Pulmonary-Function Testing
Trained technicians assisted the students in performing
pulmonary-function maneuvers that met
the standards of the American Thoracic Society,
as described elsewhere.8 For each child, maximal
forced expiratory volume in 1 second (FEV1)
and forced vital capacity (FVC) were measured.
For cohorts C and D, pulmonary-function testing
was performed annually from 4th through 12th
grade (mean ages, 10 to 18 years), with the use
of rolling-seal spirometers. In cohort E, pulmonary-
function testing was performed every other
year, when the children were approximately 11,
13, and 15 years of age, with the use of pressure
transducer–based spirometers. Of the 2120 children,
1585 (74.8%) were tested at the beginning
(age 11 years) and end (age 15 years) of the follow-
up period, whereas the remaining 535 children
(25.2%) were tested at 11 but not at 15 years
of age.