Thorax 1987;42:962-966 Vertebral compression fractures and mineral metabolism in chronic obstructive lung disease

Chronic obstructive lung disease has been reported as a cause of osteoporosis, though whether this association is due to the disease itself or to corticosteroid treatment has not been elucidated. We studied 44 male patients with chronic obstructive lung disease (mean (SD) FEVy 39% (14%) of predicted normal) who were not having long term corticosteroids. No differences in a vertebral deformity score or in metacarpal index were found between them and a control group of similar age. Indices of bone formation (serum osteocalcin) and bone resorption (urinary hydroxyproline) were normal and parathyroid hormone and 1,25-dihydroxyvitamin D were also normal. Serum 25-hydroxyvitamin D was decreased, indicating depleted vitamin D. Calcitonin concentrations were higher in the patient than in the control group of the same age. There was no increase in the prevalence of osteoporosis in patients with chronic obstructive lung disease who had not received long term corticosteroid treatment. Increased concentrations of calcitonin may protect the skeleton from the detrimental effect of hypovitaminosis D. Osteoporosis has been reported in patients with chronic obstructive lung disease, but this association is not well established. Most studies, however, have been performed in asthmatic patients rather than in patients with chronic obstructive bronchitis or emphysema, and have usually focused on the influence of corticosteroid administration, an accepted factor in the pathogenesis of osteoporosis. Other factors present in patients with chronic obstructive lung disease may be risk factors for osteoporosis. Important among them may be: low levels of physical activity, low sunlight exposure, a history of smoking, a history of alcohol consumption (which is known to be increased in chronic obstructive lung disease), and administration of calciuretic agents such as frusemide.'A Whether patients with chronic obstructive lung disease develop osteoporosis in the absence of steroid treatment is not known. Recent studies in asthmatic patients5 found a decreased bone mass only in patients treated with corticosteroids, contradicting some older reports.67 Address for reprint requests: Professor J Gonzalez Macias, Departamento de Medicina Interna, Hospital Nacional Marques de Valdecilla, 39008 Santander, Spain. Accepted 3 August 1987 This study was undertaken to determine whether the prevalence of osteoporosis was increased in men with chronic obstructive lung disease who had not had long term corticosteroid treatment and to study the activity of hormonal systems regulating bone metabolism in those patients.