Relation between body composition, fat distribution, and lung function in elderly men

Background: Body composition changes with age, with increases in fat mass a nd visceral fat and declines in skeletal muscle mass; lung function also de clines with age. Age-related changes in body composition and fat distributi on may be associated with the pulmonary impairment observed in the elderly. Objective: Our goal was to evaluate the relations between body composition, fat distribution, and lung function in elderly men. Design: We studied 97 men aged 67-78 y with body mass indexes (BMIs; in kg/ m(2)) ranging from 19.8 to 37.1. Body composition was evaluated by using du al-energy X-ray absorptiometry and fat distribution was evaluated by using waist and hip circumferences, waist-to-hip ratio, and sagittal abdominal di ameter (SAD). Spirometry was done in all subjects and the distance walked b y each subject during a 6-min walking test was evaluated as was leg strengt h. Results: A significant negative correlation was found between adiposity, fa t distribution indexes, forced vital capacity (FVC), and forced expiratory volume in 1 s (FEV1). A positive correlation was found between fat-free mas s and FVC. After adjustment for age, height, and weight, SAD still correlat ed negatively with FVC and FEV1 (r = -0.367 and -0.348, respectively; P < 0 .01), whereas percentage body fat and fat mass correlated negatively and fa t-free mass correlated positively with FVC (r = -0.313, -0.323, and 0.299, respectively; all P < 0.01). After the sample was subdivided by tertile of fat-free mass adjusted for age and BMI, FVC and FEV1 were significantly low er in the lowest fat-free mass tertile (P < 0.01). Stepwise multiple regres sion analysis performed with use of lung function variables as the dependen t variables and age, height, fat mass, fat-free mass, waist circumference, and SAD as the independent variables showed that 3 variables entered the re gression for predicting FVC: height, which entered the regression first; SA D, which entered second; and fat-free mass, which entered third. Only 2 var iables entered the regression for predicting FEV1: height, which entered th e regression first, and SAD, which entered second. Conclusion: Our cross-sectional data show a significant association between body composition, fat distribution, and lung function in elderly men.