The range from 11 to 15 years of age was
targeted because it covers the overlapping age
period of pulmonary-function testing across cohorts.
Follow-up over this age range was conducted
In addition to examining 4-year growth from
11 to 15 years of age, we analyzed the crosssectional
pulmonary-function measurements obtained
for 1585 children at the end of this period
(mean age, 15 years) to determine whether
changes in air quality over time were associated
with clinically important deficits in attained FEV1
and FVC. Using data from all three cohorts, we
developed a linear prediction model for FEV1
that included adjustments for age