BACKGROUND:In older adults, impaired control of standing balance in the lateral direction is associated with the increased risk of falling. Assessing the factors that contribute to impaired standing balance control may identify areas to address to reduce falls risk.AIM:To investigate the contributions of physiological factors to standing lateral balance control.METHODS:Two hundred twenty-two participants from the Pittsburgh site of the Health, Aging and Body Composition Study had lateral balance control assessed using a clinical sensory integration balance test (standing on level and foam surface with eyes open and closed) and a lateral center of pressure tracking test using visual feedback. The center of pressure was recorded from a force platform. Multiple linear regression models examined contributors of lateral control of balance performance, including concurrently measured tests of lower extremity sensation, knee extensor strength, executive function, and clinical balance tests. Models were adjusted for age, body mass index, and sex.RESULTS:Larger lateral sway during the sensory integration test performed on foam was associated with longer repeated chair stands time. During the lateral center of pressure tracking task, the error in tracking increased at higher frequencies; greater error was associated with worse executive function. The relationship between sway performance and physical and cognitive function differed between women and men.DISCUSSION:Contributors to control of lateral balance were task-dependent. Lateral standing performance on an unstable surface may be more dependent upon general lower extremity strength, whereas visual tracking performance may be more dependent upon cognitive factors.CONCLUSIONS:Lateral balance control in ambulatory older adults is associated with deficits in strength and executive function.

BACKGROUNDChange in body composition, specifically loss of fat-free mass and gain in fat mass, in older adults is a major pathway leading to the onset of functional decline and physical disability.OBJECTIVEThe objective was to determine the association of activity-related energy expenditure with change in body mass and composition among older men and women.DESIGNTotal energy expenditure (TEE) was assessed over 2 wk by using the doubly labeled water method in 302 community-dwelling older adults aged 70-82 y. Resting metabolic rate (RMR) was measured by using indirect calorimetry, and the thermic effect of meals was estimated at 10% of TEE. Activity energy expenditure (AEE) was calculated as [TEE(0.9) - RMR]. Total body mass, fat-free mass (FFM), and fat mass (FM) were assessed by dual-energy X-ray absorptiometry annually over a mean (+/-SD) of 4.9 +/- 1.3 y.RESULTSIn multivariate models adjusted for baseline age, smoking status, and race, men and women had a decline (in kg/y) in body mass (men: -0.34, 95% CI: -0.71, 0.02; women: -0.45, 95% CI: -0.71, -0.19) and FFM (men: -0.48, 95% CI: -0.67, -0.29; women: -0.14, 95% CI: -0.026, -0.03). No changes (in kg/y) were observed in FM (men: 0.14, 95% CI: -0.10, 0.38; women: -0.28, 95% CI: -0.49, -0.07). In men and women, higher AEE at baseline was associated with greater FFM. The average change in these outcomes (ie, slope), however, was similar across tertiles of AEE.CONCLUSIONSThese data suggest that accumulated energy expenditure from all physical activities is associated with greater FFM, but the effect does not alter the trajectory of FFM change in late life.

Clinical Pharmacology & Therapeutics (2007) 81, S10–S12. doi:10.1038/sj.clpt.6100173

CONTEXT:Significant symptoms of depression are common in the older community-dwelling population. Although depressive symptoms and disability may commonly occur in the same person, whether depressive symptoms contribute to subsequent functional decline has not been elucidated.OBJECTIVE:To determine whether depressive symptoms in older persons increase the risk of subsequent decline in physical function as measured by objective performance-based tests.DESIGN:A 4-year prospective cohort study.SETTING:The communities of Iowa and Washington counties, Iowa.PARTICIPANTS:A total of 1286 persons aged 71 years and older who completed a short battery of physical performance tests in 1988 and again 4 years later.MAIN OUTCOME MEASURES:Baseline depressive symptoms were assessed by the Center for Epidemiological Studies Depression Scale. Physical performance tests included an assessment of standing balance, a timed 2.4-m (8-ft) walk, and a timed test of 5 repetitions of rising from a chair and sitting down.RESULTS:After adjustment for baseline performance score, health status, and sociodemographic factors, increasing levels of depressive symptoms were predictive of greater decline in physical performance over 4 years (odds ratio for decline in those with depressed mood vs those without, 1.55; 95% confidence interval [CI], 1.02-2.34). Even among those at the high end of the functional spectrum, who reported no disability, the severity of depressive symptoms predicted subsequent decline in physical performance (odds ratio for decline, 1.03; 95% CI, 1.00-1.08).CONCLUSIONS:This study provides evidence that older persons who report depressive symptoms are at higher risk of subsequent physical decline. These results suggest that prevention or reduction of depressed mood could play a role in reducing functional decline in older persons.