Table 5

ORs and 95% CIs for incidence of breast cancer associated with estrogen-to-progesterone ratios (ng/ml)

Category meanCases (n = 194)Controls (n = 374)ORa95% CIP for trendORb95% CIP for trend
Estrone:Progesterone
 <0.0190.01513371.0Referent1.0Referent
 0.019 to <0.0600.038992071.40.70–2.71.30.67–2.7
 0.060 to <0.1010.07857921.80.86–3.71.80.84–3.7
 ≥0.1010.14925382.10.90–4.82.00.85–4.6
0.060.08
Estradiol:Progesterone
 <0.0710.06014371.0Referent1.0Referent
 0.071 to <0.1410.108991861.40.74–2.81.40.70–2.7
 0.141 to <0.2100.170561131.40.67–2.81.30.64–2.7
 ≥0.2100.26025381.90.83–4.41.70.74–4.0
0.240.33
Estriol:Progesterone
 <0.0410.03415371.0Referent1.0Referent
 0.041 to <0.0740.059781721.20.61–2.31.20.62–2.4
 0.074 to <0.1080.088821271.70.87–3.31.90.95–3.7
 ≥0.1080.12419381.30.55–2.91.40.62–3.3
0.160.07
E1 + E2 + E3:Progesteronec
 <0.1470.12513371.0Referent1.0Referent
 0.147 to <0.2730.216931921.40.70–2.81.30.64–2.6
 0.273 to <0.3990.327611071.70.82–3.61.60.76–3.3
 ≥0.3990.48927382.20.96–5.12.00.87–4.7
0.040.06
  • a OR controlling for age at index pregnancy.

  • b OR controlling for age at index pregnancy, number of previous full-term pregnancies, and age at first full-term pregnancy.

  • c E1, estrone; E2, 17β-estradiol; E3, estriol.