A study of Global War on Terror veterans found that those who deployed were at less risk of dying from cancer than their fellow troops who didn’t deploy, possibly because those sent overseas were healthier in the first place, according to a paper published Wednesday in the American Journal for Cancer Research.
Study authors looked at 661 veterans’ cancer deaths between 2001 and 2018, comparing whether they had deployed and experienced combat, deployed and not experienced combat or not deployed.
“Non-deployers were 34% more likely to die from cancer compared with deployers who did not experience combat, accounting for smoking and other health behaviors, age, sex, race, ethnicity, and military characteristics,” according to a Tuesday release from the Naval Health Research Center, headquarters of the Millennium Cohort Study, a Defense Department research effort to study the long-term effects of military service that began in 2001.
The reports findings seem at odds to the rash of illnesses reported by GWOT veterans exposed to burn pits, which has led to recent legislation that treats a host of possible issues as service-connected.
The study authors say their findings does not negate the damage suffered by toxic exposure during deployments.
“Risks from specific exposures encountered during deployment, such as burn pits … may be associated with cancer mortality,” Sheila Castaneda, a deputy principal investigator with the Millennium Cohort Study, told Military Times. “In order to examine the impact of deployment-related exposures, comparisons of health outcomes would need to be examined among deployers who were exposed and those not exposed.”
What they are likely seeing is the “healthy deployer effect,’” Dr. Victoria Cassano, a retired Navy doctor who has testified on toxic exposures, told Military Times, referring to the requirement that troops have to be rated in fairly top condition to deploy.
A 2016 study of 200 troops deployed to Balad, Iraq, and Bagram, Afghanistan, had similar results, which were also attributed to the “healthy deployer effect.”
The latest study didn’t find any connection to branch of service or military occupation with cancer death risk, but found that enlisted troops were three times as likely to die of lung cancer as officers, even after controlling for smoking.
“This finding may be due to tasks more frequently performed by enlisted personnel that expose them to occupational airborne hazards such as exhausts, emissions, and other respiratory toxicants,” the release said.
Troops with higher education levels ― including enlisted versus officers, who are required to have a bachelor’s degree ― were associated with less cancer death risk, while smoking and “life stressors” were associated with higher risk.
But there is another side of veterans cancer research that has shown “protective factors” to deploying.
The recent Millennium Cohort paper found that not only were deployed troops less likely to die of cancer, but of veterans who died of cancer before age 45, those who didn’t deploy were 80% more likely to die than those who didn’t experience combat downrange.
“The risk of cancer death did not differ between deployers who experienced combat compared with those without combat experience,” according to the release. “These findings are consistent with the healthy deployer effect where personnel who deploy are considered healthier and more physically fit than those who do not.”
Thanks to the PACT Act, which went into effect Jan. 1, more than 20 illnesses, including 12 types of cancer, are now presumed service-connected, without the need to prove a specific exposure downrange or in garrison.
The Millennium Cohort Study is set to continue through at least 2068, Castaneda said, which will give researchers ample to see if they can draw new conclusions as time passes. It’s possible, for example, that more deadly cancers will emerge in combat deployed veterans beyond the window of 2001 to 2018 in the study.
“This study is a first glance at cancer mortality within the Millennium Cohort Study as it is still a relatively young cohort,” she said. “Our goal is to expand on this research as a majority of the cohort reaches middle-aged and older adulthood.”
Meghann Myers is the Pentagon bureau chief at Military Times. She covers operations, policy, personnel, leadership and other issues affecting service members.