Objective To construct a predictive equation of pulmonary function parameters in healthy children aged 11 to 12 years in Yangzhou.

Methods A total of 595 healthy children aged 11 to 12 years old from 5 primary schools in Yangzhou were prospectively selected as subjects, including 334 males and 261 females. Lung function instrument was used to measure their lung ventilation function. Taking measured values of peak expiratory flow (PEF), forced vital capacity (FVC), forced expiratory volume in the first second (FEV₁) and FEV₁ to FVC ratio (FEV₁/FVC) as dependent variables and age, height, body mass and body mass index as independent variables, mean value of relative prediction error is used to evaluate the applicability of the prediction equation.

Results Height, body weight, body mass index, PEF, FEV₁ and FVC of 12-year-old boys were higher than those of 11-year-old boys, and height, body mass, body mass index, systolic blood pressure, diastolic blood pressure, FEV₁ and FVC levels of 12-year-old girls were higher than those of 11-year-old girls, and the differences were statistically significant (P < 0.05). The blood pressure and body mass index of the 11-year-old boys were higher than those of the 11-year-old girls, and the height of the 12-year-old boy was lower than that of the 12-year-old girls, and the body mass index of the 12-year-old boys was higher than that of the 12-year-old girls (P < 0.05). Correlation analysis showed that age, height, body mass and body mass index of boys were positively correlated with PEF, FEV₁ and FVC (P < 0.01), and height was negatively correlated with FEV₁/FVC (P < 0.01). The height, body mass and body mass index of girls were positively correlated with FEV₁ and PEF (P < 0.01 or P < 0.05), and the age was positively correlated with FEV₁ (P < 0.01). The prediction equations for the reference values of each index in boys were PEF(L/s)=0.032H+0.261A-4.306, FEV₁(L)=0.028H+0.092A-3.098 and FVC(L)=0.042H+0.101A-4.858; the prediction equations for the reference values of each index in girls were PEF(L/s)=0.032H+0.261A-4.306, FEV₁(L)=0.028H+0.092A-3.098 and FVC(L)=0.042H+0.101A-4.858, H referring to height (cm) and A referring to age (years old). The results of the equation test compared with the predicted equations of other studies, and the regression equation constructed in this time had better applicability to the study group in the research.

Conclusion In this study, the predicted equation of the main parameters of pulmonary ventilation function in children aged 11 to 12 years in Yangzhou can help to predict the related parameters of lung ventilation function of children in this area, thereby laying a foundation for the accurate diagnosis of children's lung function abnormalities in clinic.