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Obesity, race influence myeloma risk among those with monoclonal gammopathy of undetermined significance

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April 4, 2017


Obesity and black race increased the likelihood that monoclonal gammopathy of undetermined significance transformed into multiple myeloma, according to findings published in Journal of the National Cancer Institute.

Multiple myeloma is consistently preceded by monoclonal gammopathy of undetermined significance [MGUS] — a premalignant disorder characterized by an immunoglobulin spike in serum or urine without myeloma-related end-organ damage — or amyloidosis, which presents with an abnormal plasma cell burden similar to monoclonal gammopathy of undetermined significance,” Su-Hsin Chang, PhD, assistant professor in the division of public health sciences at St. Louis Veterans Affairs Medical Center, and colleagues wrote.

Risk factors for myeloma include older age, male sex, black race, obesity, family history and monoclonal gammopathy of undetermined significance.

“No studies have provided clear evidence of any modifiable risk factors that might be associated with progression of monoclonal gammopathy of undetermined significance to multiple myeloma,” Chang and colleagues wrote.

The researchers performed a population-based cohort study of 7,878 patients (64.1% white) diagnosed with MGUS between Oct. 1, 1999, and Dec. 31, 2009. More than two-thirds of the patients were overweight (39.8%) or obese (33.8%).

Chang and colleagues followed these patients through Aug. 6, 2013, and reviewed patient-level clinical data to verify diagnoses of multiple myeloma.

Three hundred twenty-nine patients (4.2%) progressed to multiple myeloma during follow-up, These included 72 normal-weight (3.5%; median follow-up, 61.9 months), 144 overweight (4.6%; median follow-up, 69.1 months) and 113 obese patients (4.3%; median follow-up, 70.6 months).

Multivariable analysis identified three factors associated with increased risk for transformation from MGUS to multiple myeloma: overweight (HR = 1.55; 95% CI, 1.16-2.06), obesity (HR = 1.98; 95% CI, 1.47-2.68) and black race (HR = 1.98; 95% CI, 1.55-2.54).

“Our results provide evidence that overweight and obesity after monoclonal gammopathy of undetermined significance diagnosis both increase the risk [for] progression of monoclonal gammopathy of undetermined significance to multiple myeloma,” the researchers wrote. “Further research is required to establish if this association is due to a faster rate of transformation. For black patients, close monitoring of the disease progression could lead to more timely diagnosis and treatment of multiple myeloma, which may improve survival.” – by Andy Polhamus

Disclosure: The researchers report no relevant financial disclosures.