Supplementary Table 1. Odds ratios of reproductive factors for ER/PR breast cancer subtypes by menopausal status, Seoul Breast Cancer Study

Premenopausal / Postmenopausal
Overall / ER/PR(+)f / ER/PR(-)f / pb / Overall / ER/PR(+)f / ER/PR(-)f / pb
(N=3,637) / (N=1,428) / (N=483) / (N=3,222) / (N=857) / (N=412)
ORa / 95% CI / ORa / 95% CI / ORa / 95% CI / ORa / 95% CI / ORa / 95% CI / ORa / 95% CI
Menarche age per year / 0.94 / 0.90-0.98 / 0.95 / 0.90-0.99 / 0.91 / 0.85-0.98 / 0.299 / 0.93 / 0.90-0.97 / 0.92 / 0.87-0.96 / 0.96 / 0.91-1.03 / 0.154
Ever pregnancy / 0.40 / 0.21-0.73 / 0.30 / 0.15-0.58 / 1.52 / 0.87-4.05 / 0.001 / 0.31 / 0.16-0.60 / 0.18 / 0.09-0.39 / 1.24 / 0.41-3.71 / 0.001
Age at FFTPc, per year / 1.03 / 1.01-1.05 / 1.04 / 1.01-1.06 / 0.99 / 0.96-1.02 / 0.009 / 1.03 / 1.00-1.05 / 1.04 / 1.01-1.07 / 1.00 / 0.97-1.03 / 0.023
No. of children / 1.01 / 0.90-1.13 / 1.03 / 0.91-1.16 / 1.00 / 0.84-1.19 / 0.755 / 1.03 / 0.95-1.12 / 1.01 / 0.92-1.11 / 1.07 / 0.94-1.21 / 0.410
Duration of EEBF (years)d per year / 1.03 / 1.02-1.05 / 1.04 / 1.02-1.06 / 1.02 / 0.99-1.04 / 0.119 / 1.03 / 1.02-1.05 / 1.05 / 1.03-1.07 / 1.00 / 0.98-1.03 / 0.003
Never breast feeding / 1.09 / 0.92-1.29 / 1.12 / 0.91-1.37 / 1.06 / 0.77-1.45 / 0.746 / 1.12 / 0.89-1.40 / 1.19 / 0.87-1.62 / 1.04 / 0.70-1.55 / 0.577
Breast feeding duration per month / 1.00e / 1.00-1.01 / 1.00 / 0.99-1.01 / 1.00 / 0.99-1.01 / 0.925 / 1.01 / 1.00-1.01 / 1.00e / 1.00-1.01 / 1.01 / 1.00-1.01 / 0.393

aORs analyzed by logistic regression adjusting for age(cont'), family history, ever pregnancy, age at FFTP and age at menarche

bp for heterogeneity between ER/PR status
cFFTP: first full term pregnancy

dEEBF: estrogen exposure before first full term pregnancy

eP0.05

f ER/PR(+), either ER+ and/or PR+; ER/PR(-), both ER- and PR -