Table 1b. Age and age-standardized baseline characteristics according to childhood somatotype among participants in the Nurses’ Health Study (N=76,299) and Nurses’ Health Study II (N=112,390).

	NHS (1988)			NHS II (1989)
	1 (leanest) (n=23208)	3 (n=14643)	≥5 (heaviest) (n=5387)	1 (leanest) (n=19691)	3 (n=28052)	≥5 (heaviest) (n=7144)
Mean (SD)
Age*	55.3 (6.9)	53.7 (7.2)	53.7 (7.1)	34.3 (4.8)	33.8 (4.6)	34.5 (4.6)
Height	64.5(2.5)	64.5 (2.4)	64.6 (2.5)	64.9 (2.7)	64.8 (2.6)	65.1 (2.6)
Age at first birth (years)**	25.1 (3.3)	25.1 (3.2)	25.2 (3.3)	25.3 (4.0)	25.5 (4.0)	25.4 (4.1)
Parity	3.5 (5.6)	3.4 (5.2)	3.3 (5.0)	2.1 (0.9)	2.1 (0.9)	2.0 (0.9)
Alcohol intake (g/day)	6.1 (10.5)	6.2 (10.7)	6.1 (11.0)	3.1 (5.8)	3.0 (5.6)	3.1 (6.2)
BMI at age 18 (kg/m2)	19.8 (2.2)	21.9 (2.6)	24.6 (3.9)	19.4 (2.1)	21.5 (2.8)	24.8 (4.7)
Current BMI (kg/m2)	24.5 (4.0)	26.0 (4.8)	27.6 (5.6)	24.2 (4.7)	24.1 (4.7)	23.9 (4.8)
Weight change since age 18, kg	12.5 (10.5)	11.1 (12.0)	9.1 (15.0)	7.4 (8.2)	7.9 (10.8)	7.6 (15.3)
Age at menarche (years)	12.8 (1.4)	12.4 (1.4)	12.2 (1.4)	12.8 (1.5)	12.3 (1.4)	12.0 (1.5)
Percentage
History of benign breast disease	17	15	14	10	8	6
Irregular menstrual cycles ages 18-22	24	22	25	24	23	26
Current hormone therapy use^	32	31	28	87	81	77
Former smoker	35	38	40	20	22	23
Current smoker	18	18	24	13	13	20
Birth weight ≥ 8.5 lbs	7	11	16	8	11	15
Parous	94	94	93	71	72	63
Premenopausal	29	30	30	97	97	96
Ever oral contraceptive use	50	50	49	85	83	81
Family history of breast cancer	11	10	10	6	6	6

Note: Values are means (SD) or percentages and are standardized to the age distribution of the study population.

^aValue is not age adjusted

^bamong parous women

^camong postmenopausal women