Rationale:~Chronic obstructive pulmonary disease (COPD) is defined as a preventable and treatable disease with significant extrapulmonary effects. Osteoporosis is recognized as one of these extrapulmonary consequences. It results in increased risk of fracture and thereby an increased morbidity and mortality. Nowadays it is believed that the patho-physiology of osteoporosis is multi-factorial. However, which factors are most important in patients with COPD is still not clear.~Objective:~The main objective is to study important factors in the patho-physiology of osteoporosis in patients with COPD. Therefore, we will study biological markers in plasma and urine and correlate them to markers of bone turnover and clinical data.~Study design:~The present study will be an observational, cross-sectional study.
The main objective is to study important factors in the patho-physiology of osteoporosis in patients with COPD. Therefore, the investigators will study biological markers in plasma and urine and correlate them to markers of bone turnover and clinical data.