Applicability of the Global Lung Function Initiative prediction equations in Hong Kong Chinese children

Background and ObjectiveThis study aimed to assess the applicability of the Global Lung Function Initiative (GLI) prediction equations for spirometry in Hong Kong children and to develop prediction equations based on the Generalized Additive Models for Location, Scale, and Shape (GAMLSS) modeling.MethodsHealthy Chinese children and adolescents aged 6-17 years old were recruited from randomly selected schools to undergo spirometry. The measurements were transformed to z-score according to the GLI-2012 equations for South East (SE) Asians and the GLI-2022 global race-neutral equations. Prediction equations for spirometric indices were developed with GAMLSS modeling to identify predictors.ResultsA total of 886 children (477 boys) with a mean age of 12.5 years (standard deviation [SD] 3.3 years) were included. By the GLI-2012 SE Asian equations, positive mean z-scores were observed in forced expiratory volume in 1 s (FEV1) (boys: 0.138 & PLUSMN; SD 0.828; girls: 0.206 & PLUSMN; 0.823) and forced vital capacity (FVC) (boys: 0.160 & PLUSMN; 0.930; girls: 0.310 & PLUSMN; 0.895) in both sexes. Negative mean z-scores were observed in FEV1/FVC ratio (boys: -0.018 & PLUSMN; 0.998; girls: -0.223 & PLUSMN; 0.897). In contrast, negative mean z-scores in FEV1 and FVC, and positive mean z-scores in FEV1/FVC were observed when adopting the GLI-2022 race-neutral equations. The mean z-scores were all within the range of & PLUSMN;0.5. By GAMLSS models, age and height were significant predictors for all four spirometric indices, while weight was an additional predictor for FVC and FEV1.ConclusionOur study provided data supporting the applicability of the GLI prediction equations in Hong Kong Chinese children. The GLI-2012 equations may underestimate FEV1 and FVC, while the GLI-2022 equations may overestimate the parameters, but the differences lie within the physiological limits. By GAMLSS modeling, weight was an additional predictor for FVC and FEV1.