The ratio FEV1/FVC and its association to respiratory symptoms—A Swedish general population study

Research output: Contribution to journalArticle


Chronic airflow limitation (CAL) can be defined as fixed ratio of forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) < 0.70 after bronchodilation. It is unclear which is the most optimal ratio in relation to respiratory morbidity. The aim was to investigate to what extent different ratios of FEV1/FVC were associated with any respiratory symptom. In a cross-sectional general population study, 15,128 adults (50–64 years of age), 7,120 never-smokers and 8,008 ever-smokers completed a respiratory questionnaire and performed FEV1 and FVC after bronchodilation. We calculated different ratios of FEV1/FVC from 0.40 to 1.0 using 0.70 as reference category. We analysed odds ratios (OR) between different ratios and any respiratory symptom using adjusted multivariable logistic regression. Among all subjects, regardless of smoking habits, the lowest odds for any respiratory symptom was at FEV1/FVC = 0.82, OR 0.48 (95% CI 0.41–0.56). Among never-smokers, the lowest odds for any respiratory symptom was at FEV1/FVC = 0.81, OR 0.53 (95% CI 0.41–0.70). Among ever-smokers, the odds for any respiratory symptom was lowest at FEV1/FVC = 0.81, OR 0.43 (95% CI 0.16–1.19), although the rate of inclining in odds was small in the upper part, that is FEV1/FVC = 0.85 showed similar odds, OR 0.45 (95% CI 0.38–0.55). We concluded that the odds for any respiratory symptoms continuously decreased with higher FEV1/FVC ratios and reached a minimum around 0.80–0.85, with similar results among never-smokers. These results indicate that the optimal threshold associated with respiratory symptoms may be higher than 0.70 and this should be further investigated in prospective longitudinal studies.


  • Kjell Torén
  • Linus Schiöler
  • Anne Lindberg
  • Anders Andersson
  • Annelie F. Behndig
  • Göran Bergström
  • Anders Blomberg
  • Kenneth Caidahl
  • Jan E. Engvall
  • Maria J. Eriksson
  • Christer Janson
  • David Kylhammar
  • Eva Lindberg
  • Anders Lindén
  • Andrei Malinovschi
  • Hans Lennart Persson
  • Martin Sandelin
  • Jonas Eriksson Ström
  • Jenny Vikgren
  • Carl Johan Östgren
  • C. Magnus Sköld
External organisations
  • Sahlgrenska University Hospital
  • Umeå University
  • University of Gothenburg
  • Karolinska Institutet
  • Linköping University
  • Karolinska University Hospital
  • Skåne University Hospital
  • Uppsala University
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Respiratory Medicine and Allergy


  • chronic airflow limitation, COPD, cough with phlegm, dyspnoea, GOLD, SCAPIS, wheeze
Original languageEnglish
JournalClinical Physiology and Functional Imaging
Publication statusE-pub ahead of print - 2020 Dec 7
Publication categoryResearch