title: Body composition changes over 9 years in healthy elderly subjects and impact of physical activity.
abstract: OBJECTIVE
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Clinical Nutrition, Switzerland.
authors.forename: Laurence
authors.initials: L
authors.lastname: Genton
authors.forename: Véronique L
authors.initials: VL
authors.lastname: Karsegard
authors.forename: Thierry
authors.initials: T
authors.lastname: Chevalley
authors.forename: Michel P
authors.initials: MP
authors.lastname: Kossovsky
authors.forename: Patrice
authors.initials: P
authors.lastname: Darmon
authors.forename: Claude
authors.initials: C
authors.lastname: Pichard
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D000375:Aging / Q000502:physiology*; D001823:Body Composition; D015992:Body Mass Index; D001835:Body Weight; D058620:Elder Nutritional Physiological Phenomena; D017097:Electric Impedance; D004734:Energy Metabolism; D005260:Female; D005500:Follow-Up Studies; D006304:Health Status; D006801:Humans; D008297:Male; D009043:Motor Activity; D011188:Potassium / Q000032:analysis*; D011446:Prospective Studies; D011795:Surveys and Questionnaires
chemical_list: D011188:Potassium