Parameter estimated by multiple linear regression analysis models for FVC, FEV1, and FEF25–75% as dependent variables and sex, age class, height, and weight as independent variables.

aThis parameter is set to zero because it is redundant*β coefficients indicate how much a dependent variable changes per each unit variation of the independent variable, taking into account the effect of the other independent variables in the model. For categorical variables, β coefficients represent the effect of moving from the “reference” category (a) to anotherData are shown for 2,393 asymptomatic children.Parameter estimated by multiple linear regression analysis models for FVC, FEV1, and FEF25–75% as dependent variables and sex, age class, height, and weight as independent variables.