Phenotypes of Muscle Loss in Smokers

PROJECT SUMMARY/ABSTRACT Chronic obstructive pulmonary disease (COPD) is a leading cause of death in the United States and worldwide. Decreased muscle mass is common in COPD and associates with lung disease severity, functional impairment, systemic inflammation, and all-cause mortality. Fat free mass index (FFMI), defined by the sum of whole-body

lean muscle and bone mineral content adjusted for height in meters squared, is an accepted surrogate marker of whole-body muscle mass in COPD. FFMI associates with lung function and is an independent predictor of mortality in individuals with COPD who have normal BMI. However, most studies evaluating FFMI in COPD are

cross-sectional and do not examine changes in FFMI over time. These longitudinal studies are critical to identify the clinical and molecular phenotype of individuals at greatest risk for disease morbidity and mortality. Additionally, most studies focused primarily on current and former smokers with airflow obstruction, defined by

a ratio of forced expiratory volume in 1 second to forced vital capacity (FEV1/FVC)