Abstract
Why was the cohort set up? Chronic obstructive pulmonary disease (COPD) affects 5– 10% of people worldwide,1 is rising in prevalence2 and is the third most common cause of death.3 The annual burden of COPD regarding healthcare (mainly exacerbations resulting in emergency admissions) and societal (predominantly lost productivity) costs was estimated to be around $49.9 billion in the USA (2010 prices4) and E48.4 billion in the EU (2011 prices5). A substantial proportion of those with COPD are of working age, but there is some evidence that they have poorer employment history,6 higher rate of sickness absence7 and poorer work performance (presenteeism) 8 compared with the general population.