What is the prevalence of monoclonal gammopathy of undetermined significance (MGUS)?

Updated: Dec 29, 2019
  • Author: Suzanne R Fanning, DO; Chief Editor: Emmanuel C Besa, MD  more...
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MGUS represents two thirds of all plasma cell dyscrasias. The incidence increases with age. In a study of residents of Olmsted County, Minnesota, MGUS was found in 3.2% of persons 50 years of age or older, 5.3% of those 70 years of age or older, and 7.5% of those 85 years of age or older. [13]  Subsequently, however, Murray et al used mass spectrometry to retest the baseline samples in 300 of the Olmsted County residents who had a negative work-up for monoclonal proteins but later developed MGUS. This more sensitive assay revealed a prevalence of MGUS of 5.1% among persons 50 years of age and older. [14]

The prevalence of MGUS is higher in HIV-infected patients, although it decreased with the adoption of antiretroviral therapy. In a study of 383 French HIV-infected patients, 359 of whom were on antiretroviral therapy for a median duration of 105 months, there were 12 (3.1%) cases of MGUS, including five IgG kappa cases, 5 IgG lambda cases, one biclonal (2 IgG kappa) case, and one case with three monoclonal immunoglobulins (IgG kappa×2+IgG lambda). In all cases, the monoclonal immunoglobulin levels were low, and the level was below 1 g/l in all cases except two. No factors were found to be predictive of MGUS. [15]

In a prospective cohort study in Vietnam war veterans, the crude prevalence of overall MGUS was 7.1% (34 of 479) in veterans involved in the spraying of Agent Orange, versus 3.1% (15 of 479) in veterans who were not involved in herbicide spray missions. After adjustment for factors including age, race, and body mass index, this translated into a 2.4-fold increased risk for MGUS in exposed veterans (adjusted odds ratio, 2.37; 95% CI, 1.27-4.44; P = 0.007). [16]

In a study of firefighters involved in rescue and/or recovery work at the New York World Trade Center after the September 11, 2001 attack, Landdgren et al reported an age-standardized prevalence rate of MGUS and light-chain MGUS combined of 7.63 per 100 persons (95% CI, 5.45-9.81), which is 1.8-fold higher than rates from a reference population; the rate of light-chain MGUS was more than 3-fold higher than in the same reference population. Of the 781 firefighters studied, 16 had been diagnosed with multiple myeloma (7 of them with light-chain disease), at a median age of 57 years. [17]  

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