Clinicians evaluating patients’ occupational histories should take into account military service, given that a study of US military veteran rosters has found an increase in the risk of chronic obstructive pulmonary disease (COPD). Investigators found that 44% of veterans had been exposed to inorganic dust. The study by Paul Blanc, MD, and colleagues was published online in the journal Chest.
“Occupational factors should always be considered a possible contributor to COPD. Many clinicians still wrongly believe COPD is only a smoking-caused condition,” said Blanc, professor of medicine at the University of California, San Francisco, in an interview with Medscape Medical News.
The adjusted analysis showed that among ever-smokers, a moderate or high likelihood of exposure to inorganic dust during military service was associated with a 23% increase in the odds of having COPD (odds ratio [OR], 1.23; 95% CI, 1.15 – 1.31). The odds of having COPD were not elevated in never-smokers (OR, 0.94; 95% CI, 0.87 – 1.01). The increase in odds of COPD associated with dust exposure was 25% (OR, 1.25; 95% CI, 1.22 – 1.28) in the overall population. Those with asthma were excluded from the main analysis. When those with asthma and concomitant COPD were included, the estimated ORs remained similar.
The authors analyzed data from US military service rosters from operations beginning in 2001 in Iraq, Afghanistan, and surrounding countries in the region and developed a job exposure matrix (JEM) for analysis of Veteran’s Administration outpatient- and inpatient-associated COPD diagnostic codes (ICD -9: 491, 492, 496; ICD-10: J41, J43, J44) through the end of September 2018. Inclusion required at least two encounters with these codes at least 30 days apart and at least one prescription for a commonly prescribed medication for COPD (bronchodilators and corticosteroids). The JEM data, which categorize military duties as likely (high probability), somewhat likely (moderate probability), or not likely (low probability) to involve inorganic dust exposure, are based on the final but not necessarily longest-held military occupation codes. Overall, 0.4% (n = 1728) of the eligible population of 427,591 (88.2% men) had received a COPD diagnosis. The mean age at first Veterans Administration encounter was 29.9 years; the mean age at last encounter was 37.0 years, with a median of 4.3 years of military service.
Rates of dust exposure in military occupations were 56.2% for low/no exposure, 43.8% for any exposure, 22.2% for moderate exposure, and 21.6% for high exposure.
“These findings,” Blanc and colleagues conclude, “are consistent with an expansive biomedical literature supporting a substantive role of occupational exposures in the etiology of COPD.” A further consideration, the authors note, is that the findings add to growing appreciation that the potential adverse health effects of occupational aspects of military service should be taken into account.
“Physicians should inquire about exposure to vapors, gas, dust, or fumes in both military and nonmilitary jobs,” Blanc added in the interview. “Physicians should consider military service as a source of occupational exposures,” he said. He noted that the recommendation is not geospecific but rather is generic to military occupations regardless of locale.
Need for Further Research
“It’s useful for clinicians to know about this modestly elevated risk for COPD,” commented Mary Jo Farmer, MD, assistant professor of medicine at UMASS Chan Medical School–Baystate, Springfield, Massachusetts, “and to therefore inquire about military deployment. It would be very helpful, though, in future research to explore the impact on COPD of exposure to specific irritants and to test also for any correlations with smoking history.”
As a study limitation, the investigators state that the JEM data do not otherwise (beyond ever-smokers) offer details regarding specific vapors, gas, fume exposure (eg, dust storms, burn pit combustion by-products), or length of service.
The study was supported by a Veterans Affair Merit Award and by the Russell/Engleman Rheumatology Research Center for Arthritis. The authors and Farmer have disclosed no relevant financial relationships.
Chest. Published online April 22, 2022. Abstract
For more news, follow Medscape on Facebook, TwitterInstagram, and YouTube.