Table 2.
Baseline characteristics of the study population in the WHISTLER-online and usual care group
| WHISTLER-online (n = 323) | Usual care (n = 322) | |
|---|---|---|
| Sex, n (%) boys [N = 645] | 150 (46.4) | 158 (49.1) |
| Birth weight, mean grams (SD) [N = 645] | 3559.4 (509.9) | 3558.4 (490.9) |
| Birth length, mean cm (SD) [N = 606] | 50.6 (2.3) | 50.8 (2.2) |
| Gestational age, mean days (SD) [N = 645] | 278.7 (9.1) | 277.8 (9.8) |
| Maternal asthma in last 12 months, n (%) [N = 583] | 26 (8.7) | 18 (6.4) |
| Maternal allergy (allergy to pollen, house dust mite, food, or pets), n (%) [N = 594] | 110 (36.5) | 108 (36.9) |
| Paternal asthma in last 12 months, n (%) [N = 570] | 16 (5.6) | 13 (4.6) |
| Paternal allergy (allergy to pollen, house dust mite, food, or pets), n (%) [N = 579] | 127 (43.9) | 120 (41.4) |
| Siblings, n (%) with at least one [N=645] | 190 (58.8) | 197 (61.2) |
| Pet ownership during pregnancy, n (%) [N = 645] | 124 (38.4) | 124 (38.5) |
| Maternal smoking during pregnancy, n (%) [N = 643] | 15 (4.6) | 18 (5.6) |
| Maternal higher education, n (%) [N = 588] | 227 (76.4) | 217 (74.6) |
| Birth season, n (%) [N = 645] | ||
| Winter | 76 (23.5) | 72 (22.4) |
| Spring | 90 (27.9) | 89 (27.6) |
| Summer | 93 (28.8) | 80 (24.8) |
| Autumn | 64 (19.8) | 81 (25.2) |
| Age of the mother at birth, mean years (SD) | 32.7 (4.0) | 33.0 (4.6) |
| Ethnicity mother, n (%) Western [N = 599] | 275 (90.8) | 264 (89.2) |
| Ethnicity father, n (%) Western [N = 584] | 268 (91.8) | 263 (90.1) |
SD = standard deviation.