Table 1: Characteristics of students with asthma and nonasthmatic control subjects.

CharacteristicsStudents with asthmaNonasthmatic control students value

Gender (%)
 Male147 (56.1)580 (45.4)0.002
 Female115 (43.9)697 (54.6)
Birth order (%)
 1123 (46.9)640 (50.1)0.639
 297 (37.0)470 (36.8)
 328 (10.7)117 (9.2)
 412 (4.6)39 (3.1)
 ≥52 (0.8)11 (0.9)
In utero exposure to smoking (%)
 Yes221 (84.4)1140 (89.3)0.021
 No41 (15.6)136 (10.7)
Gestational age (weeks) (%)
 <3665 (25.5)303 (24.4)0.494
 36–40176 (69.0)853 (68.8)
 >4014 (5.5)84 (6.8)