Table 2. Risk of Postmenopausal Breast Cancer per 1-SD Increase in Hormone Concentration or per 1-U Increase in Ratio of Hormone Concentrations.
| Factor | Breast cancer cases | |||
|---|---|---|---|---|
| All (n = 405) | Invasive (n = 267) | |||
| HR (95% CI)a | P value | HR (95% CI)a | P value | |
| Pregnenolone | 0.95 (0.82-1.11) | .53 | 0.96 (0.81-1.14) | .64 |
| 17-OH-pregnenolone | 1.04 (0.91-1.19) | .55 | 1.07 (0.92-1.25) | .38 |
| Progesterone | 1.16 (1.00-1.35) | .048 | 1.24 (1.07-1.43) | .004 |
| 17-OH-progesterone | 1.14 (0.99-1.31) | .06 | 1.18 (1.02-1.37) | .03 |
| 5αP | 1.06 (0.93-1.20) | .39 | 1.04 (0.90-1.20) | .60 |
| 3αHP | 1.13 (0.98-1.30) | .09 | 1.16 (0.99-1.36) | .06 |
| 20αHP | 1.07 (0.94-1.21) | .33 | 1.10 (0.96-1.26) | .17 |
| 5αP:3αHP ratio | 1.00 (0.97-1.04) | .85 | 1.00 (0.97-1.04) | .94 |
| 5αP:20αHP ratio | 0.99 (0.87-1.12) | .84 | 0.97 (0.84-1.12) | .67 |
| Progesterone:estradiol ratio | 0.98 (0.94-1.02) | .33 | 0.99 (0.95-1.04) | .75 |
Abbreviations: 20αHP, 20α-dihydroprogesterone; 3αHP, 3α-dihydroprogesterone; 5αP, 5α-dihydroprogesterone; BMI, body mass index; HR, hazard ratio.
a
Hazard ratio per 1-SD increase in individual hormone concentration or per unit increase in ratio from proportional hazard regression model with robust variance estimates and adjusted for clinic site, trial group, BMI, and duration of prior estrogen and/or progestin menopausal hormone therapy use.