The earliest responders to reach the site of the destroyed twin towers of the World Trade Center on Sept. 11, 2001, are at highest risk for chronic obstructive pulmonary disease and asthma/COPD overlap (ACO) among all those who worked at the site. The 9/11 attack was the deadliest terrorist attack on American soil.
The findings come from a case-control study that included nearly 18,000 emergency responders and volunteers. The investigators found that those who arrived at the site within 48 hours had an approximately 30% higher risk of developing COPD than those who arrived later, after adjustment for smoking and obesity, reported Rafael E de la Hoz, MD, a professor of environmental medicine, public health, and medicine at Mount Sinai Medical Center, New York, and colleagues.
“In this largest World Trade Center occupational cohort, spirometrically defined COPD and ACO were both modestly but significantly associated with World Trade Center exposure intensity, but the association seemed driven by the overlap,” he said in a narrated poster presentation during the European Respiratory Society 2021 International Congress.
“Around the world, we rely on our emergency workers to help when disasters occur,” commented Arzu Yorgancıoğlu, MD, professor and head of the department of pulmonology at Celal Bayar University, Manisa, Turkey, who was not involved in the study.
“This study shows how important it is to keep monitoring the health of workers, like those who attended the World Trade Center site 20 years ago, as occupational exposure to pollutants can lead to COPD. What we can learn from research like this is not only how best to care for emergency workers who operate in dangerous conditions but also how we can protect them in their work in the future,” she said.
Inconsistent findings
Fire and police personnel, emergency medical workers, construction workers, and others who labored amid the lingering pall of toxic dust and smoke at the World Trade Center site have developed asthma and other lower respiratory tract diseases over the ensuing decades.
“As the occupational cohorts age, there are concerns about chronic, longer latency, and disabling respiratory disease,” Dr. de la Hoz and colleagues wrote.
There have been inconsistent reports about the potential associations between COPD and ACO and the intensity of occupational exposure at the World Trade Center site. This prompted the investigators to further explore these associations using spirometry-defined disease.
They assessed data on 17,996 former World Trade Center site workers who had undergone at least two good-quality spirometric evaluations from 2002 to 2018.
To be classified as having COPD, workers had to have fixed airway obstruction. Those in the ACO subgroup were also required to have prebronchodilator obstruction with forced expiratory volume in 1 second of more than 400 mL in response to bronchodilation.
The patients were matched for sex and height within 5 cm using a 1:4 nested case-control design. Missing data were imputed.
Earliest arrivals paid the highest penalty
Of the total cohort, 85.4% were men, and 85.6% were overweight or obese. A total of 586 workers (3.3%) met the case definition for having COPD; 258 (1.4%) met the definition for having ACO.
The investigators found that the prevalence of self-reported ACO was six times higher than the prevalence of spirometry-confirmed disease. Among those who reported an onset date, 56.7% reported having asthma before COPD; the remainder reported having COPD first.
In analyses adjusted for age, sex, cohort entry period, smoking status, body mass index, metabolic syndrome parameters, and eosinophil levels, both COPD and ACO were significantly associated with early arrival at the World Trade Center site, with an adjusted odds ratio for COPD of 1.3 (95% confidence interval, 1.03-1.64), and an OR for ACO of 1.66 (95% CI, 1.1-2.49).
There was no significant interaction between early site arrival and smoking status.
The association between early exposure and COPD was no longer significant when those with ACO were excluded, the authors noted.
“We also observed that COPD more often followed asthma in these workers than the reverse, suggesting that asthma may have been on the path to COPD in most workers affected by the inhaled toxicants at the disaster site,” Dr. de la Hoz and colleagues wrote.
In addition, “our data suggest that self-reported physician diagnoses of COPD, asthma, and ACO are poorly correlated with objective data in this cohort,” they concluded.
The study was supported by the Centers for Disease Control and Prevention and the National Institute for Occupational Safety and Health. The authors and Dr. Yorgancıoğlu disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.