Background

Lean muscle plays critical roles in physical functioning and metabolism. However, little is known regarding associations between muscle and mortality in adults.

Objective

The purpose was to evaluate associations between abdominal muscle quantity (area) and quality (density) with risk of all-cause mortality in a diverse cohort free of cardiovascular disease.

Design

Data were taken from the Abdominal Body Composition, Inflammation, and Cardiovascular Disease ancillary study of the Multi-Ethnic Study of Atherosclerosis prospective cohort study. Participants were adults (45–85 years) free of extant cardiovascular disease, and of Hispanic, African American, Chinese, or Caucasian descent. Of the original 6814 MESA participants, a random, representative sample (n = 1974) participated in the ancillary body composition study. Abdominal muscle area and density were measured from computed tomography scans spanning L2-L4. Muscle density was measured as attenuation in Hounsfield units, and area was quantified as cm². Gender-stratified cox proportional hazard models assessed the risk of all-cause mortality across gender-specific quartiles of muscle area and density adjusting for confounders, with area and density entered simultaneously.

Results

At baseline, the mean age for men (n = 946) and women (n = 955) was 61.5 and 62.5 years and median follow-up time was 10.6 and 10.9 years, respectively. Muscle density was inversely associated with mortality, with the highest quartile of density showing a 73% reduction in risk for men (HR = 0.27, 95% CI = 0.14–0.51; p-trend<0.001) and 57% reduction for women (HR = 0.43, 95% CI = 0.18–1.01; p-trend = 0.04) compared to the lowest quartile when adjusting for mortality risk factors, lifestyle, BMI and visceral fat. There was no association between muscle area and all-cause mortality for men (p-trend = 0.58) or women (p-trend = 0.47).

Conclusions

Greater abdominal muscle density, but not muscle area, is associated with markedly lower risk of all-cause mortality across a decade of follow up. Muscle quality may be a powerful predictor of mortality in community dwelling adults.

中文翻译：

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肌肉面积和密度以及全因死亡率的风险：动脉粥样硬化的多民族研究。

背景

瘦肌肉在身体机能和新陈代谢中起关键作用。但是，关于成人的肌肉与死亡率之间的关联知之甚少。

目的

目的是评估在无心血管疾病的不同人群中腹肌数量（面积）和质量（密度）与全因死亡率风险之间的关联。

设计

数据来自于多民族动脉粥样硬化前瞻性队列研究的腹部机体组成，炎症和心血管疾病辅助研究。参加者为成人（45-85岁），无现存的心血管疾病，无西班牙裔，非裔美国人，华裔或白种人血统。在最初的6814名MESA参与者中，有一个随机的代表性样本（n  = 1974）参加了辅助身体成分研究。腹部肌肉面积和密度是通过计算机断层扫描（横跨L2-L4）测量的。肌肉密度以Hounsfield单位衰减表示，面积量化为cm ²。性别分层的Cox比例风险模型评估了跨性别的四分位数的肌肉区域全因死亡的风险，并针对混杂因素调整了密度，同时输入了面积和密度。

结果

在基线时，男性（n  = 946）和女性（n  = 955）的平均年龄分别为61.5和62.5岁，中位随访时间分别为10.6和10.9岁。肌肉密度与死亡率成反比，密度最高的四分位数显示男性风险降低73％（HR = 0.27，95％CI = 0.14-0.51； p-趋势<0.001），女性降低57％（HR = 0.43，95％CI = 0.18–1.01； p趋势= 0.04），而调整死亡率风险因素，生活方式，BMI和内脏脂肪时的最低四分位数与之相比。男性（p趋势= 0.58）或女性（p趋势= 0.47）的肌肉面积与全因死亡率之间没有关联。

结论

在十年的随访中，腹肌密度更高而不是肌肉面积显着降低全因死亡率的风险。在社区居民中，肌肉质量可能是死亡率的有力预测指标。