Table 3.
Interactions Between N-Acetyltransferase 2 Phenotype and Smoking History in Breast Cancer Risk, Breast and Prostate Cancer Cohort Consortium, 1989–2006
| Smoking History and NAT2 Phenotype | Cases |
Controls |
Odds Ratioa | 95% Confidence Interval | P for Interactionb | ||||
| Mean (SD) | No. | % | Mean (SD) | No. | % | ||||
| Duration of smoking (continuous), years | 0.98 | ||||||||
| Rapid + intermediate acetylators | 23.9 (13.0) | 23 (12.9) | 1.01 | 1.00, 1.01 | |||||
| Slow acetylators | 24.0 (13.2) | 23.2 (13.1) | 1.01 | 1.00, 1.01 | |||||
| Pack-years of smoking (continuous) | 0.87 | ||||||||
| Rapid + intermediate acetylators | 20.0 (18.0) | 18.7 (17.2) | 1.01 | 1.00, 1.01 | |||||
| Slow acetylators | 20.7 (19.1) | 19.0 (17.3) | 1.01 | 1.00, 1.01 | |||||
| Duration of smoking between menarche and first full-term pregnancy (continuous), years | 0.03 | ||||||||
| Rapid + intermediate acetylators | 7.4 (7.7) | 7.7 (8.1) | 1.00 | 1.00, 1.00 | |||||
| Slow acetylators | 7.4 (7.7) | 7.9 (8.6) | 1.00 | 1.00, 1.00 | |||||
| Pack-years of smoking between menarche and first full-term pregnancy (continuous) | 0.14 | ||||||||
| Rapid + intermediate acetylators | 5.4 (7.5) | 5.3 (6.9) | 1.01 | 1.00, 1.02 | |||||
| Slow acetylators | 5.5 (7.4) | 5.6 (7.5) | 1.00 | 1.00, 1.01 | |||||
| Duration of smoking (categorical), years | 0.97 | ||||||||
| Rapid + intermediate acetylators | |||||||||
| Never smoking | 1,431 | 51.7 | 2,165 | 55.4 | 1 | Reference | |||
| ≤15 | 410 | 14.8 | 559 | 14.3 | 1.14 | 0.98, 1.32 | |||
| >15 | 927 | 33.5 | 1,182 | 30.3 | 1.17 | 1.04, 1.30 | |||
| Slow acetylators | |||||||||
| Never smoking | 2,090 | 51.5 | 3,205 | 54.8 | 1 | Reference | |||
| ≤15 | 606 | 14.9 | 865 | 14.8 | 1.07 | 0.95, 1.21 | |||
| >15 | 1,362 | 33.6 | 1,775 | 30.4 | 1.18 | 1.07, 1.29 | |||
| Pack-years of smoking (categorical) | 0.87 | ||||||||
| Rapid + intermediate acetylators | |||||||||
| Never smoking | 1,431 | 52.7 | 2,163 | 56.5 | 1 | Reference | |||
| ≤20 | 772 | 28.4 | 1,045 | 27.3 | 1.13 | 1.01, 1.27 | |||
| >20 | 514 | 18.9 | 619 | 16.7 | 1.24 | 1.08, 1.42 | |||
| Slow acetylators | |||||||||
| Never smoking | 2,090 | 52.8 | 3,205 | 56.1 | 1 | Reference | |||
| ≤20 | 1,108 | 28.0 | 1,571 | 27.5 | 1.08 | 0.92, 1.19 | |||
| >20 | 757 | 19.1 | 936 | 16.4 | 1.25 | 1.11, 1.39 | |||
Abbreviations: NAT2, N-acetyltransferase 2; SD, standard deviation.
a
Logistic regression was used to estimate odds ratios and 95% confidence intervals, adjusted for age at baseline, body mass index at baseline, ever use of menopausal hormone therapy at baseline, parity, and cohort. For continuous variables, persons with no exposure comprised the reference category.
b
Interaction P values were tested using a multiplicative interaction term in the models.