Table 5

Breast cancer risk by duration of smoking and XRCC1 Arg194Trp

Duration of smokingP for trend
Never0–2020–35≥35
194Trp noncarriers
 Case/controlsa405/584190/232165/208130/166
 Multivariate OR1b1.001.13 (0.90–1.43)1.14 (0.89–1.46)1.25 (0.96–1.64)0.08
 Multivariate OR2c1.001.17 (0.92–1.49)1.18 (0.92–1.53)1.31 (0.98–1.74)0.06
194Trp carriers
 Case/controlsa51/8323/4520/2914/22
 Multivariate OR1b0.88 (0.60–1.27)0.73 (0.43–1.24)1.13 (0.63–2.04)1.09 (0.54–2.18)0.35
 Multivariate OR2c0.88 (0.60–1.29)0.74 (0.43–1.27)1.11 (0.60–2.03)0.99 (0.48–2.00)0.40
P = 0.76 by the nominal test for interaction and 0.90 by the ordinal test in the multivariate model 2.
  • a The number of participants does not sum to total women because of missing data on genotype.

  • b Unconditional logistic regression adjusted for the matching variables: age; menopausal status; postmenopausal hormone use; date of blood draw; time of blood draw; and fasting status.

  • c Unconditional logistic regression adjusted for the matching variables, BMI at age 18 years (continuous), weight gain since age 18 years (<5, 5–19.9, ≥20 kg), age at menarche (<12, 12, 13, >13 years), age at menopause (<45, ≥45 to <50, ≥50 to <55, or ≥55 years), parity/age at first birth (nulliparous, 1–2 children/age at first birth ≤24 years, 1–2 children/age at first birth >24 years, 3+ children/age at first birth ≤24 years, 3+ children/age at first birth >24 years), first-degree family history of breast cancer (yes/no), history of benign breast disease (yes/no), alcohol intake (0, >0 to <5, ≥5 to <15, ≥15 to <30, ≥30 g/day), and duration of postmenopausal hormone use (never use, past use, current use <5 years, current use ≥5 years).