Body composition changes over 9 years in healthy elderly subjects and impact of physical activity

Background & aims: Age-related changes of body composition affect health status. This study aims at clarifying body composition changes in healthy elderly subjects, and evaluating the impact of physical activity on these changes. Methods: In 1999, 213 subjects >= 65 years recruited through advertisements underwent assessment of health state, energy expenditure by physical activity, body composition by bioimpedance analysis and body cell mass by total body potassium. In 2008,112 of them repeated these assessments with additional determination of Barthel index, Mini Mental State Examination and Geriatric Depression Score. Results: Lean tissues decreased in both genders (p < 0.05). Compared to subjects aged 65-74 years at baseline, those aged >= 75 years lost more body weight (men: -3.7 +/- 5.4 vs. 0.4 +/- 5.4 kg, women: -3.6 +/- 5.5 vs. 0.3 +/- 5.2 kg, both p < 0.05), and fat-free mass (men: -3.6 +/- 3.3 vs. -0.4 +/- 2.7 kg, women: -1.8 +/- 2.3 vs. -0.1 +/- 2.5 kg, both p < 0.05). Plotting of fat-free mass evolution against age at baseline showed an exponential loss of fat-free mass. Increased physical activity limited lean tissue loss in men but not in women. Conclusion: Loss of lean tissues occurs exponentially with aging. Further research should confirm these changes in subjects over 80 years. Increasing physical activity limits fat-free mass loss in men but not women. (C) 2011 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.