Spirometric reference values for healthy Han children aged 5-15 years in Guangzhou, southern China.

Background: Reliable interpretation of spirometry rests on appropriate reference values, but there are few published reference values for healthy children in China.

Objective: To develop the updated spirometric normative values for healthy children aged 5-15 years in Guangzhou, southern China, and to explore the differences by comparison with published reference values.

Methods: In this cross-sectional study, health questionnaire and physical examination conducted for screening healthy Han children. Spirometry was performed by well-trained technicians according to American Thoracic Society guidelines. Using Lambda-Mu-Sigma (LMS) algorithm, predicted equations for the median and lower limits of normal were derived for forced vital capacity (FVC), forced expiratory volume in one second (FEV1 ), peak expiratory flow (PEF), and maximal mid-expiratory flow (FEF25-75% ). Predicted values were compared with other published spirometric reference equations.

Results: Data were obtained from 422 healthy children (226 boys and 196 girls) aged 5-15 years. Spirometric parameters showed moderate-to-strong positive correlations with age, height, and weight in both genders, with height being the most crucial predictor. There were significant differences between spirometric values and other published reference values. Spirometric values were comparable with the data derived from the same area population in 2002, with exception of increased height and weight in the equivalent age groups.

Conclusions: The present spirometric reference equations are feasible for assessment of lung function among children in southern China. Further studies for establishment of reference values for Chinese children in other regions are needed.