[Studies of normal values and prediction equations for pulmonary function--spirometry and flow-volume measurements in healthy Japanese children 6 to 14 years of age].

We analyzed spirometric data (spirograms and flow-volume curves) on 1,357 healthy Japanese children (6-14 yr, 709 males and 648 females) in Higashimatsuyama, Saitama. The area was selected as the representative of the less polluted area in Japan, as we intended to exclude possible effects of air-pollution on spirometric values. Hot-wire anaemometers (AS 3500, AS 4500, MINATO) were used in the spirometry and the test procedures were done following the American Thoracic Society recommendations. By multiple regression analysis prediction equations were obtained for VC, FVC, FEV1, FEV1/FVC (%), MMFR, PEFR (Peak Expiratory Flow Rate), V75, V50, and V25. The selected variables were height and weight for VC, FVC and FEV1 but only height for MMFR, PEFR, V75, V50 and V25. Since there was no significant correlations between FEV1/FVC (%) and these variables, we defined normal ranges for FEV1/FVC (%). The predicted values derived from our equations were larger than those obtained from the other studies published in Japan. The difference is probably due to the improvement in the body size of Japanese children and the equipments used.