Spirometric pulmonary function parameters of healthy Chinese children aged 3-6 years in Taiwan

Spirometry is a well-known technique for evaluating pulmonary function, but few studies have focused on preschool children. The aim of this study was to determine reference values of forced spirometric parameters in young Chinese children, aged 3-6 years, in Taiwan. Spirometric measurements were performed at day care centers by experienced pediatricians. Of 248 children without a history of chronic respiratory illness, at least two valid spirometric attempts were obtained from 214 children (109 boys and 105 girls; age: 36-83 [mean = 61] months; height: 90-131 [mean = 111] cm). Values of forced expiratory volume in 1 sec (FEV1) and 0.5 sec (FEV(0.5)), forced vital capacity (FVC), peak expiratory flow rate (PEF), forced expiratory between 25% and 75% FVC (FEF(25-75)), and forced expiratory flow rate at 25%, 50%, and 75% of FVC (FEF(25), FEF(50), and FEF(75)) were derived and analyzed. There were significant positive correlations between study parameters and body height, body weight, and age. Height was the most consistently correlated measurement in both boys and girls. Although boys tended to have higher spirometric values than girls, we found significant differences only in FVC and FEV1 between boys and girls aged 6 years. The regression equations of each parameter were obtained. In conclusion, spirometric pulmonary function tests are feasible in 3- to 6-year-old children. The obtained values and regression equations provide a reference for Chinese preschool children and may be of value in evaluating pulmonary function of children with respiratory problems in this age group.