Lung Effects of Particulate Matter Exposure in WTC First Responders Still Redound Decades Later

Beyond the lives taken immediately in the terrorist attacks on the World Trade Center (WTC) on September 11, 2001, the attacks also created an insidious threat among those exposed to the toxic dust: long-term lung injury and illness. According to abstracts presented at the CHEST Annual Meeting 2023, that exposure can give rise to a complex interplay of airway and digestive diseases, and there remains a need to find and test interventions that can help mitigate the effects.

Auscultation, man | Image credit: © RFBSIP - stock.adobe.com

The abstracts were part of a session on occupational and environmental lung health held on October 8 during the CHEST meeting in Honolulu, Hawai‘i. In addition to 3 abstracts on lung symptoms among veterans exposed to particulate matter while deployed, 2 researchers with the New York University Grossman School of Medicine presented their work among firefighters who had responded to the attacks on the WTC.

First, predoctoral fellow Rachel Lam delivered findings from the randomized Food Intake REstriction for Health OUtcome Support and Education (FIREHOUSE) trial (NCT03581006) on diet and the microbiome in WTC-exposed firefighters with lung disease.¹ Metabolic syndrome is known to predict WTC-related lung injury in a cohort of responders from the Fire Department of New York, and other research indicates the role of the microbiome in mediating inflammatory responses in the lungs, so Lam and colleagues aimed to test the effects of a low-calorie Mediterranean diet in a cohort of these firefighters.

After 6 months, 2 measures of microbial diversity did not differ between the diet group (pilot: n = 5; validation: n = 15) and a control group (pilot: n = 5; validation: n = 16), but the researchers did note an increase in Bacteroides ovatus in those who adhered to the diet. Although B ovatus has been shown in mouse models to have protective health effects, Lam noted that future studies will be needed to confirm the microbiome’s association with clinical outcomes in the firefighter cohort.

Referencing the FIREHOUSE trial’s aim of conducting a multi-omic assessment of WTC-associated lung diseases by leveraging a longitudinal cohort of firefighters, Lam said that her team will “continue looking at the microbiome, epigenome, and metabolome…to then lay the groundwork for expanding the findings from the trial as well as how it can help other affected cohorts.”

Next, Sanjiti Podury, MD, presented results on the contribution of respiratory medication use to the risk of certain aerodigestive diseases in a cohort of WTC responders with airway hyperreactivity.² Prior research has linked WTC exposure to gastroesophageal reflux disease (GERD) and Barrett esophagus, but this work looked specifically at the impact of short-acting β₂-agonists (SABAs) and steroids on the risk of these conditions in a group of 1309 firefighters.

They found that SABA use was associated with increased odds ratios of developing GERD (4.10; 95% CI, 3.52-4.78) and Barrett esophagus (1.99; 95% CI, 1.63-2.44), as was steroid use (GERD: 4.69; 95% CI, 3.77-5.83; Barrett: 2.30; 95% CI, 1.83-2.89), after adjusting for age and smoking (P < .001). Interestingly, the level of exposure to the WTC dust seemed to be an exacerbating factor; relative to those who arrived on site within the 2 weeks after the attacks, those who arrived on site the morning of September 11 had a 34.8% higher risk of developing GERD and those who arrived on the afternoon of September 11 had a 28.8% higher risk. Similar patterns were observed for Barrett esophagus, at 41.0% higher risk for those who arrived in the morning and 31.7% higher risk for those who arrived that afternoon.

“We would like to study further into this overlap between GERD, Barrett, and airway hyperreactivity to try to distinguish the phenotypes of these diseases,” Podury said. “Future studies could also include an assessment of the inhaler route used and its role in aerodigestive diseases, and an analysis of noninvasive biomarkers.”

In response to a question about the generalizability of the findings asked by an audience member who described himself as a pulmonologist by day and firefighter by night, Anna Nolan, MD, senior investigator on both abstracts, said that the results may apply to other firefighters because the mechanisms involved are the same. Although the exact composition of the smoke differs across wildfires, house fires, and the WTC fires, particulate matter is known to exact a toll on the body’s airways and inflammatory pathways.

References

1. Lam R, Kim J, Ramprasad M, et al. Diet and the microbiome in WTC particulate matter­–exposed firefighters with lung disease: the FIREHOUSE randomized clinical trial. Abstract presented at: CHEST Annual Meeting 2023; October 8-11; Honolulu, HI. doi:10.1016/j.chest.2023.07.3309

2. Javed U, Podury S, Kwon S, et al. Short-acting beta-agonists and steroids are associated with the development of aerodigestive disease in particulate matter­–exposed firefighters. Abstract presented at: CHEST Annual Meeting 2023; October 8-11; Honolulu, HI. doi:10.1016/j.chest.2023.07.3311