A new study at Denver’s National Jewish Health found an unexpected potential culprit for lung disease in some combat veterans: silica, which is one of the most common elements in dust, soil and sand.
The study, published in the International Journal of Environmental Research and Public Health, examined lung tissue from 65 people with unexplained shortness of breath and other respiratory symptoms after deploying to Afghanistan or Iraq. Deployed veterans were more likely to have silica in their lungs than people who weren’t in the armed forces, with combat veterans showing more damage than service members who worked in other jobs.
People with combat roles tended to have a variety of unhealthy respiratory exposures, including burn pits, sandstorms, diesel exhaust, tiny particles generated by explosions, dust from heavy equipment on dry soil, and pollution from local industries or trash burning, said Dr. Cecile Rose, an occupational and environmental pulmonologist at National Jewish Health.
She and the other researchers didn’t think silica would be the primary contaminant they’d find in veterans’ lungs.
“That was unexpected, but not surprising” when considering their exposure to dust and sandstorms, she said.
People who inhale large amounts of silica over a prolonged period can develop silicosis, a disease in which inflammation in the lungs causes scarring and difficulty breathing, Rose said. Silica inhalation is one factor in the increase in cases of black lung disease among coal miners in recent decades, because the miners have to cut through other rock types to reach narrow coal seams, she said.
“Silica dust is a powerful stimulant of lung inflammation,” she said.
Lung samples taken from people who died in accidents and hadn’t deployed overseas during their lifetimes showed small amounts of silica, but not comparable to what the combat veterans had, Rose said. Because the veterans were younger and less likely to have smoked, if anything, their lungs should have looked healthier, she said.
People who inhale significant amounts of silica can reduce their likelihood of disease by limiting further exposures, but that may not be feasible for career soldiers, Rose said. They also would want to avoid civilian jobs that would increase their risks, like mining, stone cutting and certain construction trades, she said.
Not everyone who served in combat experienced the same hazards, and the country needs more research to determine who needs careful lung monitoring, Rose said. Combat veterans shouldn’t ignore lung symptoms, though, and might consider joining the Airborne Hazards and Open Burn Pit Registry to help with research, she said.
“We don’t really know how many people are at risk,” she said.
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