TABLE 1.
Characteristics of 847 Project Viva Mother-Child Dyads According to Timing of Solid Food Introduction and Breastfeeding Status at 4 Months of Age
| Overall (n = 847) | Breastfed Age at Introduction of Solids, mo |
P | Formula-Fed Age at Introduction of Solids, mo |
P | |||||
|---|---|---|---|---|---|---|---|---|---|
| <4 (n = 43) | 4–5 (n = 427) | ≥6 (n = 98) | <4 (n = 91) | 4–5 (n = 163) | ≥6 (n = 25) | ||||
| Maternal characteristic | |||||||||
| Age at enrollment, y | 32.7 (4.8) | 32 (5.0) | 32.9 (4.3) | 34.8 (4.5) | .0001 | 30.4 (5.5) | 32.4 (5.1) | 33.4 (6.2) | .01 |
| Prepregnancy BMI | 24.6 (5.2) | 24.7 (4.9) | 23.9 (4.5) | 24.6 (5) | .27 | 26.3 (6.7) | 25.2 (6.1) | 25.9 (5.2) | .41 |
| Paternal BMI | 26.5 (3.9) | 27 (3.5) | 26.3 (3.9) | 25.7 (3.5) | .18 | 27.6 (4.5) | 26.7 (3.6) | 27.9 (4.8) | .14 |
| College graduate or more, n (%) | 630 (74.4) | 26 (60) | 352 (82) | 87 (89) | .0003 | 43 (47) | 106 (65) | 16 (64) | .02 |
| Married or cohabitating, n (%) | 799 (94.3) | 38 (88) | 414 (97) | 94 (96) | .02 | 80 (88) | 149 (91) | 24 (96) | .41 |
| Annual household income < $40 000, n (%) | 81 (10.3) | 9 (23) | 25 (6) | 10 (11) | .001 | 15 (19) | 20 (13) | 2 (8) | .36 |
| Child characteristic | |||||||||
| Female gender, n (%) | 426 (50.3) | 16 (37) | 215 (50) | 54 (55) | .15 | 38 (42) | 91 (56) | 12 (48) | .10 |
| Nonwhite race/ethnicity, n (%) | 248 (29.3) | 21 (49) | 117 (27) | 20 (20) | .002 | 37 (41) | 44 (27) | 9 (36) | .08 |
| Birth weight, kg | 3.5 (0.6) | 3.5 (0.5) | 3.5 (0.5) | 3.5 (0.6) | .97 | 3.6 (0.5) | 3.5 (0.6) | 3.3 (0.8) | .15 |
| Gestational age at birth, wk | 39.5 (1.8) | 39.7 (1.4) | 39.6 (1.7) | 39.5 (1.9) | .77 | 39.7 (1.6) | 39.4 (2) | 39.2 (2.1) | .25 |
| Weight-for-age z score at birth, U | 0.1 (1.1) | 0.0 (0.9) | 0.1 (1.0) | 0.1 (1.1) | .81 | 0.2 (1.0) | 0.0 (1.0) | -0.2 (1.4) | .23 |
| Weight-for-age z score at 4 mo, U | 0.5 (1) | 0.4 (1) | 0.4 (0.9) | 0.3 (1.1) | .67 | 0.7 (1.0) | 0.6 (0.9) | 0.1 (1.2) | .01 |
| Change in weight-for-age z score from 0 to 4 mo, U | 0.4 (1) | 0.4 (1.2) | 0.4 (1) | 0.2 (1.1) | .43 | 0.6 (1) | 0.6 (0.9) | 0.3 (1.1) | .32 |
Breastfed was defined as exclusively or partially breastfed at 4 months of age. Formula-fed was defined as exclusively formula-fed since birth or completely weaned from breast milk by 4 months of age. P values are from χ2 tests for categorical characteristics and from unadjusted linear regression for continuous characteristics.