Peripheral Nerve Function Decline in an Aged Cohort

描述(申请人提供)：尽管周围神经功能不良在老年人中很常见，但随着年龄的增长，下降的速度尚不清楚。糖尿病和其他已知的神经病原因似乎很少解释随着年龄的增长而导致的神经功能丧失。我们对健康、老龄化和身体成分(Health ABC)队列中周围感觉和运动神经功能不良的患病率和危险因素进行了横断面流行病学研究。Health ABC的基线队列包括3075名男性和女性(42%的非裔美国人和52%的女性)。其中，1462名80-89岁的幸存者预计将接受第11年的随访检查。从2000-01到2007-08的纵向数据将有可能确定神经功能下降是否与2008-10年度预期的下肢残疾有关，以及这些联系是否由肌肉、骨密度和力量的变化所调节。我们的横断面研究表明，周围神经功能对他们的下肢功能和活动能力至关重要，并与肌肉力量和骨密度有关，表明周围神经在骨质疏松症和年龄相关性残疾中的重要性。Health ABC对众多潜在风险因素的分析表明，年龄本身仍然与周围神经功能较差密切相关，即使考虑到糖尿病等已确定的风险因素和亚临床周围动脉疾病和高加索种族等新的风险因素。到目前为止，还没有美国的研究报告这些方面的周围神经功能随着年龄的增长而下降的速度，或者确定它们是否先于下肢残疾。研究的具体目标是确定1)高加索人和非裔美国人老年人的周围感觉和运动神经功能在六年内下降，以及这些下降的危险因素(人口统计因素、维生素B12状况、葡萄糖代谢受损、亚临床周围动脉疾病)；以及2)周围感觉和运动神经功能下降的速度是否与两年后复发跌倒和自我报告步行能力下降有关。这项研究涉及NIA在其战略计划中确定的许多目标，包括预防残疾、了解与年龄有关的变化和评估种族差异。Health ABC的研究提供了一个独特且具有成本效益的机会，可以量化和确定感觉神经和运动神经功能下降的风险因素，并首次在一大批老年人中将这些下降与未来的残疾联系起来。

DESCRIPTION (provided by applicant): Although poor peripheral nerve function is common in older age, the rate of decline with aging is unknown. Diabetes and other known causes of neuropathy appear to account for very little of the loss of nerve function with advancing age. We conducted a cross-sectional epidemiologic study of the prevalence and risk factors or poor peripheral sensory and motor nerve function in the Health, Aging and Body Composition (Health ABC) cohort. The Health ABC baseline cohort included 3075 men and women (42 percent African-American and 52 percent women). Of these, 1462 survivors aged 80-89 years of age are expected for their eleventh year follow- up exam. Longitudinal data from 2000-01 to 2007-08 will make it possible to determine whether nerve function declines are related to prospective lower extremity disability in 2008-10 and whether or not these associations are mediated by changes in muscle, bone density, and strength. We have documented cross- sectionally that peripheral nerve function is critical to their lower extremity function and mobility and is associated with muscle strength and bone density, demonstrating the importance of the peripheral nerves in sarcopenia and age-related disability. Analyses of numerous potential risk factors in Health ABC have revealed that age itself remains strongly related to poorer peripheral nerve function, even when accounting for established risk factors such as diabetes, and novel risk factors such as subclinical peripheral arterial disease and Caucasian race. To date, no U.S. study has reported the rate of decline in these aspects of peripheral nerve function with aging or has determined whether they precede lower extremity disability. The specific aims are to determine 1) declines in peripheral sensory and motor nerve function over six years and risk factors for these declines (demographic factors, vitamin B12 status, impaired glucose metabolism, subclinical peripheral arterial disease) in Caucasian and African-American older adults; and 2) if the rate of decline in peripheral sensory and motor nerve function is prospectively related to rate of recurrent falls and a decline in self-reported walking ability over two years. This study addresses many goals of the NIA, defined in its strategic plan, including prevention of disability, understanding age-related change and evaluating ethnic disparities. The Health ABC Study provides a unique and cost-effective opportunity to quantify and identify risk factors for decline in sensory and motor nerve function and relate these declines to prospective disability for the first time among a large group of older adults.