Table 3– Association between birth conditions and respiratory outcomes
Ever wheezeCurrent wheezeNight wheezeSevere wheezeWheeze with exerciseAsthmaNight cough
Written questionnaire
 Birthweight g
  <30001.06 (0.99–1.14)0.97 (0.85–1.11)1.08 (0.90–1.28)1.12 (0.89–1.41)1.11 (1.03–1.19)1.17 (1.07–1.28)1.08 (1.02–1.15)
  3000–3499ref.ref.ref.ref.ref.ref.ref.
  ≥35001.02 (0.96–1.08)1.00 (0.89–1.12)1.05 (0.90–1.22)1.23 (1.01–1.49)1.07 (1.01–1.15)0.97 (0.90–1.05)1.03 (0.97–1.08)
 Gestational age weeks
  <371.09 (0.93–1.29)0.97 (0.71–1.33)1.43 (0.95–2.15)1.40 (0.86–2.28)1.04 (0.86–1.25)1.15 (0.93–1.42)1.19 (1.03–1.37)
  37–42ref.ref.ref.ref.ref.ref.ref.
  ≥421.07 (0.92–1.24)1.05 (0.80–1.39)0.89 (0.61–1.31)0.94 (0.58–1.52)1.13 (0.96–1.33)1.14 (0.94–1.37)1.15 (1.01–1.31)
 LBW
  Not LBWref.ref.ref.ref.ref.ref.ref.
  LBW1.11 (0.97–1.27)1.01 (0.79–1.31)1.21 (0.87–1.69)0.99 (0.64–1.52)1.07 (0.92–1.24)1.10 (0.92–1.31)1.11 (0.99–1.25)
 Pre-term#
  Not pre-termref.ref.ref.ref.ref.ref.ref.
  Pre-term1.09 (0.92–1.29)0.97 (0.71–1.32)1.43 (0.95–2.16)1.40 (0.86–2.28)1.04 (0.86–1.25)1.15 (0.93–1.42)1.18 (1.02–1.36)
 SGA
  Not SGAref.ref.ref.ref.ref.ref.ref.
  SGA1.10 (1.01–1.19)1.03 (0.88–1.20)1.01 (0.82–1.24)0.92 (0.70–1.21)1.15 (1.06–1.26)1.17 (1.05–1.30)1.10 (1.03–1.19)
Video questionnaire
 Birthweight g
  <30001.05 (0.96–1.14)0.92 (0.77–1.10)1.12 (1.00–1.25)1.03 (0.94–1.12)1.14 (1.07–1.21)1.09 (1.00–1.20)
  3000–3499ref.ref.ref.ref.ref.ref.
  ≥35001.03 (0.96–1.11)0.95 (0.82–1.10)1.00 (0.90–1.10)0.99 (0.92–1.07)1.06 (1.00–1.12)0.92 (0.85–1.00)
 Gestational age weeks
  <371.01 (0.82–1.25)1.00 (0.65–1.54)1.03 (0.77–1.36)0.99 (0.80–1.21)1.12 (0.97–1.31)1.09 (0.87–1.36)
  37–42ref.ref.ref.ref.ref.ref.
  ≥421.09 (0.91–1.30)1.38 (0.93–2.03)1.09 (0.86–1.39)1.00 (0.84–1.20)1.01 (0.88–1.16)1.15 (0.95–1.39)
 LBW
  Not LBWref.ref.ref.ref.ref.ref.
  LBW1.07 (0.90–1.26)0.98 (0.70–1.38)1.12 (0.90–1.40)1.00 (0.84–1.18)1.16 (1.02–1.30)1.23 (1.04–1.46)
 Pre-term#
  Not pre-termref.ref.ref.ref.ref.ref.
  Pre-term1.01 (0.82–1.25)0.99 (0.64–1.52)1.02 (0.77–1.36)0.99 (0.80–1.21)1.12 (0.97–1.31)1.08 (0.87–1.35)
 SGA
  Not SGAref.ref.ref.ref.ref.ref.
  SGA1.09 (0.98–1.21)1.00 (0.81–1.24)1.17 (1.02–1.34)1.08 (0.98–1.20)1.16 (1.08–1.25)1.19 (1.07–1.32)
  • Data are presented as OR (95% CI). LBW: low birthweight (denotes birth weight <2,500 g); SGA: small for gestational age; ref.: reference group. #: pre-term denotes gestational age <37 weeks. All models were adjusted for parental education level, number of smokers at home, incense burning, active smoking, alcohol use and history of rhinitis and eczema.