Table 5.

Doubling of circulating endogenous hormones and breast cancer risk, by time between first birth and diagnosis: FMC (n = 3,480)

Years between first birth and diagnosis
<10 years≥10 years
Cases/controlsOR (95% CI)Cases/controlsOR (95% CI)Pheta
Estradiol
 Overall514/9841.00 (0.85–1.17)678/1,2771.02 (0.88–1.17)0.89
 ER+/PR+173/3260.87 (0.66–1.16)261/4871.01 (0.80–1.27)0.43
 ER/PR83/1611.32 (0.87–2.00)79/1501.07 (0.72–1.59)0.47
Estrone
 Overall514/9851.03 (0.91–1.16)678/1,2771.00 (0.90–1.11)0.72
 ER+/PR+173/3271.00 (0.82–1.23)261/4870.98 (0.82–1.16)0.84
 ER/PR83/1611.13 (0.84–1.52)79/1501.02 (0.75–1.40)0.66
Progesterone
 Overall514/9860.98 (0.79–1.21)678/1,2761.21 (1.00–1.46)0.15
 ER+/PR+173/3270.88 (0.60–1.27)261/4860.97 (0.70–1.34)0.69
 ER/PR83/1611.91 (0.99–3.70)79/1501.04 (0.59–1.82)0.17
Testosterone
 Overall514/9861.06 (0.91–1.24)676/1,2741.13 (0.97–1.30)0.58
 ER+/PR+173/3271.11 (0.85–1.44)260/4861.07 (0.84–1.35)0.84
 ER/PR83/1611.47 (0.95–2.27)79/1500.98 (0.66–1.46)0.18

NOTE: Conditional logistic regression models adjusted for gestational age at blood donation and family history of breast cancer.

  • aPhet between <10 and ≥10 years between first pregnancy and diagnosis.