Table 1.

Characteristics of cases and controls, Nurses' Health Study and Nurses' Health Study II, mean (SD) or %

	Cases (n=539)	Controls (n=471)
Age at blood draw, y	43.9 (4.3)	43.4 (4.0)
Age at menarche, y	12.5 (1.8)	12.5 (1.4)
BMI at age 18, kg/m2	20.8 (2.6)	21.1 (2.8)
BMI at blood draw, kg/m2	24.6 (4.6)	25.2 (5.5)
Parous	82.7%	83.4%
Parity, children	2.3 (0.9)	2.4 (0.9)
Age at first birth, y	26.1 (4.7)	25.8 (4.3)
Past oral contraceptive use	82.0%	82.6%
Current oral contraceptive use	1.1%	1.1%
Family history of breast cancer	15.4%	9.3%
History of benign breast disease	28.8%	18.5%
AMH levels, pg/mL: median (10th–90th)	947 (63.2–4213)	763 (69.9–3406)