Global Lung Function Initiative 2012 reference values for spirometry in South Italian children.

Area of Science:

• Pulmonology
• Pediatric Respiratory Health
• Public Health

Background:

• The Global Lung Function Initiative (GLI) 2012 reference values are widely used for spirometry.
• Local applicability of these global reference values requires validation.
• Accurate interpretation of spirometry is essential for diagnosing respiratory conditions in children.

Purpose of the Study:

• To assess the applicability of GLI 2012 spirometry reference equations in a large population of normal schoolchildren from Sicily, Southern Italy.
• To compare the performance of GLI 2012 equations against previous prediction equations for spirometry interpretation.

Main Methods:

• Evaluation of GLI equations in 1243 healthy schoolchildren (aged 7-16 years).
• Testing normality assumptions for GLI z-scores (FEV1, FVC, FEV1/FVC) and deriving bootstrap confidence intervals.
• Comparison of GLI and other reference equations based on the probability of falling below the lower limit of normal (LLN).

Main Results:

• Normality assumption for GLI z-scores held for males but not for females (p < 0.001).
• GLI 2012 equations showed underestimation for FEV1/FVC (0.75 males, 0.81 females) and FVC, and slight underestimation for FEV1.
• GLI, Hankinson, and Quanjer equations accurately predicted the probability of FEV1 < LLN; Wang and Pistelli equations showed accuracy for FVC and FEV1/FVC respectively in specific groups.

Conclusions:

• The GLI 2012 reference values underestimate FEV1/FVC in a sample of normal South Italian children.
• Physicians should be cautious and validate reference values locally before interpreting spirometry results.
• This study highlights the need for geographically specific reference values in pediatric pulmonology.