Changes in the normal maximal expiratory flow-volume curve with growth and aging.

TLDR

The study aimed to develop sex‑ and age‑specific prediction equations for five spirometric and flow‑volume variables and to propose normal limits that account for inter‑subject variability and non‑Gaussian distributions. Using 697 nonsmoking healthy adults from a longitudinal Tucson cohort, the authors selected the best flow‑volume test from the first three surveys, extracted peak values for FVC and FEV1, and derived additional measurements from the test with the highest sum FEV, then applied these data to generate the equations. The resulting equations reveal how development, maturation, and senescence influence ventilatory function across age groups.

Abstract

On the basis of their answers to a self-administered questionnaire, 697 nonsmoking healthy subjects were chosen from a randomly selected sample representative of the white non-Mexican-American population of Tucson, Arizona, enrolled in a longitudinal study of respiratory health. For each subject, the first satisfactory set of flow-volume data obtained during the first 3 consecutive surveys was selected for analysis. For forced vital capacity (FVC) and forced expiratory volume in one second (FEV1), the single best value for each subject was selected. Other flow-volume measurements were derived from the single test with the best sum FEV, plus FVC. These data were used to derive improved prediction equations for each sex by age group for 5 spirometric and flow-volume variables. The resulting predicted values demonstrate the effects of development, maturation, and senescence on ventilatory function. "Normal" limits are proposed that take into consideration the between-subject variability and non-Gaussian distribution of the various measurements.