Radiographic Emphysema Predicts Low Bone Mineral Density in a Tobacco-exposed Cohort

Abstract

Rationale: Studies demonstrating an association between chronic obstructive pulmonary disease and low bone mineral density (BMD) implicate factors distinct from treatments and severity of lung disease in the pathogenesis of osteoporosis. Whereas emphysema has been independently associated with vascular disease and other comorbidities, its association with BMD has not been well studied. Objectives: We explored the associations of BMD with computed tomography (CT) measures of emphysema and other risk factors in current and former smokers. Methods: One hundred ninety subjects completed a CT scan, pulmonary function testing, questionnaires, and dual x-ray absorptiometry measurements of hip and lumbar spine BMD. Subjects were classified as having normal BMD, osteopenia, or osteoporosis. Demographic, physiologic, and radiographic characteristics were compared and the association of BMD with radiographic emphysema, airflow obstruction, and osteoporosis risk factors was assessed. Measurements and Main Results: No difference existed in age, tobacco exposure, oral steroid use, or physical activity across BMD categories. Both osteopenia and osteoporosis were associated with the presence of airflow obstruction, inhaled corticosteroid use, and female sex, and demonstrated a significant relationship with the presence of visual emphysema (P 5 0.0003). Quantitative emphysema, but not CTmeasured indices of airway wall thickness, was inversely associated with BMD. Visual emphysema alone was a significant predictor of osteopenia/osteoporosis (odds ratio 5 2.55; 95% confidence interval, 1.24-5.25) in a model including obstruction severity, age, sex, and inhaled and oral steroid use. Conclusions: Radiographic emphysema is a strong, independent predictor of low BMD in current and former smokers. This relationship suggests a common mechanistic link between emphysema and osteopenia/osteoporosis.

Is lung function associated with bone mineral density? Results from the Hertfordshire Cohort Study

“…COPD and bronchial asthma are risk factors for osteoporosis; these patients often display a loss of significant amounts of both cortical and trabecular bone [1][2][3][4][5][6][7][8][9]. These patients are also often treated with oral or inhaled glucocorticoids and this contributes to significant additional bone loss.…”

“…the prevalence of reduced bone density and vertebral fractures in patients with chronic obstructive pulmonary disease (COPD) is high [1][2][3][4]; furthermore case-control studies have confirmed reduced bone mineral density (BMD) in COPD patients compared with controls [5][6], even in those with milder disease [7] while in patients who have osteoporosis and spinal deformities, reduced pulmonary function is related to the severity of osteoporosis [9][10][11] in the same way that the worse the level of lung function in COPD patients, the greater the likelihood of low BMD [12].…”

Nutritional assessment and therapy in COPD: a European Respiratory Society statement

“…Additionally, systemic inflammation, the use of systemic corticosteroids and the high prevalence of vitamin D deficiency, which are frequently observed in more severe stages of COPD, unequivocally contribute to a further loss of bone and muscle mass [43,45]. Observational studies also suggest that emphysema represents a particular phenotype that is associated with musculoskeletal impairment but the underlying mechanisms remain unclear [46][47][48]. Bone tissue is continuously renewed throughout life.…”

C-X-C Motif Chemokine 13 (CXCL13) Is a Prognostic Biomarker of Idiopathic Pulmonary Fibrosis

“…Heparinized peripheral blood was obtained from consecutive patients with IPF (5,14,16,37), healthy volunteers, and subjects with cigarette smoking-attributable chronic obstructive pulmonary disease (COPD) and/or emphysema (henceforth collectively denoted as COPD) (38,39).…”

“…IPF acute exacerbations were defined by worsening hypoxemia and/or dyspnea during the preceding 30 days or less, with characteristic acute radiographic abnormalities, and no other attributable cause after thorough clinical evaluations (40). COPD was diagnosed by spirometry (38), and emphysema was detected and quantified by chest computed tomography scans (39). Subjects who were taking more than 10 mg prednisone per day, or other systemic immunosuppressants, were excluded from these analyses to avoid confounding effects of these medications on CXCL13 production (34).…”