Reference values for spirometry
The sets of reference values issued by the ECSC [1-2] were based on males working in coal mines and steel works. This was not a representative reference population, and in practice the predicted values were deemed to be too high. Even though no women had been tested, the ECSC issued reference values for females: they were 80% of the values for males. In 1983 the ECSC declined allocating funds for a population study to derive reference values obtained with methods that complied with the latest standards. With a view to combining technical recommendations with appropriate prediction equations, and because no material was available that had been obtained with appropriate techniques, for lack of better alternatives the standardisation committee decided to adopt the technique previously applied by Polgar  when deriving reference equations for children. This entailed the generation of a set of predicted values for age, height and sex using published prediction equations, and using this artificially generated set to derive new regression equations. Serious objections can be raised against this procedure, but the resulting regression equations were accepted with scarcely any criticism and subsequently widely adopted.
An alternative that the ECSC standardisation group would have welcomed as a good alternative to a new population study was to derive new regression equations from collated good quality measurements, complying with temporal recommended standards; such data were not available. The first use of collated datasets for deriving predicted values for children was based on 6 data sets from 5 European countries . This study showed that the resulting reference values fit 5 of the 6 data sets; it transpired that the sixth set had been affected by a technical problem. Thus this approach was validated; it led to recommending the American Thoracic Society (ATS) and European Respiratory Society (ERS) to support this technique with a view to deriving reference values based on large groups with a wide age range .
In 2005 the European tradition of combining standardisation reports with sets of recommended predicted values came to an end: a joint ATS/ERS committee  recommended predicted values for the United States and Canada, leaving the rest of the world uncovered. In 2006 one of us (PHQ) started to remedy the deficiency, aiming to cover as large an age range as possible as well as various ethnic groups. In 2008 over 30,000 records had been generously made available from all over the world, and a manuscript was being prepared, but this was suspended because an ERS working group with the same objectives was founded. This group subsequently acquired ERS “Task Force” status in 2010, and the support of 6 large international societies . 2008 was also the year of the groundbreaking publication from Stanojevic et al. , applying a new and very powerful statistical technique on collated spirometric data from whites in the 3-80 year age range.
The collaborative work in the group that was named “Global Lung Function Initiative”  was a privilege thanks to the effective and friendly cooperation, based on mutual respect and trust, with some 70 groups from all over the globe. The analytical work was performed by the “Analytical Team”.
|The Analytical Team of the Global Lung Function Initiative. From left to right: Prof. Tim Cole, Prof. Janet Stocks, Prof. Philip Quanjer, Dr. Sanja Stanojevic.|
- Jouasset D. Normalisation des épreuves fonctionnelles respiratoires dans les pays de la Communauté Européenne du Charbon et de l’Acier. Poumon Coeur 1960; 16: 1145–1159.
- Cara M, Hentz P (1971). Aide-mémoire of spirographic practice for examining ventilatory function, 2nd edn. (Industrial Health and Medicine series, vol 11) pp. 1-130.
- Polgar, G, Promadhat V. Pulmonary function testing in children: techniques and standards. Philadelphia, WB Saunders C, 1971.
- Quanjer PH, Borsboom GJ, Brunekreef B, et al. Spirometric reference values for white European children and adolescents: Polgar revisited. Pediatr Pulmonol 1995;19: 135-142. PubMed
- Miller MR, Hankinson J, Brusasco V, et al. ATS/ERS Task Force. Standardisation of spirometry. Eur Respir J 2005; 26: 319-338. Link
- Stanojevic S, Wade A, Stocks J, et al. Reference ranges for spirometry across all ages. A new approach. Am J Respir Crit Care Med 2008; 177: 253–260.PubMed