Table 1

Estimation of district-specific FVC growth by linear mixed effects model

ParameterCity A vs City BPM2.5PM10
Estimate (95% CI) (mL)P valueEstimate (95% CI) (mL)P valueEstimate (95% CI) (mL)P value
Intercept−2051.1 (−2112.1, −1990.1)<0.001−2045.8 (−2108.2, −1983.4)<0.001−2057.5 (−2120.1, −1994.8)<0.001
Time146.4 (140.4, 152.3)<0.001185.6 (175.8, 195.5)<0.001201.8 (190.9, 212.8)<0.001
Air pollution−158.4 (−169.1, −147.6)<0.001−16.8 (−18.5, −15.1)<0.001−8.7 (−9.7, −7.7)<0.001
Time×air pollution−71.3 (−78.4, −64.2)<0.001−12.2 (−13.4, −11.0)<0.001−8.1 (−8.9, −7.4)<0.001
Baseline age87.9 (83.5, 92.2)<0.00184.9 (80.5, 89.3)<0.00184.4 (80.0, 88.8)<0.001
Boys132.7 (123.5, 141.9)<0.001133.3 (124.0, 142.6)<0.001133.3 (124.0, 142.6)<0.001
BMI12.3 (11.0, 13.6)<0.00111.5 (10.2, 12.8)<0.00111.5 (10.2, 12.8)<0.001
Height18.4 (17.8, 19.1)<0.00119.1 (18.4, 19.7)<0.00119.2 (18.5, 19.8)<0.001
  • BMI, body mass index; FVC, forced vital capacity.

  • The effect of air pollution on FVC growth was assessed by including an interaction term between air pollutant (City A vs City B or PM concentrations) and time since enrollment in the linear mixed effects model in 21 616 primary school students. Estimates for PM2.5 and PM10 were calculated based on every 10-mg/m3 increase.