Hirsch C H, Fried L P, Harris T, Fitzpatrick A, Enright P, Schulz R
Department of Medicine, University of California, Davis, USA.
J Gerontol A Biol Sci Med Sci. 1997 Jul;52(4):M192-200. doi: 10.1093/gerona/52a.4.m192.
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.
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.
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.
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.
与年龄相关的肌肉性能变化在多大程度上代表正常衰老，以及在多大程度上是慢性疾病和生活方式的影响，目前尚不清楚。我们利用心血管健康研究（CHS）的基线数据，研究了四种性能指标——步速、定时起立试验（TCS）、握力和最大吸气压力（MIP）的相关因素。CHS是一项基于人群的研究，研究对象为65岁及以上人群的心脏病和中风危险因素。
我们分析了CHS的5201名参与者的数据。变量分为九类：个人特征、人体测量学、身体状况、报告的功能状态、主观健康、心理因素、症状、认知状态、习惯和生活方式以及常见疾病。使用逐步线性回归确定独立相关因素。
回归模型解释了17.7%-25.4%的观察到的变异性。尽管年龄与每个指标都显著相关，但它对变异性的解释很少（≤5.7%）。人体测量特征和身体状况解释了握力和MIP变异性的14.0%-17.4%，但仅解释了步速和TCS对数变异性的2.8%-12.9%。主观健康和心理因素解释了步速和TCS对数变异性的1.8%-9.4%，但对握力和MIP变异性的解释≤1.2%。常见疾病变量对每个指标变异性的解释≤1.3%。
在64岁以后，在大多数功能完好、居住在社区的老年人的大样本中，年龄对肌肉性能变异性的解释很少。与直接的力量测量相比，诸如步速等复杂指标与主观因素的关联更大。常见疾病对肌肉性能的影响出人意料地小。
