Table 4.
Risk of breast cancer among postmenopausal women not using hormones in the Nurses' Health Study by several mammotropic hormone scoresa among 182 cases and 370 controls
| RR (95% CI)b | ||||
|---|---|---|---|---|
| Mammotropic hormone score |
Cases/controls, n | Sex hormones and prolactin | Cases/controls, n | Adding IGF-1 and c-peptide |
| Number of hormones > geometric meanc | ||||
| 0 or 1 | 20/65 | 1.0 | 8/40 | 1.0 |
| 2 or 3 | 25/90 | 0.9 (0.5 to 1.8) | 25/74 | 1.7 (0.7 to 4.1) |
| 4 or 5 | 52/99 | 1.6 (0.9 to 3.0) | 36/92 | 1.9 (0.8 to 4.5) |
| 6 or 7 | 64/87 | 2.3 (1.2 to 4.2) | 64/92 | 3.2 (1.4 to 7.3) |
| 8+ | 21/29 | 2.2 (1.0 to 4.9) | 49/72 | 3.2 (1.4 to 7.5) |
| Per 1-unit increase | 182/370 | 1.17 (1.07 to 1.26) | 182/370 | 1.15 (1.06 to 1.23) |
| Per 1 SD increasec | 182/370 | 1.44 (1.19 to 1.75) | 182/370 | 1.38 (1.16 to 1.66) |
| P trend | 182/370 | < 0.001 | 182/370 | < 0.001 |
| Score weighted by individual hormone associationsd,e | ||||
| Quintile 1 | 42/134 | 1.0 | 20/74 | 1.0 |
| Quintile 2 | 43/100 | 1.3 (0.8 to 2.2) | 27/74 | 1.3 (0.7 to 2.6) |
| Quintile 3 | 40/71 | 1.8 (1.0 to 3.0) | 35/74 | 1.7 (0.9 to 3.2) |
| Quintile 4 | 34/39 | 2.7 (1.5 to 4.8) | 44/74 | 2.2 (1.1 to 4.0) |
| Quintile 5 | 23/26 | 2.9 (1.4 to 5.6) | 56/74 | 2.7 (1.5 to 5.1) |
| Per 1 SD increased | 182/370 | 1.50 (1.24 to 1.81) | 182/370 | 1.53 (1.25 to 1.87) |
| P trend | 182/370 | < 0.001 | 182/370 | < 0.001 |
IGF-1 = insulin-like growth factor 1. aHormones included in the score are estrone, estradiol, estrone sulfate, testosterone, androstenedione, dehydroepiandrosterone, dehydroepiandrosterone sulfate and prolactin, then adding IGF-1 and c-peptide. bRR and 95% CI were adjusted for age at blood draw and menopause, parity, history of benign breast disease, family history of breast cancer, fasting status and time of day of blood draw. cScore is the number of hormones for which the participant had higher than the age- and assay batch-adjusted geometric mean hormone level. Among controls, the score with sex hormones and prolactin mean = 4.1 (SD = 2.4) and the score including IGF-1 and c-peptide mean = 5.0 (SD = 2.4). dScore is the sum of the log2-transformed hormone level multiplied by the β coefficient for that hormone with breast cancer risk. Among controls, the score with sex hormones and prolactin mean = 10.8 (SD = 1.1) and the score including IGF-1 and c-peptide mean = 12.1 (SD = 1.2). eQuintile cutpoints based on hormone score including all hormones.