Table 2

Birth characteristics of subjects with and without asthma in a sample of Danish twin pairs, 3–9 years of age

MeasureAsthma
Yes n=1155No n=9618Difference (95% CI)p Value
Birth weight24672589122 (87 to 158)<0.001
Birth length47.5448.140.60 (0.39 to 0.81)<0.001
Birth BMI10.9311.170.23 (0.14 to 0.32)<0.001
Gestational age250.50255.024.52 (3.32 to 5.72)<0.001
Apgar score9.699.740.05 (−0.01 to 0.11)0.120
Current age6.235.830.41 (0.29 to 0.53)<0.001
Sex
 Males12.787.31.00
 Females8.791.30.65 (0.58 to 0.74)<0.001
Zygosity
 MZ11.888.21.00
 DZ10.789.30.90 (0.77 to 1.05)0.183
  • Measures are mean values except for sex and zygosity (prevalence). Birth weight is in g, birth length is in cm, BMI is in kg/m2, gestational age is in days, current age is years.

  • Means and proportions are calculated from available data for the individual variables.

  • Sex and zygosity difference are ORs.

  • BMI, body mass index; DZ, dizygosity; MZ, monozygosity.