Three-Year Body Composition Variations in Elderly Subjects

Background: Cross sectional data show that aging is associated to sarcopenia. The aim of this study is to evaluate and compare longitudinal body composition changes between over-65y and over-75y old healthy subjects. The role of physical activity (PA) on body composition was also analyzed.

Method: Body composition was measured by DEXA (Hologic QDR-4500, Enhanced Whole Body 8.26a software version) at time 0 (T0) and 3 years later (T3). PA was evaluated by means of a standard questionnaire (1). Subjects were considered active if >10% of their energy expenditure was related to intense exercise (2). Statistical differences between T0 and T3 were analyzed by means of paired t-test.

Results: 191 volunteers were enrolled. Preliminary data at T0 and T3 are available for 120 of them (table). 59% of men and 49% of women were classified as physically active. Over-75 y women and men show a LBM loss, except active men who preserve their LBM.

	Men <75y T0	(n=41) T3	Men >75 T0	(n=23) T3	Women <75 T0	(n=19) T3	Women >75 T0	(n=16) T3
BW (kg)	75.3±10.7	74.9±9.9	72.5±4.1	72.7±7.3	67.4±12.6	69.2±13.7*	63.4±9.0	62.8±10.0
LBM (kg)	54.0±6.0	53.7±6.3	52.4±5.2	51.6±5.2*	40.9±4.7	41.0±4.9	39.0±4.0	38.4±4.4*
FM (kg)	18.9±5.5	18.7±5.3	17.6±3.9	18.6±4.4*	25.2±9.3	26.2±9.7	22.8±5.5	22.7±6.1
Mean±SD; T3 vs. T0 * P<0.01

Conclusions: In healthy aged people, despite a stable BW, LBM decreases after age 75 in both men and women. Physical exercise preserves LBM in over 75 y men, but not in women.

References: 1) Bernstein MS, 1999, Am J Public Health; 2) Ainsworth BE, 2000, Med Sci Sport Exercise