Table 3—

Twin correlations, cross-trait correlations and cross-trait, cross-twin correlations for asthma, eczema and rhinitis across zygosity and sex groups

MZMDZMMZFDZFOS-mfOS-fm
Twin pairs n128613941509134313921346
Twin correlations
 Asthma0.890.370.920.470.400.44
 Eczema0.830.270.850.320.240.36
 Rhinitis0.930.550.970.370.610.54
Within-twin, cross-trait correlations
 Asthma–eczema0.450.340.370.330.350.28
 Asthma–rhinitis0.480.480.490.520.440.52
 Eczema–rhinitis0.380.430.370.350.320.41
Cross-trait, cross-twin correlations
 Asthma–eczema0.430.050.340.180.090.06
 Asthma–rhinitis0.380.210.430.280.190.18
 Eczema–rhinitis0.350.170.350.150.250.15
  • MZM: monozygotic male twin pairs; DZM: dizygotic male twin pairs; MZF: monozygotic female twin pairs; DZF: dizygotic female twin pairs; OS-mf: opposite sex twin pairs, with male as the first born and female as the second born; OS-fm: opposite sex twin pairs, with female as the first born and male as the second born.