Young and middle-aged adults with airflow limitation according to lower limit of normal but not fixed ratio have high morbidity and poor survival: a population-based prospective cohort study

A presumed consequence of using a fixed ratio for the definition of airflow limitation (AFL) has been overdiagnosis among older individuals and underdiagnosis among younger individuals. However, the prognosis of younger individuals with potentially underdiagnosed AFL is poorly described. We hypothesised that potential underdiagnosis of AFL at a younger age is associated with poor prognosis.We assigned 95 288 participants aged 20-100 years from...