Skeletal muscle, subcutaneous fat, and clinical outcomes in smokers.

The purpose of this investigation is to validate and apply computed tomographic measures of body composition in smokers.  Image based assessments of the pectoralis and erector spinae muscles and adjacent subcutaneous fat as well as diaphragm muscle thickness will be explored in two large observational studies, COPDGene and ECLIPSE.  Cross sectional and longitudinal associations with clinically relevant outcomes will be explored.

Raúl San José Estépar

Dr. Raúl San José Estépar

Associate Professor of Radiology in Harvard Medical School
Lead Investigator at Brigham and Women's Hospital
Raúl is Associate Professor of Radiology at Harvard Medical School and a Research Associate at Brigham and Women's Hospital. He is the co-director of the Applied Chest Imaging Laboratory (ACIL).
 
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Diaz AA, Zhou L, Young TP, McDonald M-L, Harmouche R, Ross JC, Estepar RSJ, Wouters EFM, Coxson HO, MacNee W, et al. Chest CT measures of muscle and adipose tissue in COPD: gender-based differences in content and in relationships with blood biomarkers. Acad Radiol. 2014;21 (10) :1255-61.Abstract

RATIONALE AND OBJECTIVES: Computed tomography (CT) of the chest can be used to assess pectoralis muscle area (PMA) and subcutaneous adipose tissue (SAT) area. Adipose tissue content is associated with inflammatory mediators in chronic obstructive pulmonary disease (COPD) subjects. Based on gender differences in body composition, we aimed to assess the hypothesis that in subjects with COPD, the relationships between PMA, SAT, and blood biomarkers of inflammation differ by gender. MATERIALS AND METHODS: We compared chest CT measures of PMA and SAT on a single slice at aortic arch and supraesternal notch levels from 73 subjects (28 women) with COPD between genders. The relationships of PMA and SAT area to biomarkers were assessed using within-gender regression models. RESULTS: Women had a lesser PMA and a greater SAT area than men (difference range for PMA, 13.3-22.8 cm²; for SAT, 11.8-12.4 cm²; P < .05 for all comparisons) at both anatomic levels. These differences in PMA and SAT remained significant after adjustment for age and body mass index. Within-gender regression models adjusted for age showed that SAT was directly associated with C-reactive protein (for aortic arch level, P = .04) and fibrinogen (for both anatomic locations, P = .003) only in women, whereas PMA was not associated with any biomarkers in either gender. CONCLUSIONS: It appears that in subjects with COPD, there are gender-based differences in the relationships between subcutaneous adipose tissue and inflammatory biomarkers.