Post-Graduate Program in Health and Behavior, Catholic University of Pelotas, Pelotas, Rio Grande do Sul, Brazil.
Pennington Biomedical Research Center, LSU System, Baton Rouge, LA, USA.
Am J Clin Nutr. 2021 Jun 1;113(6):1679-1687. doi: 10.1093/ajcn/nqab029.
Calf circumference (CC) is used in geriatric studies as a simple and practical skeletal muscle (SM) marker for diagnosing low SM and sarcopenia. Currently applied CC cutoff points were developed in samples including older participants; values representative of the full adult lifespan are lacking.
We aimed to develop CC cutoff points and to identify relevant confounding factors from the large and diverse NHANES 1999-2006 population sample.
Demographic, anthropometric, and imaging data (DXA, appendicular lean mass) from the adult (age ≥18 y) NHANES sample were partitioned into subgroups according to sex, age, ethnicity, and race. Adults aged 18-39 y and BMI (in kg/m2) 18.5-24.9 were set as a reference population; CC cutoff points were derived at 1 and 2 SDs below the mean.
The sample included 17,789 participants, 51.3% males and 48.7% females, with respective ages (mean ± SD) of 43.3 ± 16.1 y and 45.5 ± 16.9 y. CC was strongly correlated with appendicular lean mass, r = 0.84 and 0.86 for males and females (both P < 0.001), respectively. Significant differences in mean CC were present across sex, ethnic, self-reported race, and BMI groups. Adjusting CC for adiposity using BMI revealed a decrease in CC beginning after the second decade in males and third decade in females. Rounded CC cutoff values for moderately and severely low CC were 34 cm and 32 cm (males), and 33 cm and 31 cm (females), respectively. Our findings support the use of BMI-adjusted CC values for participants outside the normal-weight BMI range (18-24.9).
This study defined CC values in a diverse population sample along with a BMI-adjustment approach that helps to remove the confounding effects of adiposity and thereby improves CC as a useful clinical estimate of SM mass.
小腿围（CC）在老年研究中被用作一种简单实用的骨骼肌（SM）标志物，用于诊断低 SM 和肌肉减少症。目前应用的 CC 截断值是在包括老年人在内的样本中开发的，缺乏代表完整成年期的数值。
我们旨在从 NHANES 1999-2006 大型多样本中开发 CC 截断值并确定相关混杂因素。
根据性别、年龄、族裔和种族将成人（年龄≥18 岁）NHANES 样本的人口统计学、人体测量学和影像学数据（DXA、四肢瘦体重）分为亚组。将 18-39 岁且 BMI（kg/m2）为 18.5-24.9 的成年人设定为参考人群；CC 截断值在平均值的 1 和 2 个标准差以下得出。
样本包括 17789 名参与者，51.3%为男性，48.7%为女性，年龄分别为（平均值±标准差）43.3±16.1 岁和 45.5±16.9 岁。CC 与四肢瘦体重密切相关，男性和女性的相关系数分别为 0.84 和 0.86（均 P<0.001）。男性和女性的 CC 均值在性别、族裔、自我报告种族和 BMI 组之间存在显著差异。使用 BMI 调整 CC 对肥胖的影响后，发现男性的 CC 从第二十年开始下降，女性的 CC 从第三十年开始下降。中度和重度低 CC 的 CC 截断值分别为男性 34 cm 和 32 cm，女性 33 cm 和 31 cm。我们的研究结果支持使用 BMI 调整的 CC 值来评估 BMI 范围（18-24.9）之外的参与者。
本研究在一个多样化的人群样本中定义了 CC 值，并提出了一种 BMI 调整方法，可以帮助消除肥胖的混杂影响，从而提高 CC 作为一种有用的临床 SM 质量估计值。
