Pulmonary function growth velocity in children 6 to 18 years of age.

Pulmonary function growth rate varies with a child's stage of growth. Since attained pulmonary function reflects the cumulative effects of growth, insults, and repair, rate of growth may be a more sensitive indicator of a child's current pulmonary health status. The sample for analyses included 2,478 white boys and 2,785 white girls followed annually by questionnaire and spirometry. Empirically derived annual growth velocities, peak velocity (Vpk), and age at which peak velocity occurred (Agepk) were determined for height, FVC, FEV1, and FEF25-75 for each child. Mean velocity curves for height, FVC, FEV1, and FEF25-75, stratified by sex and Agepk of height (an indicator for early, middle, or late maturity) were produced as a function of age. The differences between Agepk of FVC, FEV1, and FEF25-75 and Agepk of height (i.e., the lag period) were compared by sex and by the indicator of maturity. Linear regression analyses were performed to investigate associations between Vpk and Agepk of height, as well as between the lag period and Agepk of height. As is generally observed in height growth, there were considerable variations in the age of onset and magnitudes of the adolescent growth spurts of the pulmonary function parameters both between sexes and among children of the same sex. The duration of adolescent growth spurt appeared to be similar for all children, regardless of early, middle, or late maturity. Thus, those who matured earlier had shorter total growth periods than those who matured later. On the other hand, early maturers had greater growth velocities during preadolescence and greater adolescent Vpk than later maturers.(ABSTRACT TRUNCATED AT 250 WORDS)