Determination of reference values of lung function in children aged 5-14 years in Beijing

Abstract

Objective To assess the lung function of healthy children aged 5 to 14 years and to determine the spirometric reference values and predicted value equations of children living in Beijing. Methods Four hundred and twenty-six healthy children (213 boys and 213 girls) aged 5 to 14 years from kindergartens and primary schools in Beijing were included in the study.Tests of lung function were carried out in all children.The tests included measurement of flow-volume curve, maximal per minute ventilation (MVV) and peak expiratory flow rate (PEFR) by using Jaeger Masterscreen spirometry machine and portable peak flow meter.Lung function parameters including forced vital capacity (FVC), forced expiratory volume in 0.5 second, forced expiratory volume in 1 second (FEV1), FEV1/FVC, maximal mid-expiratory flow rate, peak expiratory flow, forced expired flow at 25% of FVC, forced expired flow at 50% of FVC, forced expired flow at 75% of FVC, forced expiratory time, MVV, and PEFR were recorded.Stepwise multiple linear regression was adopted to derive the regression equations. Results The value of lung function parameters increased significantly along with the increasing of age among children aged 5 to 14 years (all P<0.01). No significant difference was found in values of major lung function parameters between males and females except for the 13 and 14 age groups.The lung function values of PEFR, FVC, FEV1, MVV were significantly higher in boys than those in girls aged 13 and 14 years(all P<0.01). Lung function level was positively correlated with age, height and weight.The strongest correlation was found between FEV1 and height which was followed by age and weight.Reference values and regression equations of children aged 5 to 14 years in Beijing were established. Conclusions Reference values of major lung function parameters by PEFR, MVV were determined, and the predicted value equations were established in children aged 5 to 14 years in Beijing, which would help the pediatric clinicians to make accurate evaluation of patients' condition. Key words: Lung function; Spirometry; Reference value; Child