Prevalence and underdiagnosis of airway obstruction among middle-aged adults in northern France: The ELISABET study 2011-2013.

Introduction: Airway obstruction (AO), mainly due to chronic obstructive pulmonary disease (COPD) in adults, is a major cause of mortality and poor quality of life. However, few data are available for France. This study was designed to calculate the prevalence AO among middle-aged adults in northern France, explore the associated risk factors and evaluate the underdiagnosis.

Methods: The Enquête Littoral Souffle Air Biologie Environnement (ELISABET) was a cross-sectional study of a representative sample of 3276 adults aged from 40 to 64 in two urban areas in northern France (Lille and Dunkirk). Participants filled out a questionnaire and performed spirometry testing, without a reversibility test.

Results: The age-standardized estimated prevalence [95% confidence interval] of AO was 16.0% [13.9; 17.9] in Lille and 13.7% [11.7; 15.7] in Dunkirk with the Global initiative for chronic Obstructive Lung Disease (GOLD) definition and 10.8% [9.2; 12.5] and 9.5% [7.9; 11.2] respectively with the lower limit of normal calculated with the Global Lung Initiative (GLI) 2012 equations. AO was associated with age, male gender, tobacco consumption and low body mass index. The underdiagnosis rate was greater than 70%. Previously undiagnosed participants with AO displayed more respiratory symptoms compared with participants without AO and less than participants with previously diagnosed AO.

Conclusion: The prevalence of AO in northern France ranged from 9.5 to 16.0%, depending on the centre and definition used. The high underdiagnosis rate observed here suggests that greater efforts should be made to identify individuals presenting with the symptoms and/or risk factors associated with AO.