Table 1.

Baseline characteristics^* of the sample of 11,006 Child Health and Development Studies participants at enrollment by pre-pregnancy body mass index category

Variable	Underweight BMI < 18.5	Normal weight 18.5 ≥ BMI <25.0	Overweight 25.0 ≥ BMI<30.0	Obese 30.0 ≥ BMI	P-value for difference ‡
N	983	8,379	1,258	386
BMI (kg/m2)	17.6 (0.02)	21.3 (0.02)	26.94 (0.04)	33.7 (0.19)
Age at enrollment (years)	25.2 (0.18)	26.5 (0.07)	28.4 (0.19)	29.3 (0.34)	<0.001
Age at death (years)	61.7 (0.87)	63.2 (0.38)	65.7 (0.64)	64.3 (0.89)	<0.001
Race					<0.001
White	65.7	69.8	49.4	47.4
Black	21.1	21.2	41.8	45.6
Other	13.2	9.0	8.8	6.9
Education					<0.001
< High school degree (%)	18.6	15.1	27.4	32.7
Completed high school (%)	39.4	37.2	41.2	40.8
College matriculation (%)	42.0	47.7	31.4	26.5
Annual family income ≥ $73,600 (%)§	19.2	20.4	16.6	12.2	<0.001
Age at first menstruation (years)	12.9 (0.06)	12.58 (0.02)	12.4 (0.05)	12.31 (0.09)	<0.001
Parity at enrollment (# prior pregnancies)	1.01 (0.04)	1.22 (0.02)	2.00 (0.06)	2.48 (0.12)	<0.001
Parity at study end (# total pregnancies)	1.23 (0.04)	1.50 (0.02)	2.37 (0.06)	2.86 (0.12)	<0.001
Oral Contraceptive Use (%)∥	5.2	5.0	5.0	3.1	0.32
Pre-pregnancy Hypertension (%)#	0.6	1.1	3.3	9.3	<0.001
Pre-pregnancy Diabetes (%)#	0.4	0.8	1.4	3.4	<0.001
Pre-pregnancy Kidney Disease (%)#	1.9	1.8	1.8	1.3	0.84
Smoking					0.015
Never smoker (%)	42.7	46.8	50.8	53.4
Current smoker (%)	43.0	34.6	32.2	30.2
Past smoker (%)	14.3	18.6	16.9	16.4

^*Mean (SE) or percentages

^†All data collected at enrollment in early pregnancy unless otherwise stated

^‡P-value for T-Test or Pearson Chi-Square test.

^§$73,600 in 2010 buying power. This equates to $10,000 in 1960 based on the percent increase in consumer price index from 1960 to 2010.

^∥OC use is most recent before current pregnancy

^#Hypertension, diabetes, and kidney disease are pre-pregnancy diagnosis from medical chart abstraction.