Spirometric reference equations for healthy children aged 6 to 11 years in Taiwan.

BACKGROUND Spirometry is a valuable technique for evaluating pulmonary function, but there were few normative reference values for young children in Taiwan, and none for the last 10 years. The objective of our study was to establish updated reference values and equations for children aged 6-11 years in northern Taiwan. METHODS A total of 309 healthy children (153 boys and 156 girls) were enrolled in the present study. The data of at least 3 trials for each child were collected, and the highest values analyzed. The analyzed pulmonary function parameters were focused on forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), peak expiratory flow rate (PEF), forced expiratory flow between 25% and 75% expired volume (FEF25-75), and the ratio of FEV1/FVC. RESULTS The results revealed that there were mostly no significant differences between boys and girls, and the standing height (H, cm) was the factor with the highest correlation with the pulmonary function parameters. Regression equations of the major pulmonary function parameters for both boys and girls were obtained: FVC = -2.690 + 0.0330H; FEV1 = -2.559 + 0.0311H; PEF = -300.231 + 3.938H; FEF25-75 = -3.218 + 0.0425H (p < 0.001). CONCLUSION Our study determined the updated normative values and reference equations for Chinese children aged 6-11 years living in northern Taiwan. These values can be used as normative reference values to evaluate pulmonary function in diseased children with the same ethnicity and lifestyle.