Analysis Of Influencing Factors Of Lung Function In Children In Northeast China And Establishment Of Predicted Value Equation

Objective:To analysis influence factors of lung function,using the related influencing factors as the independent variable to establish the reference value equation of different lung function parameters.Methods:Five hundred and eighty-one healthy children and adolescents aged 6-16 years were selected randomly from primary and middle schools in the three provinces of Heilongjiang,Jilin,Liaoning,their gender,age,height,weight,history and family history were recorded,had their spirometry done with the German jaeger company Master Screen pneumo type instrument and measured their lung function parameters,including FVC,FEV₁,FEV₁/FVC,PEF,FE_F25,FEF₅₀,FEF₇₅.At last,excluded datas of objects who had allergy history,previous wheezing history,404 subjects were finally included,and SPSS25.0 was used for data statistics.Results:1.There was no significant difference in age,height and weight between boys and girls,but there was significant difference in BMI（P<0.05）,and the male were higher than the female;2.Lung function parameters of FVC,FEV₁,FEV₁/FVC,PEF,FEF₂₅,FEF₅₀,FEF₇₅and VBE in boys in the 14-16 year old group were higher than those in girls,and the difference was statistically significant.The overall trend of lung function parameters increased with age regardless of gender.3.Correlation analysis of lung function parameters showed that FVC,FEV₁ were positively correlated with age,height and weight,and males higher than females;PEF and MMEF were positively correlated with age,height and weight,but had no significant correlation with gender.4.Predicted value equations are established for different lung function parameters,with A representing age,S representing gender（male 0,female 1）,H representing height,and W representing weight.The equations are as follows:FVC=-2.763+0.074ⅹA+0.028ⅹH+0.011ⅹW-0.239ⅹS FEV₁=-2.598+0.076ⅹA+0.026ⅹH+0.009ⅹW-0.144ⅹS PFE=-3.599+0.173ⅹA+0.039ⅹH+0.017ⅹW-0.292ⅹS MMEF=-3.765+0.114ⅹA+0.035ⅹH5.By comparing FVC and FEV₁ reference value equation with other equations,the mean relative prediction errors of FVC of our equation,SEA-GLI2012 equation and Zapletal equation are 12.6%,12.6%and 16.1%,respectively.The mean relative prediction error of Zapletal equation for FVC are higher than which of our study and SEA-GLI2012 equation.The mean relative prediction errors of FEV₁ of the equation in our study,SEA-GLI2012equation and Zapletal equation are 13.1%,12.7%and 13.3%,respectively,and there is no significant difference in the relative prediction errors of FEV₁ among the three equations.Conclusion:1.Pulmonary function parameters showed an increasing trend with age regardless of gender,and the lung function level of male adolescents over 14 years old was higher than that of female adolescents;2.Lung function parameters FVC and FEV₁were positively correlated with age,height and weight,and higher in boys than in girls;PEF and small airway function parameters（MMEF）were positively correlated with age,height and weight,but not with gender;3.Based on the data,the predicted value equations of different parameters are established;4.Compared with Zapletal value equation,the mean relative prediction error of FVC in our study is slightly lower,but there is no difference between our equation and SEA-GLI2012.For the prediction of FEV₁,the mean relative prediction errors of the three equations are not significantly different.