0.62-1.54)‡‡‡0.080.90
        Adenocarcinoma60.94 (0.79-1.12)0.960.16
        Squamous cell carcinoma61.11 (0.92-1.33)0.430.04
        Small cell4**1.01 (0.74-1.38)0.290.03
    Asian
        Ever smokers††4‡‡0.78 (0.59-1.02)0.740.45
        Never smokers††4‡‡0.82 (0.60-1.12)0.790.92
        Adenocarcinoma4∥∥0.88 (0.68-1.15)0.170.37
        Squamous cell carcinoma3¶¶1.28 (0.88-1.88)0.250.70
Bladder cancer
    White
        Ever smokers***4†††1.14 (0.88-1.47)0.130.51
        Never smokers***4†††1.80 (1.18-2.76)0.220.05
  • * ORs are (C/T + T/T) vs C/C.

  • Ever smoking was defined differently in the studies: having smoked ≥100 cigarettes in lifetime (28, 38), having smoked for ≥6 months (40), having smoked at least 5 cigarettes per day (45), having smoked ≥5 cigarettes per day for at least 5 years (27), and not specifically defined (16, 26).

  • Included: refs. 16, 26, 27, 38, 40, 45.

  • § Included: refs. 16, 26, 28, 38, 40.

  • Included: 16, 26, 28, 32, 40, 45.

  • Half or more then half of the study estimates were not directly presented in the original papers; therefore, the small Egger's test P here does not necessarily suggest publication bias.

  • ** Included (26, 28, 40, 45). (32) was excluded based on the sensitivity analysis for heterogeneity.

  • †† Ever smoking was defined differently in the studies: having smoked ≥100 cigarettes in lifetime (30), having smoked at least 1 cigarette per day for 1 year (41), and not specifically defined (36, 43).

  • ‡‡ Included: refs. 30, 36, 41, 43.

  • ∥∥ Included: refs. 33, 36, 41, 43.

  • ¶¶ Included: refs. 33, 36, 43.

  • *** Ever smoking was defined differently in the studies: having smoked ≥100 cigarettes in lifetime (46, 50); and not specifically defined (48, 53).

  • ††† Included: refs. 46, 48, 50, 53.

  • ‡‡‡ Estimates derived from random effects models.