Table 2.

DNA adducts and lung cancer: crude estimates and conditional logistic regression models

Cases/controlsCrude OR (95% CI)Conditional OR (95% CI)
Detectable adducts102/893
Nondetectable adducts13/193
All subjects1.69 (0.93-3.08)1.86 (0.88-3.93)
    Adjusted by center2.05 (0.83-5.04)
    Never-smokers1.67 (0.69-4.01)4.04 (1.06-15.42)
    Ex-smokers1.69 (0.74-3.84)2.26 (0.78-6.53)
Age groups (y)
    <556.90 (0.91-52.1)5.56 (0.75-41.23)
    55-651.07 (0.62-1.84)2.62 (0.53-13.00)
    >651.51 (0.67-3.44)0.81 (0.14-4.47)
Above versus below median in controls (0.6 DNA adducts per 108 normal nucleotides), excluding nondetectable levels
All subjects
    Below median42/3221.00 (—)1.00 (—)
    Above median60/5710.98 (0.67-1.44)0.83 (0.49-1.41)
Never-smokers
    Below median11/1671.00 (—)1.00 (—)
    Above median34/3181.73 (0.94-3.16)2.35 (0.98-5.65)
Ex-smokers
    Below median31/1551.00 (—)1.00 (—)
    Above median26/2530.64 (0.38-1.10)0.36 (0.16-0.78)
Nondetectable adducts, below and above median (median adduct value in controls, 0.6 DNA adducts per 108 normal nucleotides)
All subjects
    Undetectable *1.00 (—)1.00 (—)
    Below median1.95 (1.01-3.70)2.51 (0.96-6.55)
    Above median1.56 (0.84-2.90)1.54 (0.58-4.07)
    DNA adducts as continuous variable1.25 (0.69-2.27)
    P for trend0.84
Never-smokers
    Undetectable1.00 (—)1.00 (—)
    Below median1.18 (0.42-3.30)4.47 (0.73-27.24)
    Above median1.92 (0.78-4.71)6.81 (1.11-41.64)
    DNA adducts as continuous variable2.17 (0.96-4.89)
    P for trend0.04
Ex-smokers
    Undetectable1.00 (—)1.00 (—)
    Below median2.43 (1.02-5.74)4.93 (1.06-22.98)
    Above median1.25 (0.52-2.97)0.80 (0.18-3.65)
    DNA adducts as continuous variable0.59 (0.27-1.33)
    P for trend0.17
  • NOTE: In addition to matching variables, estimates are adjusted for education (years of school), BMI, physical activity, and intake of fruits, vegetables, meat, and energy.

  • * Reference category. Conditional ORs adjusted as above and by center.

  • Log transformation of DNA adducts as continuous variable.