Table 1. Demographic and risk factors at enrollment of completed cases.
| Characteristics of study population | First episode of AOM treated with oral antibiotics | ||
|---|---|---|---|
| No (n = 336) | Yes (n = 512) | p-value | |
| Gender, n (%) | |||
| Male | 166 (49.4%) | 276 (53.9%) | 0.20 |
| Female | 170 (50.6%) | 236 (46.1%) | |
| Parental education level, n (%) | |||
| High educated | 258 (76.8%) | 395 (77.1%) | 0.90 |
| Middle/low educated | 78 (23.2%) | 117 (22.9%) | |
| Season of birth, n (%) | |||
| Spring | 80 (23.8%) | 148 (28.9%) | 0.12 |
| Summer | 92 (27.4%) | 124 (24.2%) | |
| Fall | 67 (19.9%) | 119 (23.2%) | |
| Winter | 97 (28.9%) | 121 (23.6%) | |
| Number of siblings, median (IQR) | 0 (0–1) | 1 (0–1) | 0.02 |
| Presence of older siblings, n (%) | |||
| 0–4 years old | 161 (82.1%) | 282 (79.4%) | 0.48 |
| 5–8 years old | 26 (13.3%) | 60 (16.9%) | |
| 9–12 years old | 9 (4.6%) | 13 (3.7%) | |
| Duration of exclusive breastfeeding, n (%) | |||
| No or only partial breastfeeding | 59 (17.6%) | 117 (22.9%) | 0.37 |
| <3 months | 160 (47.6%) | 224 (43.8%) | |
| 3–6 months | 79 (23.5%) | 111 (21.7%) | |
| >6 months | 38 (11.3%) | 60 (11.7%) | |
| Household-smoking during first year, n (%) | |||
| No smoking | 261 (77.7%) | 418 (81.6%) | 0.36 |
| 1–5 months of smoking | 58 (17.3%) | 74 (14.5%) | |
| ≥ 6 months of smoking | 17 (5.1%) | 20 (3.9%) | |
| Age at entry to daycare, n (%) | |||
| <3 months | 43 (12.8%) | 65 (12.7%) | 0.96 |
| 3–5 months | 196 (58.3%) | 297 (58.0%) | |
| 6–12 months | 40 (11.9%) | 67 (13.1%) | |
| No daycare attendance during first year of life | 57 (17.0%) | 83 (16.2%) | |
| Age of first AOM episode in months, mean (SD) | 9.9 (5.1) | 11.3 (5.2) | <0.001 |
| Number of prescribed oral antibiotics, prior to the first AOM episode, n (%) | |||
| 0 | 298 (88.7%) | 435 (85.0%) | 0.07 |
| 1 | 38 (11.3%) | 71 (13.9%) | |
| ≥2 | 0 (0%) | 6 (1.2%) | |
Abbreviations: AOM, acute otitis media. SD, standard deviation. IQR, interquartile range.