Monoclonal Gammopathy of Undetermined Significance Examined in Deployed and Never Deployed Service Members

A prevalence of 6-fold higher-than-average reported in the National Health and Nutrition Examination Survey Study of light-chain (LC) monoclonal gammopathy of undetermined significance (MGUS) has been shown in US service members (SMs), but does not appear to be linked to burn pit exposure, according to a study presented at the 66th ASH Annual Meeting & Exposition held in San Diego, CA.¹

Researchers from the Myeloma Division at the University of Miami, Sylvester Comprehensive Cancer Center, in Miami, FL, and Walter Reed National Military Medical Center, in Chevy Chase, MD, obtained serum samples and clinical data on 1589 people in the Armed Forces Health Surveillance Division epidemiologic health registry and biorepository after institutional review board exemptions.

The researchers included a cohort of 534 US SMs who deployed to Iraq (Dep-Iraq) between January 1, 2005, and June 30, 2007, and who reported burn pit exposure on their post-deployment health assessment form (Dep-Iraq), who were then matched 1:1 to 534 SMs deployed to Germany (Dep-DEU) during the same period, with no Southwest Asia deployment or toxic exposures. Additionally, a third group of 521 SMs who never deployed (Non-Dep) were included in the analysis.

The overall prevalence of MGUS (IFE-positive monoclonal protein) in the entire cohort was 4.7% (95% CI, 3.7%-5.9%), while the prevalence of free LC MGUS (abnormal sFLC ratio) was 1.1% (95% CI, 0.7%-1.8%), resulting in a combined prevalence of MGUS and LC-MGUS of 5.9% (95% CI, 4.7%-7.1%). Among the deployed cohort (N=1068), the prevalence of MGUS was 4.5% (95% CI, 3.3%-5.9%), compared with 5.2% (95% CI, 3.4%-7.5%) in the nondeployed cohort (N=521), with no significant difference (P=.31).

However, a notable difference was observed in the prevalence of LC-MGUS. The deployed cohort demonstrated a significantly higher prevalence of LC-MGUS (1.6%; 95% CI, 0.9%-2.5%) compared with the nondeployed cohort (0.2%; 95% CI, 0-1.1%; P=.007).

Among the deployed SMs, 534 reported burn pit exposure. However, exposure to burn pits did not significantly alter the risk of either MGUS or LC-MGUS, with the combined prevalence of MGUS/LC-MGUS in this group being 6.7% (95% CI, 4.8%-9.2%), compared with a nonsignificant difference with the overall deployed cohort (P=.17).

“When considering the median age at deployment (37 years) and that samples were attained ~10 years later (~47 years of age), the observed prevalence is 6-fold higher than that reported in the population-based National Health and Nutrition Examination Survey Study (0.88% in the 40-49-year age group; Landgren, BCJ, 2017),” the researchers wrote.

Reference

1. Kazandjian D, Dew A, Hill E, et al. Increased risk of monoclonal gammopathy of undetermined significance in US military service members: a case-control study of 1,589 service members deployed to either Iraq, Germany, or not-deployed ex-US with or without reported burn pit and toxic smoke exposure. Presented at: 66th ASH Annual Meeting & Exposition. December 7-10, 2024; San Diego, CA. Abstract 4669.

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