Table 6

Risk of low lung function (FEV1 <80% predicted) in preschoolers aged 4.5 years in relation to exposure levels of air pollutants

ExposureN low/normal lung functionRR(95% CI)p Value
 Entire pregnancy112/4531.13(0.93 to 1.36)0.208
 First trimester112/4531.10(0.92 to 1.33)0.270
 Second trimester112/4531.22(1.02 to 1.46)0.027
 Third trimester112/4531.15(0.96 to 1.37)0.134
 First year of life111/4481.03(0.86 to 1.23)0.768
 Entire pregnancy112/4541.18(0.85 to 1.63)0.324
 First trimester112/4541.10(0.81 to 1.48)0.545
 Second trimester112/4541.30(0.97 to 1.76)0.080
 Third trimester112/4541.21(0.89 to 1.64)0.222
 First year of life111/4491.01(0.74 to 1.36)0.962
 Recent exposure*112/4541.31(0.87 to 1.97)0.193
 Current exposure†108/4151.13(0.84 to 1.51)0.410
 Recent exposure*112/4541.16(0.91 to 1.49)0.230
 Current exposure†108/4151.05(0.90 to 1.22)0.553
  • All models adjusted for area of study, birth weight, maternal social class, maternal education level, maternal smoking in pregnancy and paternal smoking in pregnancy, environmental tobacco smoke 0–14 months, and lower respiratory tract infections 0–14 months.

  • *One-year average before lung function testing.

  • †One-week average before lung function testing.

  • NO2, nitrogen dioxide; NOX, nitrogen oxides; RR (95% CI), Relative Risk and 95% CIs for anIQR increase in exposure estimated by log-binomial regression.