World Trade Center responders can still take steps to lower lung injury risk

Reducing excess body fat and adjusting factors of metabolic syndrome can greatly lower the risk for lung disease among World Trade Center first responders, according to data in the American Journal of Respiratory and Critical Care Medicine.

The study also found that a high BMI and high exposure to toxins from the attack were among the greatest risk factors for “World Trade Center-lung injury” (WTC-LI).

“Our observations have been eye-opening. It was important for me as a health care provider to see this complex relationship evolve over time and to see that it was still possible to help these first responders mitigate their risk even after so many years,” Anna Nolan, MD, MS, study co-author and a professor of medicine and environmental medicine at NYU School of Medicine, told Healio Primary Care.

In a press release, Sophia Kwon, DO, MPH, another study co-author and a fellow in the division of pulmonary, critical care and sleep at NYU Langone Health, said the findings “should reassure World Trade Center first responders that there are steps they can take to protect their lungs even decades after exposure.”

Kwon, Nolan and colleagues conducted a dynamic risk assessment to examine the association between metabolic syndrome and WTC-LI. They analyzed 20 years of data on 5,738 firefighters active on 9/11. Among them, 99.77% were men, the average age on 9/11 was 40.09 years, 93.74% were white and 32.31% were ever-smokers.

According to the press release, the study is “likely the longest-running and most thorough exploration of the impact of metabolic syndrome on lung injury in 9/11 firefighters.”

Among the first responders included in the study, 1,475 later developed lung disease. The researchers found that a BMI of 30 kg/m² or greater and dyslipidemia significantly predicted WTC-LI. Also, metabolic syndrome risk factors “exponentially” increased the risk for lung injury, the researchers wrote.

Individuals with WTC-LI had higher BMI, systolic BP, diastolic BP and triglycerides. Those with lung injury were more likely to be ever-smokers (35.25% vs. 31.29%; P = .006) and have high exposure to toxins compared with controls (19.73% vs. 15.72%; P < .001).

However, two-stage models showed that reductions in BMI, glucose, systolic BP and diastolic BP were associated with a decreased risk for WTC-LI. For example, a 1 kg/m² reduction in BMI among a first responder at average height was “equivalent to approximately a 7 lb weight loss, and reduced risk for WTC-LI by 20.38%,” the researchers wrote. Similarly, an increase in HDL of 10 mg/dL reduced the risk for WTC-LI by 89%, a reduction in fasting blood glucose of 10 mmol/L reduced the risk by 72.36%, and a 10 mmHg reduction in systolic BP and diastolic BP reduced the risk by 74.93% and 136.44%, respectively. Age, gender, race or duration at site did not seem to affect lung injury risk, according to the researchers.

“Dynamic assessment allowed us to define the risk of the development of WTC-associated lung disease based on multicollinear metabolic syndrome characteristics, smoking and WTC-exposure,” the researchers wrote. “BMI and dyslipidemia imparted more risk of WTC-lung disease development than smoking. Furthermore, mitigating metabolic syndrome can decrease the risk of WTC-lung disease.”

The implications of the findings extend beyond 9/11 first responders, Nolan noted.

“The lessons from our investigation can be applied not only to firefighters but to the millions of city dwellers exposed to air pollution on a daily basis,” Nolan said in the release. “They should be aware that while their environment poses real health risks, they may still minimize their risk of lung disease even if they cannot change their exposure.”

References:

EurekAlert! Decades after toxic exposure, 9/11 first responders may still lower their risk of lung injury. https://www.eurekalert.org/news-releases/926936/. Accessed September 2, 2021.

Kwon S, et al. Am J Respir. 2021;doi:10.1164/rccm.202006-2617OC.