@article {Cerveri1040, author = {I Cerveri and A G Corsico and S Accordini and R Niniano and E Ansaldo and J M Ant{\'o} and N K{\"u}nzli and C Janson and J Sunyer and D Jarvis and C Svanes and T Gislason and J Heinrich and J P Schouten and M Wjst and P Burney and R de Marco}, title = {Underestimation of airflow obstruction among young adults using FEV1/FVC }, volume = {63}, number = {12}, pages = {1040--1045}, year = {2008}, doi = {10.1136/thx.2008.095554}, publisher = {BMJ Publishing Group Ltd}, abstract = {Background: Early detection of airflow obstruction is particularly important among young adults because they are more likely to benefit from intervention. Using the forced expiratory volume in 1 s (FEV1) to forced vital capacity (FVC) (FEV1/FVC) \<70\% fixed ratio, airflow obstruction may be underdiagnosed. The lower limit of normal (LLN), which is statistically defined by the lower fifth percentile of a reference population, is physiologically appropriate but it still needs a clinical validation.Methods: To evaluate the characteristics and longitudinal outcomes of subjects misidentified as normal by the fixed ratio with respect to the LLN, 6249 participants (aged 20{\textendash}44 years) in the European Community Respiratory Health Survey were examined and divided into three groups (absence of airflow obstruction by the LLN and the fixed ratio; presence of airflow obstruction only by the LLN; presence of airflow obstruction by the two criteria) for 1991{\textendash}1993. LLN equations were obtained from normal non-smoking participants. A set of clinical and functional outcomes was evaluated in 1999{\textendash}2002.Results: The misidentified subjects were 318 (5.1\%); only 45.6\% of the subjects with airflow obstruction by the LLN were also identified by the fixed cut-off. At baseline, FEV1 (107\%, 97\%, 85\%) progressively decreased and bronchial hyperresponsiveness (slope 7.84, 6.32, 5.57) progressively increased across the three groups. During follow-up, misidentified subjects had a significantly higher risk of developing chronic obstructive pulmonary disease and a significantly higher use of health resources (medicines, emergency department visits/hospital admissions) because of breathing problems than subjects without airflow obstruction (p\<0.001).Conclusions: Our findings show the importance of using statistically derived spirometric criteria to identify airflow obstruction.}, issn = {0040-6376}, URL = {https://thorax.bmj.com/content/63/12/1040}, eprint = {https://thorax.bmj.com/content/63/12/1040.full.pdf}, journal = {Thorax} }