Table 1

Characteristics of children and their mothers

  n=5197
Maternal characteristics
 Education, higher (%) 51.6 (2685)
 Body mass index at intake (kg/m2) 24.6 (4.25)
 Parity, nullipara (%) 56.6 (2942)
 Smoking during pregnancy, yes (%) 14.0 (729)
 Psychiatric symptoms during pregnancy (GSI)* 0.17 (0.06, 0.38)
 Pet keeping, yes (%) 38.1 (1982)
 History of asthma or atopy, yes (%) 37.2 (1936)
 Mode of delivery, caesarian section (%) 13.6 (709)
Children’s characteristics
 Female sex (%) 50.5 (2,626)
 Gestational age at birth (weeks)* 40.0 (39.1, 41.0)
 Preterm birth <37 weeks (%) 4.3 (223)
 Birth weight (g) 3444 (550)
 Breastfeeding never (%) 8.1 (419)
 Day care attendance 1st year, yes (%) 58.2 (3025)
 Environmental tobacco smoke exposure first 2 years, yes (%) 19.3 (1005)
 Use of antibiotics 1st year, yes (%) 63.0 (3278)
 Use of paracetamol 1st year, yes (%) 87.8 (4569)
 Inhalant allergic sensitisation at age 10 years, yes (%) 31.8 (1.172)
 FEV1 (L) 2.02 (0.30)
 FEV1 (Z-score) 0.17 (0.97)
 FVC (L) 2.33 (0.36)
 FVC (Z-score) 0.21 (0.93)
 FEV:FEV (%) 86.6 (5.7)
 FEV1:FVC (Z-score) −0.11 (0.95)
 FEF75 (L/s) 1.14 (0.35)
 FEF75 (Z-score) 0.00 (0.91)
 Current asthma, yes (%) 5.5 (252)
 Early wheezing, yes (%) 59.5 (1828)
 Late wheezing, yes (%) 20.0 (690)
  • Values are means (SD), valid percentages (absolute numbers) or * medians (25%–75% range) based on imputed data. Data on FVC (available n=4672), FEV1 (n=4672), FEV1:FVC ratio (n=4672), forced expiratory flow when 75% of the FVC is exhaled (FEF75) (n=4672), current asthma (n=4556) and early (n=3074) and late (n=3443) wheezing were not imputed.

  • GSI, Global Severity Index.