EFFECTS OF FAT DISTRIBUTION ON LUNG VOLUME IN OBESE MEN

Abstract

Obesity decreases lung volume subdivisions, particularly end-expiratory lung volume (EELV). The effect of abdominal fat distribution (i.e., visceral and subcutaneous) on EELV has not been studied. PURPOSE: To investigate the effects of fat distribution on EELV, we studied body composition and EELV in 9 lean (18 ± 4% body fat) and 10 obese (38 ± 4% body fat) men. We hypothesized that abdominal fat distribution would better predict the change in EELV with mild-to-moderate obesity than overall percent body fat. METHODS: All subjects underwent spirometry and lung volume measurements, hydrostatic weighing, and abdominal fat distribution estimates based on MRI scans. Data were analyzed between groups by independent t-test and the relationship between variables was determined by regression analysis. RESULTS: Age and height were not different between groups. All body composition measurements were significantly different between the lean and obese men (p < 0.001). However, fat distribution was similar between the two groups. Spirometry data were not significantly different, nor was total lung capacity (TLC). On the other hand, EELV was significantly lower in the obese men (39 ± 6 vs. 46 ± 4%TLC, p < 0.01). While the correlation coefficient between percent body fat and EELV was significant (p < 0.05) at −0.56, the correlation between visceral fat (kg) and EELV was 00.70 (p < 0.001). CONCLUSION: It appears that visceral fat is a large contributor to low lung volume breathing in otherwise healthy mild-to-moderately obese men. Supported by the American Lung Association.