Heart Institute (InCor), University of São Paulo Medical School, São Paulo/SP, Brazil.
Department of Physical Education and Sport Sciences, Faculty of Education and Health Sciences, University of Limerick, Limerick, Ireland.
Curr Opin Clin Nutr Metab Care. 2022 Jan 1;25(1):1-6. doi: 10.1097/MCO.0000000000000802.
Obesity has shown a protective effect on mortality in older adults, also known as the obesity paradox, but there are still controversies about this relationship.
Recent studies have shown a J or U-shaped relationship between BMI and mortality, wherein an optimal range is described between 22 and 37 kg/m2 depending on the condition. Many mechanisms can explain this protective effect of higher BMI, fat/muscle mass storage, more aggressive treatment in obese individuals, loss of bone mineral content and selection bias. However, BMI must be used with caution due to its limitations to determine body composition and fat distribution.
Although BMI is an easy tool to evaluate obesity, its protective effect may be present to certain extend, from normal range to class I obesity (BMI 30-34.9 kg/m2), but then it becomes detrimental. Skeletal muscle mass and muscle function associated with adipose tissue assessment can add valuable information in the risk stratification. Further studies should be performed prospectively, adjust BMI for cofounding variable and consider other elderly subpopulations. To promote healthy ageing, excessive fat mass should be avoided and maintenance or improvement of skeletal muscle mass and muscle function should be stimulated in older adults.
肥胖与老年人死亡率呈负相关，即肥胖悖论，但这种关系仍存在争议。
最近的研究表明，BMI 与死亡率之间呈 J 形或 U 形关系，在不同的情况下，最佳范围描述为 22 至 37kg/m2 之间。许多机制可以解释较高 BMI 的这种保护作用，包括脂肪/肌肉质量的储存、肥胖个体更积极的治疗、骨矿物质含量的丧失和选择偏差。然而，由于 BMI 存在局限性，无法确定身体成分和脂肪分布，因此必须谨慎使用。
虽然 BMI 是评估肥胖的一种简单工具，但它的保护作用可能在一定程度上存在，从正常范围到 I 级肥胖（BMI 为 30-34.9kg/m2），但之后就会产生不利影响。与脂肪组织评估相关的骨骼肌质量和肌肉功能可以为风险分层提供有价值的信息。应进行前瞻性研究，调整 BMI 以控制混杂变量，并考虑其他老年亚群。为促进健康老龄化，应避免过多的脂肪质量，并刺激老年人维持或改善骨骼肌质量和肌肉功能。
