Monoclonal gammopathy (MG) represents a spectrum of related diseases, with monoclonal gammopathy of undetermined significance (MGUS) being the most prevalent. MGUS invariably precedes every case of smoldering multiple myeloma (SMM) and clinical multiple myeloma (MM). A risk of progression from MGUS to MM is about 1% per year [1], whereas for patients with SMM, it can reach up to 63% in 2 years [2]. While the association between MG and metabolic conditions has been recognized, the precise etiopathogenic mechanisms remain elusive.

High body mass index is reported as a risk factor for MGUS and MM. Obesity may be recognized as a significant factor in the progression from MGUS to MM and higher mortality in MM [3]. Conversely, obese individuals may have improved progression free survival and overall survival in relapsed/refractory MM [4]. Yet, body mass index did not affect mortality in patients who underwent hematopoietic stem cell transplantation for MM [5].

单克隆丙种球蛋白病 (MG) 是一系列相关疾病的代表，其中意义未明的单克隆丙种球蛋白病 (MGUS) 是最常见的。 MGUS 总是出现在每一个冒烟型多发性骨髓瘤 (SMM) 和临床多发性骨髓瘤 (MM) 病例之前。从 MGUS 进展为 MM 的风险约为每年 1% [1]，而对于 SMM 患者，该风险在 2 年内可达到 63% [2]。虽然重症肌无力与代谢状况之间的关联已被认识，但精确的发病机制仍然难以捉摸。

据报道，高体重指数是 MGUS 和 MM 的危险因素。肥胖可能被认为是从 MGUS 进展为 MM 以及 MM 死亡率较高的一个重要因素 [3]。相反，肥胖个体可能会改善复发/难治性 MM 的无进展生存期和总生存期 [4]。然而，体重指数并不影响接受造血干细胞移植治疗MM的患者的死亡率[5]。