To the Editor:Chronic obstructive pulmonary disease (COPD) is a major cause of mortality and disability worldwide (1). The clinical course of COPD is characterised by exacerbations, which can be minor and manageable at home or in primary care, or severe, leading to hospitalisation or even death. Known causes of exacerbations include tobacco smoke, air pollution, dusts and fumes, and respiratory infections (1, 2). One less well understood risk factor is stress, which could plausibly lead to COPD exacerbations as it can trigger inflammation (3, 4) and is associated with increased smoking (5), which are both implicated in COPD pathology (2). Work is an important source of stress in the age groups in which COPD is typically diagnosed (1, 6). However, we are not aware of previous investigations of work-related stress and the risk of COPD exacerbations.In this study, we examined the associations between job strain (the most widely studied conceptualisation of work-related stress) and severe COPD exacerbations using individual-level data from 10 prospective cohort studies from the Individual Participant Data Meta-analysis in Working Populations (IPD-Work) Consortium (7). Job strain is defined as a combination of high demands (excessive amounts of work) and low control (having little influence on what tasks to.