Table 1 Infant, parent, and household characteristics at time of study enrollment a
Characteristics | Study formula-fed only (n = 140) | Breastfed only (n = 136) | Mixed-fed (breastfed and study formula-fed) (n = 151) | P-valueb |
|---|---|---|---|---|
Infants | ||||
 Age, days | 42.2 ± 3.6 | 42.3 ± 3.7 | 42.5 ± 3.4 | 0.75 |
 Gestational age, weeks | 38.6 ± 1.0 | 39.0 ± 1.0 | 38.9 ± 1.0 | 0.004 |
 Weight, kgc | 4.9 ± 0.5 | 5.0 ± 0.5 | 5.0 ± 0.5 | ND |
 Sex, % male | 70 (50.0) | 78 (57.4) | 93 (61.6) | 0.13 |
 Birth order, % first birth | 116 (82.9) | 122 (89.7) | 129 (85.4) | 0.34 |
 Type of delivery, % Cesarean | 82 (58.6) | 66 (48.5) | 85 (56.3) | 0.21 |
 Attend day care | 0 | 0 | 0 | 1.00 |
Mothers | ||||
 Education, years | 14.6 ± 2.8 | 15.8 ± 3.0 | 15.3 ± 2.8 | 0.002 |
 Occupation |  |  |  | 0.53 |
  Professional | 42 (30.0) | 51 (37.5) | 55 (36.4) |  |
  Service or retail | 23 (16.4) | 21 (15.4) | 22 (14.6) |  |
  Homemaker | 32 (22.9) | 17 (12.5) | 27 (17.9) |  |
Fathers | ||||
 Education, years | 14.7 ± 3.0 | 15.6 ± 2.8 | 15.4 ± 3.0 | 0.031 |
 Occupation |  |  |  | 0.28 |
  Professional | 25 (17.9) | 28 (20.6) | 30 (19.9) |  |
  Service or retail | 31 (22.1) | 34 (25.0) | 34 (22.5) |  |
  Technician/associate professional | 22 (15.7) | 25 (18.4) | 21 (13.9) |  |