Prevalence of small airway dysfunction in the Swiss PneumoLaus Cohort

Abstract

Background.Recent evidence identified exposure to particulate matter of size ≤2.5 µm (PM2.5) as a risk factor for high prevalence of small airway dysfunction (SAD). We assessed the prevalence of SAD in a European region with low air pollution levels.Methods.SAD was defined as a maximum mid-expiratory flow (MMEF) <65% of predicted value (PV) or MMEF<lower limit of normal (LLN) measured by spirometry in the Swiss PneumoLaus cohort. We performed bivariate and multivariable analysis with MMEF criteria, age, gender, body mass index (BMI), respiratory symptoms, and smoking status. Mean PM2.5values were obtained from a Swiss national database.Results.Among 3351 participants (97.6% Caucasian, 55.8% female sex, mean age 62.7 years), we observed MMEF <65% PV in 425 (12.7%) and MMEF<LLN in 167 (5.0%) individuals. None of the participants had both MMEF<LLN and ≥65% PV. MMEF <65% PV and MMEF<LLN were significantly associated with age, smoking status, cough, sputum, dyspnoea, whereas a positive association with MMEF <65% PV was observed for individuals aged >65 years only. In an area where ambient PM2.5concentration was <15 µg·m−3during the observation period (2010 and 2020), ≥72% of participants with SAD were ever smokers.Conclusions.The observed low prevalence of SAD of 5.0–12.7% depending on criteria employed may be related to lower PM2.5exposure. Smoking was the main factor associated with SAD in an area with low PM2.5exposure. Employing a MMEF threshold <65% PV carries a risk of SAD overdiagnosis in the elderly individuals.

Associations of Depressive and Anxiety Disorders with Pulmonary Disorders in the Community: The PneumoLaus and PsyCoLaus Studies

“…In the lack of an internationally accepted gold standard for the definition of small airways dysfunction (SAD) [24], we used the MMEF to define SAD, reflecting the impact of a reduced MMEF highlighted in other studies [25]. We defined SAD when the MMEF before BD was below the LLN according to expert recommendations and local data [24][25][26].…”