Table 3.
Breast cancer risk and risk factors by CYP17 genotype (BRCA1 and BRCA2 mutation carriers excluded)
| Factor | All data | A1/A1 | A1/A2 and A2/A2 | ||||||
| Case, n (%) | Control, n (%) | OR (95% CI) | Case, n (%) | Control, n (%) | OR (95% CI) | Case, n (%) | Control, n (%) | OR (95% CI) | |
| Premenopausal | |||||||||
| Age at menarche | |||||||||
| <13 years | 435 (42) | 207 (39) | 1.00 | 183 (45) | 95 (47) | 1.00 | 252 (40) | 112 (34) | 1.00 |
| ≥13 years | 603 (58) | 321 (61) | 0.93 (0.7–1.2) | 228 (55) | 105 (53) | 1.18 (0.8–1.8) | 375 (60) | 216 (66) | 0.79 (0.6–1.1) |
| Age at first birth | |||||||||
| <25 years | 318 (40) | 145 (39) | 1.00 | 131 (42) | 52 (37) | 1.00 | 187 (39) | 93 (40) | 1.00 |
| ≥25 years | 479 (60) | 231 (61) | 1.13 (0.9–1.5) | 183 (58) | 89 (63) | 0.93 (0.6–1.5) | 296 (61) | 142 (60) | 1.30 (0.9–1.8) |
| Ever use OC | |||||||||
| No | 87 (8) | 32 (6) | 1.00 | 32 (8) | 12 (6) | 1.00 | 55 (9) | 20 (6) | 1.00 |
| Yes | 955 (92) | 497 (94) | 0.82 (0.5–1.4) | 382 (92) | 189 (94) | 0.75 (0.3–1.9) | 573 (91) | 308 (94) | 0.82 (0.4–1.7) |
| Postmenopausal | |||||||||
| Age at menarche | |||||||||
| <13 years | 101 (42) | 63 (42) | 1.00 | 44 (44) | 28 (42) | 1.00 | 57 (40) | 35 (42) | 1.00 |
| ≥13 years | 140 (58) | 87 (58) | 0.92 (0.6–1.5) | 55 (55) | 38 (58) | 0.83 (0.4–1.9) | 85 (60) | 49 (58) | 0.84 (0.4–1.7) |
| Age at first birth | |||||||||
| <25 years | 122 (60) | 77 (57) | 1.00 | 47 (57) | 37 (61) | 1.00 | 75 (62) | 40 (54) | 1.00 |
| ≥25 years | 79 (40) | 58 (43) | 0.98 (0.6–1.6) | 35 (43) | 24 (39) | 1.16 (0.5–2.7) | 44 (38) | 34 (46) | 0.84 (0.4–1.7) |
| Ever use HRT | |||||||||
| No | 79 (33) | 61 (41) | 1.00 | 31 (31) | 28 (42) | 1.00 | 45 (32) | 33 (39) | 1.00 |
| Yes | 165 (67) | 89 (59) | 1.86 (1.1–3.1)1 | 68 (69) | 38 (58) | 2.40 (1.0–5.7)2 | 97 (68) | 51 (61) | 1.93 (0.9–4.0)3 |
| Age at menopause | |||||||||
| <48 years | 136 (56) | 85 (57) | 1.00 | 50 (51) | 40 (61) | 1.00 | 83 (58) | 45 (37) | 1.00 |
| ≥48 years | 107 (44) | 65 (43) | 1.25 (0.7–2.2) | 48 (49) | 26 (39) | 2.59 (1.0–7.0)4 | 59 (42) | 39 (63) | 0.80 (0.4–1.7) |
Adjusted odds ratios (ORs) for premenopausal women are adjusted for age at menarche, age at first birth, ever use of OC, reference age, body mass index, family history defined by any first-degree relative who had breast cancer, state, education level, country of birth and benign breast lump disease. The same adjustment was performed for postmenopausal women except for ever use of hormone replacement therapy (HRT) instead of ever use of OC; adjustment was also made for age at menopause. 1P = 0.02, 2P = 0.05, 3P = 0.08, 4P = 0.06.