PGR and breast cancer: BMI was associated strongly positively with breast cancer overall (HR = 1.074; 1.049–1.098), for post-menopausal women (HR = 1.117; 1.085–1.150), for cancers diagnosed at age ≥ 55 years (HR = 1.104; 1.076–1.132), and for ER + PR + subtypes (HR = 1.122; 1.080–1.165; n = 3101), but not for PR- subtypes.