Table 1.
Infant Exposures to Antibiotics Over the First Year of Life
| Characteristic | Nursery N = 326 |
Visit 2 N = 211 |
Visit 3 N = 158 |
Visit 4 N = 144 |
|---|---|---|---|---|
| Age, mean (SD, range), y | NA | 4.2 (0.9, 2.2–7.1) | 8.2 (1.3, 6.1–12.4) | 13.4 (1.8, 10.4–19) |
| Infant, N (%)a | ||||
| Antibiotics | ||||
| Yes | 2 (0.6) | 20 (9.5) | 25 (15.8) | 30 (20.8) |
| Yes, including maternal antibiotics during delivery | 156 (47.8) | … | … | … |
| No | 324 | 189 | 132 | 114 |
| Missing | 0 | 2 | 1 | 0 |
| Ever antibiotics (visit cohort) | ||||
| Yes | 2 (0.6) | 22 (10.4) | 36 (22.8) | 48 (33.3) |
| No | 324 | 189 | 122 | 96 |
| Yes, including maternal antibiotics at delivery | 156 (47.8) | 116 (55.0) | 94 (5 | 96 (66.7) |
| Childcare | ||||
| Yes | NA | 45 (21.3) | 45 (28.5) | 49 (34.0) |
| No | … | 164 | 112 | 95 |
| Missing | … | 2 | 1 |
0 |
| Hospitalization | ||||
| Yes | 326 (100) | 22 (10.4) | 10 (6.3) | 11 (7.6) |
| No | 0 | 187 | 147 | 132 |
| Missing | 0 | 2 | 1 | 1 |
| Breastfeeding, any | ||||
| Yes | 224 (68.7) | 49 (23.2) | 20 (12.7) | 11 (7.6) |
| No | 100 | 160 | 137 | 133 |
| Missing | 2 | 2 | 1 | 0 |
| Breastfeeding, exclusive | ||||
| Yes | 111 (34.0) | 24 (11.4) | 11 (7.0) | 10 (7.0) |
| No | 215 | 185 | 146 | 134 |
| Missing | 0 | 2 | 1 | 0 |
| Household a (other than infant) | ||||
| Antibiotics | ||||
| Yes | 193 (59.2) | 33 (15.6) | 17 (10.8) | 9 (6.2) |
| No | 133 | 174 | 140 | 133 |
| Unknown | 0 | 4 | 1 | 1 |
| Childcare | ||||
| Yes | 65 (19.9) | 38 (18.0) | 26 (16.5) | 27 (18.7) |
| No | 261 | 170 | 129 | 117 |
| Unknown | 0 | 3 | 3 | 0 |
| Hospitalization | ||||
| Yes | 326 (100) | 7 (3.3) | 5 (3.2) | 13 (9.0) |
| No | 0 | 202 | 152 | 131 |
| Unknown | 0 | 2 | 1 | 0 |
| Smoking | ||||
| Yes | 158 (48.5) | 92 (43.6) | 64 (40.5) | 63 (43.7) |
| No | 166 | 116 | 93 | 81 |
| Unknown | 1 | 3 | 1 | 0 |
| Any household member age <2 y | ||||
| Yes | 42 (12.9) | 22 (10.4) | 12 (7.6) | 13 (9.0) |
| No | 284 | 186 | 145 | 128 |
| Unknown | 0 | 3 | 1 | 3 |
| Any household member age <5 y | ||||
| Yes | 154 (47.2) | 84 (39.8) | 56 (35.4) | 56 (38.9) |
| No | 172 | 124 | 101 | 85 |
| Unknown | 0 | 3 | 1 | 3 |
| Infant or household antibiotics | ||||
| Yes | 193 (59.2) | 48 (22.7) | 35 (22.1) | 37 (25.7) |
| No | 133 | 161 | 122 | 107 |
| Unknown | 0 | 2 | 1 | 0 |
Abbreviation: NA, not applicable.
aSince previous visit or within previous 4 months if visit was missed or delayed.