BACKGROUND Obesity is a globally increasing health problem that impacts multiple organ systems and a potentially modifiable risk factor for many diseases. Obesity has a significant impact on lung function and is strongly linked to the pathophysiology that contributes to lung diseases. On the other hand, reports have emerged that obesity is associated with a better prognosis than for normal weight individuals in some lung diseases, including pneumonia, acute lung injury/acute respiratory distress syndrome, chronic obstructive pulmonary disease, and lung cancer. The lesser mortality and better prognosis in patients with obesity is known as obesity paradox. While obesity paradox is both recognized and disputed in epidemiological studies, recent research has suggested possible mechanisms. SUMMARY In this review, we attempted to explain and summarize these factors and mechanisms, including immune response, pulmonary fibrosis, lung function, microbiota, fat and muscle reserves, which are significantly altered by obesity and may contribute to the obesity paradox in lung diseases. We also discuss contrary literature that attributes the "obesity paradox" to confounding. KEY MESSAGES The review will illustrate the possible role of obesity in the prognosis or course of lung diseases, leading to a better understanding of the obesity paradox and provide hints for further basic and clinical research in lung diseases.

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肺部疾病中的肥胖悖论：如何解释？

背景技术肥胖是全球日益严重的健康问题，其影响多个器官系统并且是许多疾病的潜在可改变的危险因素。肥胖对肺功能有重大影响，并且与导致肺部疾病的病理生理学密切相关。另一方面，有报道称，肥胖与某些肺部疾病（包括肺炎、急性肺损伤/急性呼吸窘迫综合征、慢性阻塞性肺病和肺癌）的预后优于正常体重者。肥胖患者死亡率较低且预后较好，这被称为肥胖悖论。虽然肥胖悖论在流行病学研究中既得到认可，也存在争议，但最近的研究提出了可能的机制。总结在这篇综述中，我们试图解释和总结这些因素和机制，包括免疫反应、肺纤维化、肺功能、微生物群、脂肪和肌肉储备，这些因素和机制会因肥胖而显着改变，并可能导致肺部疾病中的肥胖悖论。我们还讨论了将“肥胖悖论”归因于混杂因素的相反文献。关键信息 该综述将阐明肥胖在肺部疾病的预后或病程中可能发挥的作用，从而更好地理解肥胖悖论，并为肺部疾病的进一步基础和临床研究提供线索。