Table 8.
Odds ratios (ORs) for breast cancer according to cigarette smoking and the CYP1A1 genotype at the M1 locus, according to menopausal status (African-American and white women combined), additive scale and interaction contrast ratios
| Genotype | Overall | Premenopausal | Postmenopausal | |||||||
| Cases/controls | OR (95% CI)a | ICR (95% CI) | Cases/controls | OR (95% CI)a | ICR (95% CI) | Cases/controls | OR (95% CI)a | ICR (95% CI) | ||
| Active smoking status | ||||||||||
| Never | wt/wtb | 252/256 | Reference | 132/120 | Reference | 120/136 | Reference | |||
| Never | M1 variantc | 96/115 | 0.8 (0.6–1.2) | 46/47 | 0.9 (0.5–1.4) | 50/68 | 0.8 (0.5–1.3) | |||
| Former | wt/wt | 143/129 | 1.2 (0.9–1.6) | 62/53 | 1.0 (0.7–1.6) | 81/76 | 1.3 (0.9–1.9) | |||
| Former | M1 variant | 65/47 | 1.4 (0.9–2.2) | +0.4 (-0.2, 1.1) | 37/26 | 1.3 (0.7–2.2) | +0.4 (-0.5, 1.2) | 28/21 | 1.5 (0.8–2.9) | +0.5 (-0.5, 1.5) |
| Current | wt/wt | 87/105 | 0.8 (0.6–1.2) | 48/48 | 0.9 (0.5–1.4) | 39/57 | 0.8 (0.5–1.3) | |||
| Current | M1 variant | 35/43 | 0.9 (0.5–1.4) | 20/25 | 0.7 (0.4–1.4) | 15/18 | 1.0 (0.5–2.1) | |||
| Number of cigarettes (pack/day) | ||||||||||
| Never | wt/wtb | 252/256 | Reference | 132/120 | Reference | 120/136 | Reference | |||
| Never | M1 variantc | 96/115 | 0.8 (0.6–1.2) | 46/47 | 0.9 (0.5–1.4) | 50/68 | 0.8 (0.5–1.3) | |||
| ≤ 1 | wt/wt | 159/159 | 1.0 (0.8–1.4) | 76/70 | 1.0 (0.6–1.4) | 83/89 | 1.1 (0.7–1.6) | |||
| ≤ 1 | M1 variant | 71/64 | 1.2 (0.8–1.7) | 43/38 | 1.0 (0.6–1.7) | 28/26 | 1.3 (0.7–2.3) | |||
| > 1 | wt/wt | 68/74 | 1.0 (0.7–1.4) | 32/30 | 0.9 (0.5–1.6) | 36/44 | 1.0 (0.6–1.7) | |||
| > 1 | M1 variant | 29/26 | 1.2 (0.7–2.1) | +0.4 (-0.4, 1.1) | 14/13 | 1.0 (0.4–2.2) | +0.1 (-0.9, 1.1) | 15/13 | 1.4 (0.6–3.0) | +0.6 (-0.6, 1.7) |
| Duration of smoking | ||||||||||
| Never | wt/wtb | 252/256 | Reference | 132/120 | Reference | 120/136 | Reference | |||
| Never | M1 variantc | 96/115 | 0.8 (0.6–1.2) | 46/47 | 0.9 (0.5–1.4) | 50/68 | 0.8 (0.5–1.3) | |||
| ≤ 20 years | wt/wt | 119/127 | 0.9 (0.7–1.2) | 80/77 | 0.9 (0.6–1.3) | 39/50 | 0.9 (0.6–1.5) | |||
| ≤ 20 years | M1 variant | 51/57 | 0.9 (0.6–1.3) | 37/39 | 0.8 (0.5–1.4) | 14/18 | 0.9 (0.4–1.7) | |||
| > 20 years | wt/wt | 110/106 | 1.2 (0.9–1.6) | 30/23 | 1.2 (0.7–2.2) | 80/83 | 1.2 (0.8–1.7) | |||
| > 20 years | M1 variant | 49/33 | 1.7 (1.1–2.8) | +0.7 (-0.2, 1.6) | 20/12 | 1.5 (0.7–3.3) | +0.5 (-0.7, 3.8) | 29/21 | 1.7 (0.9–3.1) | +0.7 (-1.4, 5.3) |
| Time since cessation | ||||||||||
| Never | wt/wtb | 252/256 | Reference | 132/120 | Reference | 120/136 | Reference | |||
| Never | M1 variantc | 96/115 | 0.8 (0.6–1.2) | 46/47 | 0.9 (0.5–1.4) | 50/68 | 0.8 (0.5–1.3) | |||
| < 10 years | wt/wt | 76/53 | 1.5 (1.0–2.2) | 33/24 | 1.1 (0.6–2.0) | 43/29 | 1.8 (1.0–3.0) | |||
| < 10 years | M1 variant | 41/14 | 3.0 (1.6–5.7) | +1.7 (-0.7, 3.8) | 23/8 | 2.4 (1.0–5.7) | +1.6 (-0.7, 3.8) | 18/6 | 3.6 (1.4–9.4) | +2.0 (-1.4, 5.3) |
| ≥ 10 years | wt/wt | 67/76 | 1.0 (0.7–1.5) | 29/29 | 0.9 (0.5–1.7) | 38/47 | 1.0 (0.6–1.6) | |||
| ≥ 10 years | M1 variant | 24/33 | 0.8 (0.4–1.3) | 14/18 | 0.7(0.3–1.5) | 10/15 | 0.7 (0.3–1.7) | |||
| Age started smoking | ||||||||||
| Never | wt/wtb | 252/256 | Reference | 132/120 | Reference | 120/136 | Reference | |||
| Never | M1 variantc | 96/115 | 0.8 (0.6–1.2) | 46/47 | 0.9 (0.5–1.4) | 50/68 | 0.8 (0.5–1.3) | |||
| < 18 years | wt/wt | 87/84 | 1.0 (0.7–1.5) | 45/44 | 0.8 (0.5–1.4) | 42/40 | 1.3 (0.8–2.1) | |||
| < 18 years | M1 variant | 35/25 | 1.4 (0.8–2.4) | +0.5 (-0.3, 1.4) | 24/12 | 1.6 (0.8–3.4) | +0.9 (-0.4, 2.2) | 11/13 | 1.0 (0.4–2.4) | -0.1 (-1.1, 1.0) |
| ≥ 18 years | wt/wt | 143/150 | 1.0 (0.8–14) | 65/57 | 1.0 (0.7–1.6) | 78/93 | 1.0 (0.7–1.5) | |||
| ≥ 18 years | M1 variant | 65/65 | 1.1 (0.7–1.6) | 33/39 | 0.8 (0.5–1.4) | 32/26 | 1.4 (0.8–2.6) | |||
CI, confidence interval. a Adjusted for age, race, and sampling fractions. b wt = wild-type homozygote genotype. c M1 variant = M1/M1 or M1/wt genotypes.