MethodsF425 healthy school children (213 boys and 212 girls) aged 5 to 14 years old were chosen from kindergarten, primary and middle schools in Beijing urban area. We used peak flow meter (Mini - Wright, AFS) from PARI company of German to measure peak expiratory flow rate and recorded gender, age, height, weight and other physical parameters. Flow-volume curve was carried out using Jaeger spirometry instrument and peak expiratory flow (PEF) values were adopted. The difference peak expiratory flow values between two measures were compared using SPSS13.0 statistical software. Stepwise multiple linear regression was used to derive the regression equations.
Results: The values of PEFR increased along with age among children. There were statistically significant difference between different age groups (P <0.05). The PEFR values of boys were higher than those of girls and the difference between males and females reached significant level at the age of 11, 13 and 14 (P <0.05). Either in boys or girls, PEFR significantly correlated with age, height, weight, the high degree of correlation existed with height and then age and weight. The predicted equations of PEFR reference values was established in children 5-14 years old living in Beijing urban area as follows: PEFR(L/min)=5.29×H|427.1(boys)and PEFR(L/min)=4.94×H|399.8(girls) respectively. The PEFR value measured by peak flow meter (309.1 ± 74.1 L/min) was higher than those measured by spirometry (298.9±91.3 L/min), and the difference between was statistically significant (P < 0.001).
Conclusions: New reference values of the peak expiratory flow rate were determined, and the predicted equations were built for children 5 to 14 years old in Beijing urban area, and providing evidence for the clinical management of respiratory diseases.