Table 3.
Joint Effects of Alcohol Consumption and Smoking on Risk of Contralateral Breast Cancer
| Parameter | Controls (n = 567) |
Patients With Contralateral Breast Cancer (n = 263) |
Odds Ratio* | 95% CI | ||
|---|---|---|---|---|---|---|
| No. | % | No. | % | |||
| Alcohol consumption and smoking at first breast cancer diagnosis | ||||||
| 0-6.9 drinks/week and never/former smoker | 416 | 73.4 | 185 | 70.3 | 1.0 | Reference |
| 0-6.9 drinks/week and current smoker | 70 | 12.4 | 35 | 13.3 | 1.4 | 0.8 to 2.4 |
| ≥ 7 drinks/week and never/former smoker | 65 | 11.5 | 27 | 10.3 | 0.9 | 0.5 to 1.8 |
| ≥ 7 drinks/week and current smoker | 16 | 2.8 | 16 | 6.1 | 3.7 | 1.4 to 9.8† |
| P for interaction | .078 | |||||
| Alcohol consumption and smoking at reference date | ||||||
| 0-6.9 drinks/week and never/former smoker | 445 | 78.5 | 197 | 74.9 | 1.0 | Reference |
| 0-6.9 drinks/week and current smoker | 49 | 8.6 | 23 | 8.8 | 1.5 | 0.8 to 2.8 |
| ≥ 7 drinks/week and never/former smoker | 64 | 11.3 | 29 | 11.0 | 1.2 | 0.6 to 2.1 |
| ≥ 7 drinks/week and current smoker | 9 | 1.6 | 14 | 5.3 | 7.2 | 1.9 to 26.5† |
| P for interaction | .047 | |||||
*
Odds ratios and 95% CIs were estimated using conditional logistic regression and are implicitly adjusted for each of the matching variables (age and year of first breast cancer diagnosis, county, race/ethnicity, stage, and survival time). Risk estimates are additionally adjusted for use of adjuvant hormone therapy, chemotherapy, body mass index at reference date, and first degree family history of breast cancer.
†
P < .05.