We thank P. Degens and R. Merget for giving us the opportunity to comment on the reference equations suggested by the American Thoracic Society/European Respiratory Society Task Force on lung function testing 1.
We agree with P. Degens and R. Merget when they say that the European Community for Coal and Steel reference equations for lung function are too old to be used in modern medicine due to their limitations in predicting lung function in the general population. Recognising this as an unresolved issue in the evaluation of lung function, the Task Force did not actually recommend “any specific set of equations for use in Europe”; instead, it suggested “the need for a new Europe-wide study to derive updated reference equations for lung function” 1. The latter appears to be the central issue raised by P. Degens and R. Merget with regard to the article 1. The authors state that it is not necessary to move on with the European project as updated equation references already exist 2. This is where we are compelled to disagree.
Apart from the fact that the Swiss Cohort Study on Air Pollution and Lung Diseases in Adults (SAPALDIA) was cited along with many others in table 1 of the article 1, we are not convinced that a study conceived to derive only simple spirometric parameters, in a limited central European area and over a modest lifespan, could qualify as a comprehensive set of references for a continent. While it is important to appreciate the scientific level of the SAPALDIA, which meets standard methodological, epidemiological and statistical criteria, we believe that the new European references should include not only spirometry but also lung volumes, diffusing lung capacity for carbon monoxide and perhaps other tests, all possibly derived from the same subjects; it should cover most of the countries, and expand the lifespan as much as possible owing to the continuous ageing forecast.
With this in mind, and in the same way as many other national studies conducted in Europe over recent years that are listed in American Thoracic Society/European Respiratory Society document, the Swiss Cohort Study on Air Pollution and Lung Diseases in Adults reinforces the need for periodically updating the reference values. While waiting for the possibility to perform a new pan-European study, perhaps through a pool of private and public grants, the availability of the Swiss Cohort Study on Air Pollution and Lung Diseases in Adults reference values will certainly be of great help for the Swiss pulmonary function test laboratories.
Statement of interest
None declared.
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