Skeletal muscle mass independently predicts peak oxygen consumption and ventilatory response during exercise in noncachectic patients with chronic heart failure.

OBJECTIVES: We sought to assess whether skeletal muscle mass might be a predictor of peak oxygen consumption (Vo2) and relation of the ventilation to carbon dioxide production (VE/VCo2) slope in patients with chronic heart failure (CHF) independent of clinical conditions, neurohormonal activation and resting hemodynamics. BACKGROUND: A variety of abnormalities characterize skeletal muscle and contribute to exercise intolerance in patients with CHF. Skeletal muscle mass is a determinant of peak Vo2 both in healthy patients and in patients with CHF, but there are no reports on the independent predictive value of this parameter, which can be measured with great accuracy by whole-body dual energy X-ray absorptiometry (DEXA). The influence of skeletal muscle mass on VE/VCo2 slope is not known either. METHODS: We prospectively evaluated 120 consecutive noncachectic patients with CHF. Every patient underwent a cardiopulmonary exercise test, an echo-Doppler examination and an evaluation of neurohormonal activation and body composition as assessed by DEXA. RESULTS: At the univariate analysis, New York Heart Association (NYHA) class (p < 0.0001), age (p < 0.0001), male gender (p < 0.0001) and plasma renin (p < 0.0001) significantly related with peak Vo2. There was a significant correlation between lean mass and absolute peak Vo2 (r = 0.70, p < 0.0001) and VE/VCo2 slope (r = -0.27; p < 0.01). At the multivariate analysis, lean mass predicted peak Vo2 and VE/VCo2 slope independently of NYHA functional class, age, gender, neurohormonal activation and resting hemodynamics. CONCLUSIONS: Skeletal muscle mass is an independent predictor of peak Vo2 and VE/VCo2 slope in stable noncachectic patients with CHF. Future studies will determine whether an increase in skeletal muscle mass in the individual patient might result in an improvement in parameters of exercise capacity.

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

BACKGROUND: Body composition changes with age, with increases in fat mass and visceral fat and declines in skeletal muscle mass; lung function also declines with age. Age-related changes in body composition and fat distribution 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/m2) ranging from 19.8 to 37.1. Body composition was evaluated by using dual-energy X-ray absorptiometry and fat distribution was evaluated by using waist and hip circumferences, waist-to-hip ratio, and sagittal abdominal diameter (SAD). Spirometry was done in all subjects and the distance walked by each subject during a 6-min walking test was evaluated as was leg strength. RESULTS: A significant negative correlation was found between adiposity, fat distribution indexes, forced vital capacity (FVC), and forced expiratory volume in 1 s (FEV1). A positive correlation was found between fat-free mass and FVC. After adjustment for age, height, and weight, SAD still correlated 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 fat-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 lower in the lowest fat-free mass tertile (P < 0.01). Stepwise multiple regression analysis performed with use of lung function variables as the dependent variables and age, height, fat mass, fat-free mass, waist circumference, and SAD as the independent variables showed that 3 variables entered the regression for predicting FVC: height, which entered the regression first; SAD, which entered second; and fat-free mass, which entered third. Only 2 variables entered the regression for predicting FEV1: height, which entered the 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.

Homocysteine and life-style in the elderly.

Elevated homocysteine increases the risk of vascular diseases but little information is available about this issue in the elderly. The aim of this cross-sectional study was to evaluate the relationships between homocysteinemia and gender, anthropometric, and life-style characteristics in a community-dwelling elderly population (65 men and 120 women; 67-78 years). Basal plasma homocysteine levels were determined by High Performance Liquid Chromatography (HPLC). Clinical records, and nutritional and anthropometric variables were collected in all subjects. Body composition was evaluated in all subjects by Dual energy X-ray Absorptiometry (DXA). Thirty-three percent of women and 66% of men had hyper-homocysteinemia. In women, a positive correlation was present between homocysteinemia, age, diastolic blood pressure and plasmatic creatinine, and a negative correlation between homocysteine, fiber intake and folates. In males, there was a positive correlation between plasma homocysteine, age, and body mass index. Multiple regression analysis showed that fat-free mass, cigarette smoking, fiber intake, vitamin B6 and total kcal intake accounted for 18% of homocysteine variance in males (R2 = 0.18, p<0.05). Significantly higher homocysteine values were found in women with a history of cardiovascular disease than in those without (16.6 +/- 9.4 vs 13.8 +/- 4.4 micromol/L, p<0.05). Homocysteinemia was significantly higher in elderly men compared to women (16.7 +/- 4.7 vs 15.3 +/- 7.6; p<0.05). Gender differences in homocysteine disappeared after adjusting for fat-free mass. This study confirms the age-related increase in plasma homocysteine. Life-style characteristics seem to influence significantly homocysteine levels in the elderly. Our study shows that gender effects on homocysteine may be attributed to differences in body composition.