Duchowny Kate A, Peterson Mark D, Clarke Philippa J
Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, Michigan.
Department of Physical Medicine and Rehabilitation, University of Michigan, Ann Arbor, Michigan.
Am J Prev Med. 2017 Jul;53(1):63-69. doi: 10.1016/j.amepre.2016.12.022. Epub 2017 Feb 9.
Muscle weakness is an important indicator of disability, chronic disease, and early mortality. Grip strength is a simple, cost-effective measure of overall muscle strength. The Foundation of the National Institutes of Health recently proposed sex-specific grip strength cut points for clinical muscle weakness. However, these criteria were established using non-nationally representative data. This study used nationally representative data on Americans aged ≥65 years to identify race- and sex-specific cut points for clinical muscle weakness and quantify prevalence among older blacks and whites by sex.
Classification and Regression Tree models were used to identify cut points based on individual-level grip strength associated with slow gait speed (<0.8 m/second) among 7,688 individuals (57% female; 8% black; mean age, 74.6 [SD=6.79] years) from the 2010/2012 Health and Retirement Study during January-April 2016. Identified cut points were then used to quantify the prevalence of weakness by race/sex subgroup.
Fifty-five percent of men (maximum grip strength <39 kg) and 47% of women (maximum grip strength <22 kg) were classified as weak. Higher cut points were identified for black men (maximum grip strength <40 kg) and women (maximum grip strength <31 kg), and the prevalence of weakness (57% and 88%, respectively) was higher compared with whites. Fifty-five percent of individuals had slow gait speed (<0.8 m/second).
Prevalence of weakness was substantially higher than previous reports, underscoring the importance of using population-level data to identify individuals at greatest risk for adverse health outcomes. This is the first study to establish cut points for muscle weakness in a nationally representative sample by race and sex.
肌肉无力是残疾、慢性病和过早死亡的重要指标。握力是一种简单且经济高效的整体肌肉力量测量方法。美国国立卫生研究院基金会最近提出了针对临床肌肉无力的性别特异性握力切点。然而，这些标准是使用非全国代表性数据制定的。本研究使用了针对65岁及以上美国人的全国代表性数据，以确定临床肌肉无力的种族和性别特异性切点，并按性别量化老年黑人和白人中的患病率。
在2016年1月至4月期间，使用分类与回归树模型，基于来自2010/2012健康与退休研究的7688名个体（57%为女性；8%为黑人；平均年龄74.6[标准差=6.79]岁）中与慢步态速度（<0.8米/秒）相关的个体水平握力来确定切点。然后使用确定的切点按种族/性别亚组量化无力的患病率。
55%的男性（最大握力<39千克）和47%的女性（最大握力<22千克）被归类为无力。确定黑人男性（最大握力<40千克）和女性（最大握力<31千克）的切点更高，与白人相比，无力的患病率（分别为57%和88%）更高。55%的个体有慢步态速度（<0.8米/秒）。
无力的患病率远高于先前报告，强调了使用人群水平数据来识别健康不良后果风险最高个体的重要性。这是第一项在全国代表性样本中按种族和性别建立肌肉无力切点的研究。
