Age Dependency of GLI Reference Values Compared with Paediatric Lung Function Data in Two German Studies (GINIplus and LUNOKID)

Abstract

A hallmark of the newly published GLI (Global Lungs Initiative) spirometric reference values is their "all-age" (3-95yr) predictive power, accomplished by incorporating non-linear age dependencies into modelling parameters. This modelling strategy is especially promising for the age range of puberty; however, the performance of GLI-values for adolescents is currently unknown. We calculated GLI-based z-scores for children/adolescents without apparent respiratory diseases from two different German studies, LUNOKID (N = 1943, 4–19 years) and GINIplus (N = 1042, 15 years) and determined the goodness of fit for specific age groups. We defined fit sufficient if the absolute mean of z-scores was <0.5. For children (<10yr) the mean GLI-based z-scores for FEV1 and FVC reached a good fit with mean z-scores for FEV1 between -0.11 and 0.01 and mean z-scores for FVC between 0.01 and 0.16, but larger deviations were observed in adolescents, especially boys (mean z-score -0.58 for FEV1 and -0.57 for FVC in GINIplus). The fit for FEV1/FVC was sufficient. GLI reference values provided reasonable estimates for the individuals enrolled in our studies, which span the age range of lung growth and development. However, we found that GLI-predictions overestimated lung volumes, especially those for German adolescent boys, which may, left unrecognised, lead to erroneous diagnosis of lung disease. Caution should be taken when applying these reference values to epidemiologic studies.

How applicable are GLI 2012 equations to a sample of Middle Eastern school‐age children?

“…One limitation to this study is that although the LLN produced by GLI 2012 for Caucasians was not significantly different from the expected 5% except for FVC in boys, high LLN values were reported in several parameters, these high LLN values can be attributed to the age spread of the studied group that may produce high variance in the sample data, as indicated by the standard deviations of the z scores that were above 1 in many parameters. The high variance in this age group was reported in previous studies 33 that attributed this variance to puberty, in which a significant decrease in z scores, which was independent of height, gender, or age, was reported 34 particularly among boys 33 . Differences in puberty age between countries are well documented, 35 unfortunately, such information about Jordanian children is lacking.…”

“…The high variance in this age group was reported in previous studies 33 that attributed this variance to puberty, in which a significant decrease in z scores, which was independent of height, gender, or age, was reported 34 particularly among boys. 33 Differences in puberty age between countries are well documented, 35 unfortunately, such information about Jordanian children is lacking.…”

Lung function trajectories using different reference equations in a birth cohort study up to the age of 20 years

“…This may be due to the fact that at this puberty age, lung development is still occurring in boys, whereas lung development is almost finished in girls. A similar observation was made in a cross-sectional study by HÜLS et al [14], applying GLI reference equations to original lung function data from LUNOKID and GINIplus (German Infant Study on the Influence of Nutrition Intervention plus Air pollution and Genetics on Allergy Development) at the age of 15 years. The authors underline that height development and therefore lung volume increase varies much between Caucasian populations, especially in puberty when growth in males is rapid.…”

Higher serum 25(OH)D concentrations are associated with improved FEV1and FVC in adolescence

“…We therefore consider a reverse causation unlikely. Moreover, the standardised z-scores according to GLI did not fit very well to the current study population [42]. Thus, the regression models calculated for the association between serum 25(OH)D concentrations and GLI z-scores were also adjusted for sex as well as age and height at lung function measurement.…”