Adjusted ORs for the association of breast cancer with selected NAT1 genotypes, cigarette smoking, and well-done meat intake among postmenopausal Iowa women
| NAT1*4/*4, *3/*4, or *3/*3 | NAT1*10/any | NAT1*11/any | |||||||
|---|---|---|---|---|---|---|---|---|---|
| No. of cases/ no. of controls | OR (95% CI)a | No. of cases/ no. of controls | OR (95% CI)a | No. of cases/ no. of controls | OR (95% CI)a | ||||
| Smoking characteristics | |||||||||
| Nonsmokers | 54/134 | 1.0 (reference) | 36/73 | 1.2 (0.7–2.0) | 5/6 | 2.1 (0.6–7.1) | |||
| Smokers | 28/63 | 1.1 (0.7–2.0) | 14/25 | 1.4 (0.7–2.9) | 5/1 | 13.2 (1.5–116.0) | |||
| Quit >10 yr ago | 12/21 | 1.3 (0.6–2.8) | 7/7 | 2.2 (0.7–6.6) | NAb | NA | |||
| 1–14 cigarettes/day or smoked <25 yr | 6/12 | 1.1 (0.4–3.1) | 2/1 | 5.0 (0.4–56.2) | NA | NA | |||
| ≥15 cigarettes/day and smoked ≥25 yr | 10/30 | 0.8 (0.3–1.6) | 5/17 | 0.6 (0.2–1.8) | NA | NA | |||
| Red meat intake (by tertile) | |||||||||
| T1 | 30/73 | 1.0 (reference) | 14/27 | 1.2 (0.6–2.6) | 2/2 | 2.7 (0.4–20.6) | |||
| T2 | 30/63 | 1.2 (0.6–2.1) | 13/36 | 0.9 (0.4–1.9) | 4/3 | 3.4 (0.7–16.2) | |||
| T3 (high) | 23/63 | 1.9 (0.5–1.7) | 24/38 | 1.6 (0.8–3.1) | 5/2 | 6.1 (1.1–33.2) | |||
| Doneness levelc | |||||||||
| Not consistently well done | 54/136 | 1.0 (reference) | 29/65 | 1.0 (0.7–1.9) | 6/4 | 3.6 (1.0–13.4) | |||
| Consistently well done | 23/40 | 1.4 (0.8–2.5) | 16/28 | 1.6 (0.7–2.7) | 2/1 | 5.6 (0.5–62.7) | |||
a Adjusted for age and family history of breast cancer. To obtain ORs from the same logistic regression model, subjects with NAT1*10/*11 genotype (two cases, no controls) were included only in the group “NAT1*11/any” in the analysis. Inclusion of these two cases in the NAT1*10/any group increased the OR from 1.4 (95% CI = 0.7–2.9) to 1.6 (95% CI = 0.8–3.3) for smokers and from 2.2 (95% CI = 0.7–6.6) to 3.3 (95% CI = 1.2–9.5) for those who had quit smoking >10 years ago.
b OR was not estimated due to the small sample size; NA, not applicable.
c Included hamburgers, beefsteak, and bacon for which information on doneness levels of meat preparation was collected.