Table 4

Mean and 95% CIs of post-bronchodilator forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) residuals at age 11, 16, 22 and 26 years and of their linear trends between age 11 and 26 years across parental and active smoking groups

 FEV1/FVC residuals YR11FEV1/FVC residuals YR16FEV1/FVC residuals YR22FEV1/FVC residuals YR26Linear trends of FEV1/FVC residuals per year from YR11 to YR26
NMean (95% CI)NMean (95% CI)NMean (95% CI)NMean (95% CI)NMean (95% CI)
Parental smoking
 No2780.37 (−0.25 to 1.00)2550.06 (−0.64 to 0.76)3020.36 (−0.26 to 0.98)2250.36 (−0.36 to 1.09)321−0.01 (−0.08 to 0.06)
 Yes133−0.77 (−1.65 to 0.11)121−0.13 (1.08 to 0.82)147−0.73 (−1.61 to 0.15)115−0.71 (−1.66 to 0.24)156−0.08 (−0.14 to −0.01)
p Value0.040.750.0490.080.18
Active smoking, 16–26 years
 No267−0.07 (−0.69 to 0.56)250−0.13 (−0.82 to 0.56)298 0.12 (−0.49 to 0.74)2240.31 (−0.41 to 1.04)314−0.01 (−0.07 to 0.06)
 Yes1440.12 (−0.75 to 0.99)1260.26 (−0.71 to 1.23)151−0.24 (−1.15 to 0.66)116−0.61 (−1.56 to 0.35)163−0.07 (−0.16 to 0.02)
p Value0.720.520.500.140.054
Combined smoking groups
ParentalActive, 16–26 years
 NoNo1950.31 (−0.42 to 1.03)185−0.12 (−0.95 to 0.71)219 0.41 (−0.31,1.13)163 0.41 (−0.47 to 1.29)229−0.00 (−0.09 to 0.08)
 NoYes830.50 (−0.67 to 1.67)700.54 (−0.78 to 1.86)830.22 (−1.02 to 1.46)620.24 (−1.03 to 1.51)92−0.02 (−0.14 to 0.11)
 YesNo72−1.08 (−2.29 to 0.12)65−0.17 (−1.44 to 1.11)79−0.66 (−1.84 to 0.52)610.06 (−1.20 to 1.31)85−0.02 (−0.11 to 0.06)
 YesYes61−0.39 (−1.72 to 0.94)56−0.10 (−1.56 to 1.37)68−0.81 (−2.17 to 0.55)54−1.58(−3.02 to −0.13)71−0.14 (−0.25 to −0.03)
p Value0.180.840.260.130.16
  • YR11, age 11 years; YR16, age 16 years; YR22 age 22 years; YR26, age 26 years.