Table 1. Characteristics of the study population.
| N | Total | % | |
|---|---|---|---|
| Subject characteristics | |||
| Sex, male | 553 | 1097 | 50.4 |
| Sibling (s), >0 | 451 | 1096 | 41.2 |
| Birthweight, g, median, percentiles 25, 75 | 2965 | 2715, 3235 | |
| Environmental exposure | |||
| Pet ownership | 187 | 1095 | 17.1 |
| Environmental tobacco smoke at 3y | 341 | 1086 | 31.4 |
| TV viewing at 3y >3h on weekends | 95 | 1091 | 8.7 |
| Income <4,000,000 yen/year | 93 | 1025 | 9.1 |
| Maternal characteristics | |||
| Maternal age, y, media, percentiles 25, 75 | 34 | 31, 36 | |
| Maternal education level, lowa | 262 | 1052 | 24.9 |
| Maternal asthma | 156 | 1097 | 14.2 |
| Maternal atopic dermatitis | 163 | 1097 | 14.9 |
| Maternal rhinitis | 554 | 1097 | 50.5 |
| Maternal asthma, atopic dermatitis or rhinitis | 639 | 1097 | 58.2 |
| Health assessment of children | |||
| Breastfeeding before age 6 months | 164 | 1079 | 15.20 |
| BMI Z-score at 3y, median, percentiles 25,75 | 0.14 | -0.45, 0.65 | |
| Evaluation at 3y and 5y | |||
| Swimming lessons at 3y | 126 | 1095 | 11.5 |
| Ever wheeze at 3y | 265 | 1095 | 24.2 |
| Ever rhinitis at 3y | 299 | 1088 | 27.5 |
| Current wheeze at 5y | 180 | 1096 | 16.4 |
| Atopic dermatitis | 231 | 1095 | 21.1 |
| Current rhinitis at 5y | 387 | 1096 | 35.3 |
TV: television, 3y: age 3 years, 5y: age 5 years, 6M: age 6 months
amaternal education level, low, middle school, high or vocational school