Global Lung Function Initiative reference equations better describe a middle-aged, healthy French population than the European Community for Steel and Coal values

Extract

Spirometry plays a pivotal role in the clinical evaluation and management of respiratory diseases. Pulmonary function varies with age, height, sex and ethnicity, and test results need to be compared with predicted values and lower limits of normal (LLN) and upper limits of normal (ULN), that are appropriate for the individual being tested [1]. The European Community for Steel and Coal (ECSC) first published reference spirometric values for healthy non-smokers in 1983 based on a collation of regression equations [2]. In 2012, the Global Lung Function Initiative (GLI) presented prediction equations derived from measured values of a large population [1]. These newer statistical procedures provided us for the first time with a single equation for ages from 3 years through to 95 years. Measured values are converted to z-scores which describe how many standard deviations a measured value differs from the predicted value and these are independent of sex, age and height.