[New predictive formulas of pulmonary function in Japanese children]

Socioeconomic conditions, including nutrition, have improved dramatically over the past four decades in Japan. Those improvements have elicited significant changes in the developmental growth and average size of Japanese children. These trends suggest that predictive formulas of pulmonary function need to be revised. Our study enrolled 446 children (222 boys and 224 girls ranging in age from 5 to 16 years) who had no history of respiratory disease. The subjects were examined by spirometry. We formulated regression equations for several measures of ventilatory function by age, weight, and height, including vital capacity (VC), forced vital capacity (FVC), and forced expiratory volume in one second (FEV1.0), using data randomly selected from 70% of the children. Optimum parameters for the equations were selected by calculating Akaike information criteria (AIC) and Mallow's index C (p). The optimum regression equations were tested for their predictive value as acceptable predictive formulas by evaluating data randomly selected from 30% of the children. These new formulas are considered to be better suited for modern-day evaluations of pulmonary function in Japanese children.