Ralston Maximilian R, McCreath Gordan, Lees Zoe J, Salt Ian P, Sim Malcolm A B, Watson Malcolm J, Freeman Dilys J
School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow, UK.
Academic Unit of Anaesthesia, Critical Care & Perioperative Medicine, University of Glasgow, Glasgow, UK.
BJA Open. 2025 Mar 27;14:100391. doi: 10.1016/j.bjao.2025.100391. eCollection 2025 Jun.
Obesity is a worldwide health crisis and poses significant challenges in critical care. Many studies suggest an 'obesity paradox', in which obesity, defined by body mass index (BMI), is associated with better outcomes. However, the inability of BMI to discriminate between fat and muscle or between visceral adipose tissue and subcutaneous adipose tissue, limits its prediction of metabolic ill health. We suggest that the 'obesity paradox' may be more reflective of the limitations of BMI than the protective effect of obesity. We explore the biological processes leading to visceral fat accumulation, and the evidence linking it to outcomes in critical illness. In the 'spillover' hypothesis of adipose tissue expansion, caloric excess and impaired expansion of storage capacity in the subcutaneous adipose tissue lead to accumulation of visceral adipose tissue. This is associated with a chronic inflammatory state, which is integral to the link between visceral adiposity, type 2 diabetes mellitus, and ischaemic heart disease. We review the current evidence on visceral adiposity and critical illness outcomes. In COVID-19, increased visceral adipose tissue, irrespective of BMI, is associated with more severe disease. This is mirrored in acute pancreatitis, suggesting visceral adiposity is linked to poorer outcomes in some hyperinflammatory conditions. We suggest that visceral adiposity's chronic inflammatory state may potentiate acute inflammation in conditions such as COVID-19 and acute pancreatitis. Further work is required to investigate other critical illnesses, especially sepsis and acute respiratory distress syndrome, in which current evidence is scarce. This may give further insights into pathophysiology and inform tailored treatment and nutrition strategies based on body fat distribution.
肥胖是一场全球性的健康危机，在重症监护领域带来了重大挑战。许多研究表明存在“肥胖悖论”，即根据体重指数（BMI）定义的肥胖与更好的预后相关。然而，BMI无法区分脂肪和肌肉，也无法区分内脏脂肪组织和皮下脂肪组织，这限制了其对代谢性健康问题的预测能力。我们认为，“肥胖悖论”可能更多地反映了BMI的局限性，而非肥胖的保护作用。我们探讨了导致内脏脂肪堆积的生物学过程，以及将其与危重病预后相关联的证据。在脂肪组织扩张的“溢出”假说中，热量过剩以及皮下脂肪组织储存能力扩张受损会导致内脏脂肪组织堆积。这与一种慢性炎症状态相关，而这种慢性炎症状态是内脏肥胖、2型糖尿病和缺血性心脏病之间联系的一个组成部分。我们回顾了目前关于内脏肥胖与危重病预后的证据。在新冠肺炎中，无论BMI如何，内脏脂肪组织增加都与更严重的疾病相关。急性胰腺炎中也有类似情况，这表明内脏肥胖与某些高炎症状态下的较差预后有关。我们认为，内脏肥胖的慢性炎症状态可能会在新冠肺炎和急性胰腺炎等病症中加剧急性炎症。还需要进一步开展研究，以调查其他危重病，尤其是脓毒症和急性呼吸窘迫综合征，目前在这些病症方面的证据还很匮乏。这可能会进一步深入了解病理生理学，并为基于身体脂肪分布的量身定制的治疗和营养策略提供依据。
