Table 3.
Odds ratios (ORs) and confidence intervals (CIs) of breast Cancer by prediagnostic serum estradiol concentration stratified by menstrual-cycle phase a
| Hormone | Number of cases/number of controls | Unadjusted | Adjusted | ||||
|---|---|---|---|---|---|---|---|
| OR | (95% CI) | P b | OR | (95% CI) | P b | ||
| All participants | |||||||
| Estradiol | 0.62 | 0.48 | |||||
| 5-54 pg/ml | 22/45 | 1.0 | 1.0 | ||||
| 55-94 pg/ml | 28/37 | 1.7 | (0.8 to 3.6) | 1.9 | (0.8 to 4.6) | ||
| 95-138 pg/ml | 24/43 | 1.2 | (0.6 to 2.5) | 1.1 | (0.5 to 2.5) | ||
| 139-497 pg/ml | 24/43 | 1.1 | (0.5 to 2.2) | 1.4 | (0.6 to 3.4) | ||
| Bioavailable estradiol | 0.46 | 0.38 | |||||
| 1.5-31.3 pg/ml | 23/43 | 1.0 | 1.0 | ||||
| 31.6-54.9 pg/ml | 25/42 | 1.2 | (0.6 to 2.5) | 1.2 | (0.5 to 2.8) | ||
| 55.0-79.2 pg/ml | 26/41 | 1.2 | (0.6 to 2.6) | 1.2 | (0.5 to 2.8) | ||
| 79.3-302.4 pg/ml | 24/42 | 1.1 | (0.5 to 2.2) | 1.3 | (0.5 to 3.1) | ||
| Follicularc | |||||||
| Estradiol | 0.52 | 0.69 | |||||
| 5-54 pg/ml | 10/22 | 1.0 | 1.0 | ||||
| 56-108 pg/ml | 13/21 | 1.5 | (0.5 to 4.3) | 2.4 | (0.6 to 10.6) | ||
| 110-480 pg/ml | 12/21 | 1.4 | (0.4 to 4.2) | 1.4 | (0.3 to 6.5) | ||
| Bioavailable estradiol | 0.51 | 0.70 | |||||
| 1.5-31.7 pg/ml | 12/21 | 1.0 | 1.0 | ||||
| 32.2-62.9 pg/ml | 8/25 | 0.6 | (0.2 to 1.9) | 0.7 | (0.1 to 3.1) | ||
| 63.5-264.2 pg/ml | 15/18 | 1.8 | (0.6 to 5.8) | 2.0 | (0.5 to 8.3) | ||
| Luteald | |||||||
| Estradiol | 0.49 | 0.62 | |||||
| 6-78 pg/ml | 10/24 | 1.0 | 1.0 | ||||
| 80-114 pg/ml | 16/18 | 2.0 | (0.7 to 5.8) | 2.3 | (0.6 to 9.2) | ||
| 115-299 pg/ml | 11/23 | 1.2 | (0.4 to 3.2) | 1.3 | (0.4 to 4.3) | ||
| Bioavailable estradiol |
0.29 | 0.51 | |||||
| 3.5-48.4 pg/ml | 9/25 | 1.0 | 1.0 | ||||
| 48.8-67.9 pg/ml | 15/19 | 2.1 | (0.7 to 6.0) | 2.5 | (0.6 to 10.5) | ||
| 68.2-184.6 pg/ml | 13/21 | 1.6 | (0.6 to 4.4) | 1.8 | (0.6 to 5.8) | ||
aCases and controls were matched on age, date, hour, and days since last menses at blood collection. All adjusted models include terms for age and menstrual-cycle day at blood collection, height, BMI, age at menarche, number of term pregnancies, smoking status, and history of breast cancer in first-degree relative. Hormone cut points define quartiles or menstrual-cycle phase-specific tertiles estimated from all participants. bP values (two-sided) were calculated by using conditional logistic regression, with log-transformed hormone concentrations entered as a linear term to test for trend by using a Wald test. cThe case and matched controls were in the follicular phase of the menstrual cycle at blood collection (0 to 13 days since last menses). dThe case and matched controls were in the luteal phase of the menstrual cycle at blood collection (14 to 33 days since last menses).