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Chronic Airflow Limitation, Emphysema, and Impaired Diffusing Capacity in Relation to Smoking Habits in a Swedish Middle-aged Population

A. Blomberg, K. Torén, P. Liv, Gabriel Granåsen, Anders Andersson, A. Behndig, G. Bergström, J. Brandberg et al.

Annals of the American Thoracic Society, 2024

28,746 participants · 11 citations

Abstract

Rationale Chronic obstructive pulmonary disease (COPD) includes respiratory symptoms and chronic airflow limitation (CAL). In some cases, emphysema and impaired diffusing capacity of the lung for carbon monoxide (DlCO) are present, but characteristics and symptoms vary with smoking exposure. Objective To study the prevalence of CAL, emphysema, and impaired DlCO in relation to smoking and respiratory symptoms in a middle-aged population. Methods We investigated 28,746 randomly invited individuals (52% women) aged 50–64 years across six Swedish sites. We performed spirometry, DlCO testing, and high-resolution computed tomography and asked for smoking habits and respiratory symptoms. CAL was defined as post-bronchodilator forced expiratory volume in 1 second divided by forced vital capacity (FEV1/FVC) < 0.7. Results The overall prevalence was 8.8% for CAL, 5.7% for impaired DlCO (DlCO < LLN), and 8.8% for emphysema, with a higher prevalence in current smokers than in ex-smokers and never-smokers. The proportion of never-smokers among those with CAL, emphysema, and impaired DlCO was 32%, 19%, and 31%, respectively. Regardless of smoking habits, the prevalence of respiratory symptoms was higher among people with CAL and impaired DlCO than those with normal lung function. Asthma prevalence in never-smokers with CAL was 14%. In this group, asthma was associated with lower FEV1 and more respiratory symptoms. Conclusions In this large population-based study of middle-aged people, CAL…

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