September 28, 2022
2 minute read
According to one study, in a large cohort of male Vietnam veterans, suspected exposure to Agent Orange led to an increased risk of developing idiopathic pulmonary fibrosis.
“This study is the first to identify an epidemiological association between Agent Orange, a toxin used during the war, and an increased risk of IPF in exposed veterans,” Bhavika Kaul, MD, MAS, study investigator and assistant professor at the University of California, San Francisco, told Healio.
According to Kaul, the pathway to chronic lung disease is complex, and the medical community is in the early stages of understanding how exposures increase the risk of pulmonary fibrosis.
“In particular, the role that military exposures play in the development of pulmonary fibrosis is unknown,” she said.
In the study published in the American Journal of Respiratory and Critical Care Medicine, Kaul and colleagues examined a nationwide cohort of US military veterans and characterized the risk of IPF associated with Agent Orange exposure. They included data on 3.6 million male Vietnam veterans who received care through the Veteran Health Administration between 2010 and 2019; among veterans, 26% had suspected exposure to Agent Orange. The median age at study entry for veterans with or without Agent Orange exposure was 62.7 versus 62.9.
The results indicated that IPF occurred more frequently in veterans exposed to Agent Orange than in those not exposed (2.2% versus 1.9%; OR = 1.14; 95% CI %, 1.12-1.16), a result that remained after adjusting for known IPF risk factors. (adjusted OR = 1.08; 95% CI, 1.06-1.1).
Overall, the attributable IPF risk for exposed veterans was 7% (95% CI, 5.3% to 8.7%).
IPF risk remained elevated in sensitivity analyzes that restricted the cohort to Vietnam veterans who served in the military as a surrogate measure for dose-response (unadjusted OR = 1.15; 95% CI, 1.13-1.18), when using a more specific definition of IPF (unadjusted OR = 1.17; 95% CI, 1.12-1.23) and using the previous criteria plus adjustment for IPF risk factors (aOR = 1.17; 95% CI, 1.09-1.25). When taking into account the concurrent risk of death, veterans exposed to Agent Orange remained more likely to develop IPF (HR subdivision = 1.13; 95% CI, 1.1-1.15).
“We found a greater risk of IPF in veterans exposed to Agent Orange,” Kaul concluded. “[Our study] establishes a premise for future work that examines the role of exposures in the development of fibrotic lung disease.