D. Mitchell*, M. N. Haan**, F. M. Steinberg***, M. Visser****

* Department of Epidemiology and Preventive Medicine, University of California, Davis, ** University of Michigan, School of Public Health, Dept of Epidemiology, Ann Arbor, MI 48109, *** Department of Nutrition, University of California, Davis, **** Institute for Research in Extramural Medicine (EMGO), Vrije University Medical Center, Amsterdam, NL. Correspondence to: Diane Mitchell Ph.D., Center for Health and the Environment, 3792 Old Davis Road, Davis, CA 95616 , USA.
Phone: (530) 752 1810. Fax : (530) 752 3500. E-mail: dcmitchell@ucdavis.edu

Abstract: BACKGROUND: Controversy exists regarding the relative contribution of diet and exercise to body composition. Few studies have examined these associations in the elderly, where changes occur in the body fat to muscle ratio. OBJECTIVE: The primary objective of this paper is to determine whether energy intake or physical activity are associated with body composition. Secondly, to investigate whether specific macronutrients are associated with fat or lean tissue. DESIGN: Data (n= 1404) for this cross-sectional analysis were collected from a population-based sub-sample of elderly enrollees in the Cardiovascular Health Study (CHS). Dietary intake and physical activity were assessed by questionnaires. Body composition was measured by Dual Energy X-ray Absorptiometry (DEXA). Linear regression models were used to assess the associations of diet and activity with body composition. RESULTS: Total energy intake was not associated with any of the body composition measures. Higher dietary saturated fat was associated with higher percent body mass as fat and trunk fat in both sexes (p<0.01), and in men other dietary fats were associated with body fat. In women, distance walked was inversely associated with fat masses even after adjustment for pace of walking. In both sexes, faster pace of walking was associated with lower body and fat mass (p<0.01). Lean muscle mass was not associated with physical activity or dietary intakes. CONCLUSION: Physical activity and dietary fat intake in this the elderly population were more closely associated with body fat mass than was total energy intake.

Key words: Aging, diet, elderly, energy intake, physical activity, dietary macronutrients, body composition, DEXA, nutrition.