β coefficients^* estimated by multiple linear regression analysis for FVC, FEV₁, FEV_25–75%, FEV₁/FVC, and FEV_25–75%/FVC as dependent variables and sex, height, and weight as independent variables, separately for each age class (≤11, 12, 13, and ≥14 years), among 2,393 asymptomatic children.

*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 another Only the β coefficients relevant to weight are shown, with 95% confidence interval (95%CI). Significant β coefficients are presented in bold. β coefficients* estimated by multiple linear regression analysis for FVC, FEV1, FEV25–75%, FEV1/FVC, and FEV25–75%/FVC as dependent variables and sex, height, and weight as independent variables, separately for each age class (≤11, 12, 13, and ≥14 years), among 2,393 asymptomatic children.