Table 5

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/*3NAT1*10/anyNAT1*11/any
No. of cases/ no. of controlsOR (95% CI)aNo. of cases/ no. of controlsOR (95% CI)aNo. of cases/ no. of controlsOR (95% CI)a
Smoking characteristics
 Nonsmokers54/1341.0 (reference)36/731.2 (0.7–2.0)5/62.1 (0.6–7.1)
 Smokers28/631.1 (0.7–2.0)14/251.4 (0.7–2.9)5/113.2 (1.5–116.0)
  Quit >10 yr ago12/211.3 (0.6–2.8)7/72.2 (0.7–6.6)NAbNA
  1–14 cigarettes/day or smoked <25 yr6/121.1 (0.4–3.1)2/15.0 (0.4–56.2)NANA
  ≥15 cigarettes/day and smoked ≥25 yr10/300.8 (0.3–1.6)5/170.6 (0.2–1.8)NANA
Red meat intake (by tertile)
 T130/731.0 (reference)14/271.2 (0.6–2.6)2/22.7 (0.4–20.6)
 T230/631.2 (0.6–2.1)13/360.9 (0.4–1.9)4/33.4 (0.7–16.2)
 T3 (high)23/631.9 (0.5–1.7)24/381.6 (0.8–3.1)5/26.1 (1.1–33.2)
Doneness levelc
 Not consistently well done54/1361.0 (reference)29/651.0 (0.7–1.9)6/43.6 (1.0–13.4)
 Consistently well done23/401.4 (0.8–2.5)16/281.6 (0.7–2.7)2/15.6 (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.