Characteristics n (%)
Sex Sex 3,089
Boy 1,576 (51.0)
Girl 1,513 (49.0)
Asthma incidence Asthma incidence 2,934
Age 0-12 months 78 (2.7)
Age 12-24 months 140 (4.8)
Age 24-36 months 88 (3.0)
Age 0-36 months 306 (10.4)
None 2,628 (89.6)
Wheezing incidence Wheezing incidence 2,934
Age 0-12 months 586 (20.0)
Age 12-24 months 398 (13.6)
Age 24-36 months 134 (4.6)
Age 0-36 months 1,118 (38.1)
None 1,816 (61.9)
Total serum IgE level in 2-year-old children Total serum IgE level in 2-year-old children 2,900
High: ≥180 IU/mL 282 (9.7)
Low: <180 IU/mL 2,618 (90.3)
Total serum IgE level during pregnancy Total serum IgE level during pregnancy 3,089
High: ≥214 IU/mL 557 (18.0)
Low: <214 IU/mL 2,532 (82.0)
Urinary cotinine level in mid-pregnancy Urinary cotinine level in mid-pregnancy 3,089
>36.8 μg/g creatinine 175 (5.7)
0.31–36.8 μg/g creatinine 1,022 (33.1)
<0.31 μg/g creatinine 1,892 (61.2)
Passive smoke after birth Passive smoke after birth 3,089
Yes 863 (27.9)
No 2,226 (72.1)
Presence of indoor pets Presence of indoor pets 3,089
Yes 543 (17.6)
No 2,546 (82.4)
Lower respiratory tract inflammation Lower respiratory tract inflammation 3,089
Yes 471 (15.2)
No 2,618 (84.8)
Respiratory syncytial virus infection Respiratory syncytial virus infection 3,089
Yes 606 (19.6)
No 2,483 (80.4)
Area Area 3,089
Cold area 1,025 (33.2)
Warm low-humidity area 1,202 (38.9)
Warm high-humidity area 862 (27.9)