Monoclonal gammopathy of undetermined significance (MGUS) is a pre-malignant condition of multiple myeloma (MM). Evidence suggested old age, black race, male gender, and obesity as risk factors for MGUS development
however, whether they are associated with an increased risk of progression to MM among patients with MGUS is unclear. A systematic search of PUBMED and EMBASE for cohort studies investigating the association between age/race/gender/obesity and progression to MM. We used the Newcastle-Ottawa Scale (NOS) to assess the methodologic quality of the included studies. Summary risk ratios were calculated using random-effects models. We identified 24 publications, of which 17 articles were included in the main analyses. Overall, the quality of the studies was fair (mean NOS = 5.5). Our meta-analyses showed that old age was positively associated with the risk of the MGUS-MM progression (risk ratio: 2.38
95% confidence interval [CI] 1.59-3.57), while race was not statistically significantly associated with the risk (blacks vs whites: 1.09
95% CI: 0.77-1.54). Males had a lower risk of MGUS-MM progression, compared to females (risk ratio: 0.70
95% CI 0.50-1.0
P-value = .048). High body mass index was significantly associated with an increased risk of MGUS-MM progression (risk ratio: 1.32
95% CI 1.12-1.57). Based on extant research, old age, female sex, and obesity may be implicated in MGUS-MM progression. However, several studies which found an insignificant association between age/gender and progression did not report the risk estimates. Publication bias exists and our risk estimates may be overestimated. More studies are warranted to confirm our findings.