Middle East Deployment and Lymphoid Malignancies in US Veterans: A Matched Case-Control Analysis

TL;DR

A study of US veterans found no increased risk of lymphoid cancers from Middle East deployments, but more research is needed.

Contribution

This study provides a large matched case-control analysis of deployment and lymphoid malignancies in veterans.

Findings

Deployment to the Middle East was not linked to higher lymphoid malignancy risk.

Exposure to OEF/OIF operations did not increase specific lymphoid cancer types.

Prospective studies are needed to better understand military exposure health effects.

Abstract

The United States was in several conflicts in the Middle East spanning decades with potential military exposures resulting in long-term health effects. Many veterans involved in these operations reported high levels of environmental exposures and concerns about health effects, including blood cancers such as lymphoid malignancies, related to exposures including depleted uranium and burn pits. The aim of our retrospective matched case-control study was to assess the association between deployment and the risk of developing lymphoid malignancies. Our study did not find an increased risk of developing lymphoid malignancies, highlighting the need for prospective studies on military exposures.

Background/Objective: US military personnel deployed to the Middle East were potentially subjected to harmful exposures, such as carcinogens from burn pits, which may increase the risk of lymphoid malignancies. Our objective was to determine the association between deployment and the risk of developing lymphoid malignancies. Methods: This was a retrospective nested matched case-control study from a cohort of 3.5 million veterans who enlisted in the military after September 2001 and were followed until death or last follow up through September 2024. Cases of lymphoid malignancies were identified by the VA Central Cancer Registry and controls were randomly selected from the same base cohort, matched by year of birth, year of enlistment, sex, race, and ethnicity. Exposure was defined as deployment to the Middle East as determined by identification on the VA Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) roster with confirmed dates of deployment or paystubs. Results: There were 1037 cases of lymphoid malignancies and 3572 matched controls. Deployment was not associated with a higher risk of developing lymphoid malignancies compared to non-deployment. Exposure to OEF/OIF was not associated with a higher risk of developing certain types of lymphoid malignancies. Conclusions: In this large, matched case-control study of US veterans, deployment to the Middle East was not associated with increased risk of developing lymphoid malignancies. While these findings do not support an increased lymphoid malignancy risk, important limitations remain, including the absence of detailed exposure and potential confounding variables. Prospective monitoring of specific types and doses of exposures during military deployment, development of lymphoid and other malignancies, and their underlying pathophysiology is indicated.