RT Journal Article
SR Electronic
T1 Chronic airflow limitation and its relation to respiratory symptoms among ever-smokers and never-smokers: a cross-sectional study
JF BMJ Open Respiratory Research
JO BMJ Open Resp Res
FD British Thoracic Society
SP e000600
DO 10.1136/bmjresp-2020-000600
VO 7
IS 1
A1 Kjell Toren
A1 Linus Schiöler
A1 Anne Lindberg
A1 Anders Andersson
A1 Annelie F Behndig
A1 Göran Bergström
A1 Anders Blomberg
A1 Kenneth Caidahl
A1 Jan Engvall
A1 Maria Eriksson
A1 Viktor Hamrefors
A1 Christer Janson
A1 David Kylhammar
A1 Eva Lindberg
A1 Anders Lindén
A1 Andrei Malinovschi
A1 Hans Lennart Persson
A1 Martin Sandelin
A1 Jonas Eriksson Ström
A1 Hanan A Tanash
A1 Jenny Vikgren
A1 Carl Johan Östgren
A1 Per Wollmer
A1 C. Magnus Sköld
YR 2020
UL http://bmjopenrespres.bmj.com/content/7/1/e000600.abstract
AB Background The diagnosis of chronic obstructive pulmonary disease is based on the presence of persistent respiratory symptoms and chronic airflow limitation (CAL). CAL is based on the ratio of forced expiratory volume in 1 s to forced vital capacity (FEV1:FVC) after bronchodilation, and FEV1:FVC less than the fifth percentile is often used as a cut-off for CAL. The aim was to investigate if increasing percentiles of FEV1:FVC were associated with any respiratory symptom (cough with phlegm, dyspnoea or wheezing) in a general population sample of never-smokers and ever-smokers.Methods In a cross-sectional study comprising 15 128 adults (50–64 years), 7120 never-smokers and 8008 ever-smokers completed a respiratory questionnaire and performed FEV1 and FVC after bronchodilation. We calculated their z-scores for FEV1:FVC and defined the fifth percentile using the Global Lung Function Initiative (GLI) reference value, GLI5 and increasing percentiles up to GLI25. We analysed the associations between different strata of percentiles and prevalence of any respiratory symptom using multivariable logistic regression for estimation of OR.Results Among all subjects, regardless of smoking habits, the odds of any respiratory symptom were elevated up to the GLI15–20 strata. Among never-smokers, the odds of any respiratory symptom were elevated at GLI<5 (OR 3.57, 95% CI 2.43 to 5.23) and at GLI5–10 (OR 2.57, 95% CI 1.69 to 3.91), but not at higher percentiles. Among ever-smokers, the odds of any respiratory symptom were elevated from GLI<5 (OR 4.64, 95% CI 3.79 to 5.68) up to GLI≥25 (OR 1.33, 95% CI 1.00 to 1.75).Conclusions The association between percentages of FEV1:FVC and respiratory symptoms differed depending on smoking history. Our results support a higher percentile cut-off for FEV1:FVC for never-smokers and, in particular, for ever-smokers.