Multi-ethnic reference values for spirometry for the 3–95-yr age range: the global lung function 2012 equations

TLDR

The Task Force aimed to derive globally applicable continuous prediction equations and lower limits of normal for spirometric indices, with plans to refine them using additional data from underrepresented regions. Over 160,000 data points from 72 centres in 33 countries were pooled, cleaned to 97,759 healthy nonsmoker records, and used with the LMS method to derive prediction equations for 3–95‑year‑old healthy individuals across four ethnic groups, with a composite equation for mixed or unrepresented groups. The resulting equations show proportional differences in FEV1 and FVC across ethnic groups, with FEV1/FVC ratios remaining consistent, and provide age‑dependent lower limits of normal that can be applied globally.

Abstract

The aim of the Task Force was to derive continuous prediction equations and their lower limits of normal for spirometric indices, which are applicable globally. Over 160,000 data points from 72 centres in 33 countries were shared with the European Respiratory Society Global Lung Function Initiative. Eliminating data that could not be used (mostly missing ethnic group, some outliers) left 97,759 records of healthy nonsmokers (55.3% females) aged 2.5-95 yrs. Lung function data were collated and prediction equations derived using the LMS method, which allows simultaneous modelling of the mean (mu), the coefficient of variation (sigma) and skewness (lambda) of a distribution family. After discarding 23,572 records, mostly because they could not be combined with other ethnic or geographic groups, reference equations were derived for healthy individuals aged 3-95 yrs for Caucasians (n=57,395), African-Americans (n=3,545), and North (n=4,992) and South East Asians (n=8,255). Forced expiratory value in 1 s (FEV(1)) and forced vital capacity (FVC) between ethnic groups differed proportionally from that in Caucasians, such that FEV(1)/FVC remained virtually independent of ethnic group. For individuals not represented by these four groups, or of mixed ethnic origins, a composite equation taken as the average of the above equations is provided to facilitate interpretation until a more appropriate solution is developed. Spirometric prediction equations for the 3-95-age range are now available that include appropriate age-dependent lower limits of normal. They can be applied globally to different ethnic groups. Additional data from the Indian subcontinent and Arabic, Polynesian and Latin American countries, as well as Africa will further improve these equations in the future.