@article {1485, title = {Correlates of performance-based measures of muscle function in the elderly: the Cardiovascular Health Study.}, journal = {J Gerontol A Biol Sci Med Sci}, volume = {52}, year = {1997}, month = {1997 Jul}, pages = {M192-200}, abstract = {

BACKGROUND: It is unknown how much age-related changes in muscle performance represent normal aging versus the effects of chronic disease and life style. We examined the correlates of four performance measures-gait speed, timed chair stands (TCS), grip strength, and maximal inspiratory pressure (MIP)-using baseline data from the Cardiovascular Health Study (CHS), a population-based study of risk factors for heart disease and stroke in persons > or = age 65.

METHODS: We analyzed data from the 5,201 CHS participants. Variables were arranged into nine categories: Personal Characteristics, Anthropometry, Physical Condition, Reported Functional Status, Subjective Health, Psychological Factors, Symptoms, Cognitive Status, Habits and Lifestyle, and Prevalent Disease. Independent correlates were identified using stepwise linear regression.

RESULTS: The regression models explained 17.7-25.4\% of the observed variability. Although age significantly correlated with each measure, it explained little of the variability (< or = 5.7\%). Anthropometric features plus physical condition explained 14.0-17.4\% of the variability for grip strength and MIP, but 2.8-12.9\% of the variability for gait speed and the log of TCS. Subjective health and psychological factors explained 1.8-9.4\% of the variability in gait speed and the log of TCS, but < or = 1.2\% of the variability in grip strength and MIP. Variables for prevalent disease explained < or = 1.3\% of the variability in each measure.

CONCLUSIONS: After age 64, age explained little of the variability in muscle performance in a large sample of mostly functionally intact, community-dwelling older persons. Complex measures such as gait speed were more associated with subjective factors than were direct measures of strength. Prevalent disease contributed surprisingly little to muscle performance.

}, keywords = {Aging, Anthropometry, Cardiovascular Physiological Phenomena, Female, Gait, Hand Strength, Health Status, Humans, Male, Middle Aged, Motor Activity, Muscles, Pressure, Regression Analysis, Respiration}, issn = {1079-5006}, author = {Hirsch, C H and Fried, L P and Harris, T and Fitzpatrick, A and Enright, P and Schulz, R} } @article {795, title = {Moderate renal impairment and risk of dementia among older adults: the Cardiovascular Health Cognition Study.}, journal = {J Am Soc Nephrol}, volume = {15}, year = {2004}, month = {2004 Jul}, pages = {1904-11}, abstract = {

Renal impairment is associated with an increased risk of carotid atherosclerosis and stroke, determinants of cognitive dysfunction and dementia. The purpose of this study was to determine whether moderate renal impairment is associated with incident dementia among community-dwelling older adults. Participants in the Cardiovascular Health Cognition Study without prevalent dementia (n = 3349) were included in the analysis. Incident dementia was confirmed through neurologic testing. Renal function at baseline was estimated by the inverse of serum creatinine (1/SCr); moderate renal impairment was defined as SCr > or = 1.3 mg/dl for women and > or = 1.5 mg/dl for men. Cox regression models were used to estimate the association of renal impairment with incident dementia. Because SCr is also a function of muscle mass, the authors determined whether the relationship between SCr and dementia was particularly strong among individuals without severe co-morbidity at baseline, as reflected by self-reported general health status. There were 477 incident dementia cases over a median 6 yr follow-up. After adjustment for potential confounders, moderate renal insufficiency was associated with a 37\% increased risk of dementia (95\% CI = 1.06 to 1.78). Similarly, a 0.5-unit decrement in 1/SCr (equivalent to an increase in SCr from 1.0 to 2.0 mg/dl) was associated with a 26\% increased risk (95\% CI = 1.02 to 1.60). These associations were present only among the 84\% of older adults who reported good-excellent health. Among those in good-excellent health, higher SCr was associated with vascular-type dementia but not Alzheimer-type dementia. Moderate renal impairment, reflected by a higher SCr, is associated with an excess risk of incident dementia among individuals in good-excellent health. Strategies to prevent or delay the onset of dementia in patients with moderate renal impairment are needed.

}, keywords = {Aged, Alzheimer Disease, Cardiovascular Diseases, Creatinine, Dementia, Dementia, Vascular, Female, Humans, Kidney, Kidney Diseases, Male, Muscles, Proportional Hazards Models}, issn = {1046-6673}, doi = {10.1097/01.asn.0000131529.60019.fa}, author = {Seliger, Stephen L and Siscovick, David S and Stehman-Breen, Catherine O and Gillen, Daniel L and Fitzpatrick, Annette and Bleyer, Anthony and Kuller, Lew H} }