Quanjer et al. (GLI-2012)
About this reference
The Global Lung Function Initiative 2012 (GLI-2012) equations are a widely adopted reference standard for spirometry, developed by the European Respiratory Society and endorsed on release by the ATS, ANZSRS, TSANZ, APSR, and ACCP. Quanjer and colleagues pooled 97,759 subjects from 33 countries and fitted LMS-based regression equations for FEV1, FVC, FEV1/FVC, and other indices by age, height, sex, and ethnicity. The resulting equations replaced a patchwork of older national reference sets and are widely implemented in clinical spirometry software. Note that the equations are ethnicity-specific: in a 2023 official statement the ATS recommended against race- and ethnicity-specific reference equations and now favours race-neutral interpretation (Bhakta et al. 2023). Percentiles on this site are computed from the coefficient set GLI labels "Caucasian" at NHANES median heights for each age-sex bracket (Fryar et al. 2021, DOI: 10.15620/cdc:103734).
Known limitations
- Percentiles shown use the coefficient set GLI labels "Caucasian" only; in the GLI-2012 model the African American values are approximately 10-15% lower, North East Asian approximately 4% lower, South East Asian approximately 9-12% lower (GLI-2012 Table 3). The ATS 2023 statement recommends against applying these ethnicity-specific adjustments and favours race-neutral interpretation (Bhakta et al. 2023, DOI 10.1164/rccm.202302-0310ST)
- Values computed at median heights from NHANES; individuals notably taller or shorter will have different expected FEV1
- Sample sizes for ages 80+ are small (n < 200 per sex in Table E3); interpret upper-age percentiles with caution
- Reference equations were developed from healthy never-smokers and ex-smokers; population-average values in high-smoking-prevalence cohorts will be lower