TABLE 1.
Characteristics of Infants With Bronchiolitis (Cases) and Healthy Infants (Controls)
| Characteristics | Infants With Bronchiolitis (Cases), n = 40 | Healthy Infants (Controls), n = 115 | P |
|---|---|---|---|
| Demographics | |||
| Age, mo, mean (SD) | 4 (3) | 4 (2) | .76 |
| Male gender | 18 (55) | 64 (56) | .99 |
| Race or ethnicity | .04 | ||
| Non-Hispanic white | 23 (57) | 61 (53) | |
| Non-Hispanic black | 6 (15) | 11 (10) | |
| Hispanic | 10 (25) | 19 (17) | |
| Other | 1 (2) | 24 (21) | |
| Parental history of asthma | 16 (40) | 21 (18) | .01 |
| Prenatal history | |||
| Maternal smoking during pregnancy | 8 (20) | 3 (3) | .001 |
| Maternal antibiotic use during pregnancy | 11 (29) | 13 (11) | .02 |
| Maternal antibiotic use during labor | 12 (34) | 35 (30) | .82 |
| Past medical history and home environmental characteristics | |||
| Mode of birth | .13 | ||
| Vaginal birth | 31 (78) | 72 (63) | |
| Cesarean delivery | 9 (22) | 43 (37) | |
| Prematurity (32–37 wk) | 12 (30) | 11 (10) | .004 |
| Previous breathing problems before enrollmenta | 8 (21) | 0 (0) | <.001 |
| History of eczema | 8 (21) | 17 (15) | .56 |
| Ever attended day care | 9 (23) | 14 (12) | .16 |
| Sibling at home | 34 (87) | 47 (41) | <.001 |
| Smoking exposure at home | 8 (21) | 4 (3) | .002 |
| Mostly breastfed for the first 3 mo of age | 16 (52) | 89 (77) | .009 |
| Systemic antibiotic use before enrollment | 8 (21) | 13 (11) | .24 |
| Systemic corticosteroid use before enrollment | 9 (23) | 0 (0) | <.001 |
| Hospitalization course | |||
| Hospital length-of-stay, d, median (IQR) | 3 (2–4) | — | — |
| Admission to ICU | 8 (20) | — | — |
| Use of mechanical ventilationb | 5 (16) | — | — |
Data are no. (%) of infants unless otherwise indicated. Percentages may not equal 100 because of missingness or rounding. —, not computed.
a
Defined as an infant having a cough that wakes him or her at night or causes emesis, or when the child has wheezing or shortness of breath without cough.
b
Defined as use of continuous positive airway pressure or intubation during inpatient stay, regardless of location at any time during the index hospitalization.