The Relationship between a Decrease in Fat Mass and Serum Levels of TNF-α in Patients with Chronic Obstructive Pulmonnary Disease

To investigate the relationship between malnutrition and TNF-alpha levels in patients with chronic obstructive pulmonary disease (COPD), we measured concentrations of TNF-alpha in serum from fifty four patients with stable COPD. The patients were divided into three groups, according to ideal body weight (IBW): group A, %IBW > or = 90; group B, 90 > %IBW > or = 80; group C, %IBW < 80. Serum TNF-alpha levels in group C were significantly higher than in group A (mean +/- SD; 3.00 +/- 0.43 pg/ml and 2.25 +/- 0.29 pg/ml, respectively, p < 0.0001), group B (2.41 +/- 0.47 pg/ml, p < 0.001), and healthy controls (2.33 +/- 0.30 pg/ml, p < 0.001) who were age- and %IBW-matched with patients in group C. Sixteen patients with COPD underwent body composition analysis by dual energy X-ray absorptiometry. Serum TNF-alpha levels in patients with COPD significantly correlated with fat mass (r = -0.67, p < 0.001). No association was observed between lean mass and serum TNF-alpha levels. These data suggest that TNF-alpha is involved with malnutrition in patients with COPD, and that TNF-alpha may cause a decrease in fat mass in patients with COPD.