PGR and breast cancer: Young-adult BMI was associated with reduced risk of postmenopausal BC, with similar results for BC overall (>23.7 vs. ≤21.2 kg/m2: OR = 0.68, 95% CI:0.54-0.86, Ptrend < 0.01) and ER+PR+ BC (>23.7 vs. ≤21.2 kg/m2: OR = 0.73, 95% CI:0.54-0.98, Ptrend = 0.04).