Aim s Myocardial infarction is nominally the most important co-morbidity in patients with chronic obstructive pulmonary disease, and the one with the greatest potential for treatment and prevention to improve the overall prognosis of chronic obstructive pulmonary disease patients. We assessed the extent of myocardial infarction and other co-morbidities in individuals with chronic obstructive pulmonary disease in the general population. Methods and resultsWe used individual participant data for the entire Danish population from 1980 through 2006, comprising 140 million person-years of follow-up. We used information from four national Danish registries with 100 follow-up and detected ever-diagnosed chronic obstructive pulmonary disease (n 313 958) and incident cases of a first myocardial infarction (n 422 344), lung cancer (n 116 629), hip fracture (n 53 756), depression (n 93 038), and diabetes mellitus (n 292 228). Multivariate adjusted hazard ratios for life-time association with ever-diagnosed chronic obstructive pulmonary disease were 1.26 (95 CI 1.251.27) for myocardial infarction, 2.05 (2.032.08) for lung cancer, 2.12 (2.072.17) for hip fracture, 1.74 (1.701.77) for depression, and 1.21 (1.201.23) for diabetes mellitus, compared with controls; these risk estimates were highest in women and the youngest age groups. Before the first hospitalization with chronic obstructive pulmonary disease, multivariate adjusted odds ratios were 1.47 (1.441.49) for myocardial infarction, 3.68 (3.523.84) for lung cancer, 1.16 (1.131.18) for hip fracture, 1.88 (1.801.96) for depression, and 1.16 (1.131.18) for diabetes mellitus, compared with matched controls. Corresponding values after a chronic obstructive pulmonary disease hospitalization were 0.74 (0.730.76), 1.48 (1.451.51), 1.23 (1.201.27), 1.21 (1.181.24), and 0.83 (0.810.85), respectively.ConclusionChronic obstructive pulmonary disease was associated with higher rates of myocardial infarction, lung cancer, diabetes, hip fracture, and depression, but the strength of these associations was modified after a first admission for chronic obstructive pulmonary disease. These associations may be related to common genetic and/or lifestyle/ environmental risk factors, and therefore these factors are likely to have an adverse health impact rather than chronic obstructive pulmonary disease per se.