Table 2

Adjusted prevalence odds ratios for asthma and atopy outcomes between the categories of birth parameters with the middle category being used as the reference

No.Ever asthma
OR (95% CI)
Drug therapy
OR (95% CI)
Asthma in past 2 years OR (95% CI)BHR OR
(95% CI)
IgE ⩾150 IU*
OR (95% CI)
Skin test +ve (weal ⩾2 mm) OR (95% CI)
Birth length (cm)
 <501031.0  (0.3   to  3.3)1.4  (0.4   to  4.4)1.0  (0.3   to  3.7)1.0  (0.3   to  3.4)1.0  (0.5   to  2.3)0.7  (0.4   to  1.5)
 50–55.95971.01.01.01.01.01.0
 ⩾56346.4 (2.0   to  19.8)4.6 (1.4   to  15.7)3.9 (1.1   to  13.4)0.8 (0.1   to  6.6)0.8 (0.2   to  2.5)1.1 (0.4   to  2.7)
 p value for trend7340.050.110.040.560.420.75
Head circumference (cm)
 <341541.7 (0.8   to  3.9)1.5 (0.7   to  3.5)1.4 (0.6   to  3.4)1.0 (0.3   to  2.7)1.0 (0.5   to  1.9)0.5 (0.3   to  1.0)
 34–36.95311.01.01.01.01.01.0
 ⩾37490.2 (0.1   to  0.9)0.4 (0.1   to  1.6)0.1 (0.0   to  0.9)0.9 (0.2   to  4.3)3.4 (1.4   to  7.9)1.2 (0.6   to  2.8)
 p value for trend7340.860.910.670.260.020.75
Birth weight (kg)
 <3.01500.2 (0.0   to  0.6)0.1 (0.0   to  0.5)0.2 (0.0   to  0.6)0.8 (0.3   to  2.6)0.9 (0.4   to  1.9)0.9 (0.5   to  1.8)
 3.0–3.95011.01.01.01.01.01.0
 ⩾4.0841.0 (0.4   to  2.4)0.5 (0.2   to  1.4)1.2 (0.5   to  3.0)0.4 (0.1   to  1.6)0.6 (0.3   to  1.2)0.6 (0.3   to  1.2)
 p value for trend7350.700.340.690.240.490.47
Older siblings
 02461.01.01.01.01.01.0
 1–23380.7 (0.4   to  1.2)0.8 (0.5   to  1.5)0.6 (0.3   to  1.2)1.0 (0.5   to  2.2)1.3 (0.8   to  2.0)0.9 (0.6   to  1.4)
 3+1510.3 (0.1   to  0.8)0.5 (0.2   to  1.3)0.4 (0.2   to  1.1)0.6 (0.2   to  1.9)2.3 (1.2   to  4.6)0.7 (0.4   to  1.3)
 p value for trend7350.020.090.070.350.140.24
Sex
 Female3551.01.01.01.01.01.0
 Male3801.8 (1.0   to  3.0)1.7 (1.0   to  2.9)1.8 (1.0   to  3.1)1.4 (0.7   to  2.6)1.3 (0.9   to  1.9)1.4 (1.0   to  2.0)
  • The analyses are adjusted for all variables listed in the table (gestational age, maternal smoking, socioeconomic status, and parental history of asthma).