Characteristics n (%)a
Total 2568 (100%)
Sex
female 1257 (48.9)
male 1311 (51.1)
Age, years
1 424 (16.5)
2 405 (15.8)
3 411 (16.0)
4 400 (15.6)
5 415 (16.2)
6-7 513 (20.0)
Family socioeconomic status
Low
667 (26.1)
Medium or high
1889 (73.9)
Maternal smoking during pregnancy
Yes
364 (14.2)
No
2199 (85.8)
Second-hand smoke exposure during pregnancy
Yes
101 (5.11)
No
1874 (94.9)