Agent Orange exposure is associated with increased risk for developing monoclonal gammopathy of undetermined significance (MGUS), a plasma cell disorder found in all patients who develop multiple myeloma, a recent study has confirmed.1

Agent Orange has long been implicated in increased cancer rates among exposed veterans. Cancer risk is thought to be due to the presence of a contaminant chemical, TCDD.1,2

Researchers led by Ola Landgren, MD, of Memorial Sloan Kettering Cancer Center in New York City, conducted a prospective cohort study in 2013 to 2014 by screening veterans exposed to Agent Orange (n=479) and matched controls (n=479) who were in Southeast Asia at the same time with similar duties, but did not include Agent Orange missions.

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All patients were screened for MGUS. Serum levels of Agent Orange and TCDD were measured in blood samples collected in 1987, 1992, 1997, and 2002 during a U.S. Air Force health study.

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Although having similar demographic and other characteristics as the control veterans, those who were exposed to Agent Orange had a significantly higher prevalence of MGUS (odds ratio = 2.37, 95% CI: 1.27-4.44; P=.007).1 In adjusted data, “that means that among Agent Orange–exposed veterans there is a more than double amount of MGUS,” said Dr. Landgren.

Of note, the risk of MGUS was increased significantly only among veterans younger than age 70. Finally, increased levels of TCDD were observed in veterans who developed MGUS after Agent Orange exposure, suggesting a connection.

These findings “provide the first direct scientific evidence for an association between the multiple myeloma precursor, MGUS, and Agent Orange/TCDD exposure,” wrote Dr. Landgren.1