Abstract
Background: Understanding the natural history of abnormal spirometric patterns at different stages of life is critical to identify and optimise preventive strategies. We aimed to describe characteristics and risk factors of restrictive and obstructive spirometric patterns occurring before 40 years (young onset) and between 40 and 61 years (mid-adult onset).Methods: We used data from the population-based cohort of the European Community Respiratory Health Survey (ECRHS). Prebronchodilator forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were assessed longitudinally at baseline (ECRHS1, 1993–1994) and again 20 years later (ECRHS3, 2010–2013). Spirometry patterns were defined as: restrictive if FEV1/FVC≥LLN and FVC<10th percentile, obstructive if FEV1/FVC