[Relationship between diaphragm weight and body composition].

To study the relationship between diaphragm weight and body composition, we measured fat body mass and lean body mass by dual-energy X-ray absorptiometry (XR-26, Norland), and weighed the diaphragms of patients at autopsy. The subjects were 22 patients with various diseases (13 men and 9 women, aged 72.6 +/- 9.5 years). In 8 of the patients, respiratory muscle strength was assessed with maximal pressure at the mouth. The diaphragm weight was 185.2 +/- 58.2 g and it correlated significantly with lean body mass (r = 0.77, r = 0.73, p < 0.01). Maximal inspiratory pressure at TLC correlated significantly with diaphragm weight. These results show that respiratory muscle strength is related to diaphragm weight and that analysis of body composition may be useful in assessing changes in the mass of the diaphragm.