Table 1.

Characteristics of 884 mother-infant pairs in Project Viva according to infant feeding method during 6 months after birth

		N	%	Breastfeeding (bf) dose/duration during 6 months (%)				P for trend
				Never breastfed N=81 (9%)	Any bf <6 months N=341 (39%)	Any bf for 6 months N=241 (27%)	Full bf for 6 months N=221 (25%)
Maternal characteristics
Age at enrollment (years)	<25	56	6	9	11	4	1	0.001
	25–35	550	62	63	60	63	64
	≥35	278	31	28	29	33	35
Educational level	High school or less	52	6	10	8	5	2	<0.0001
	Some college	177	20	40	25	13	12
	BA/BS	328	37	35	40	37	33
	Graduate school	327	37	16	26	45	52
Race /ethnicity	Black	89	10	7	13	10	6	0.02
	Hispanic	46	5	5	6	7	2
	Other	77	9	2	11	8	9
	White	672	76	85	69	76	83
Smoking during pregnancy	Smoker	82	9	14	15	6	3	0.04
	Former smoker	180	20	23	19	23	19
	Never	622	70	63	66	71	68
Prepregnancy BMI, kg/m2	< 25	580	66	51	62	71	71	<0.0001
	25–30	195	22	31	23	18	22
	≥ 30	109	12	19	16	11	6
Excessive pregnancy weight gain ( 2009 Institute of Medicine category)		527	60	65	60	59	57	0.22
Child characteristics
Male		442	50	49	50	51	50	0.83
Birth weight-for-gestational age z score, mean (SD)		0.25 (0.93)		0.20 (0.95)	0.20 (0.93)	0.21 (0.93)	0.38 (0.91)	0.04
Change in weight-for-age z score between birth and 6 months, mean (SD)		0.24 (1.09)		0.43 (0.94)	0.49 (1.03)	0.05 (1.16)	−0.03 (1.07)	<0.0001
Age 3 anthropometric characteristics
BMI z score, mean (SD)		0.45 (1.03)		0.58 (1.19)	0.61(1.01)	0.28 (1.10)	0.33 (0.86)	0.0003
BMI categories IOTF	normal	749	85	83	81	85	91	0.0008
	overweight	105	12	11	13	13	9 1
	obese	30	3	6	5	2	91
BMI percentiles	< 5th	20	2	2	1	4	2	<0.0001
	5th–85th	632	71	63	69	74	76
	85th–95th	151	17	21	18	12	19
	≥ 95th	81	9	14	12	10	2
Skinfold thicknesses (mm, mean (SD))   Sum of subscapular and triceps		16.7 (4.0)		17.8 (4.5)	17.2 (4.2)	16.1 (3.9)	16.1 (3.5)	<0.0001

BMI = Body Mass Index