A study published in the American Journal of Respiratory and Critical Care Medicine found that 9/11 rescue and recovery workers who developed post-traumatic stress disorder after the attacks were more likely to develop new-onset asthma. The longitudinal study, which conducted a follow-up after about 5 years, was conducted by researchers at the Children’s Hospital of Pittsburgh. Findings showed that PTSD was linked to a more than two-fold increased risk of asthma.
At baseline, probable PTSD was linked to clinically significant bronchodilator response (BDR) among non-firefighter 9/11 workers in the study. Bronchodilators are medications that help patients with certain respiratory disorders, such as asthma and chronic obstructive pulmonary disease (COPD), breathe. Clinically significant BDR is indicative of respiratory issues. The findings suggest that PTSD may be an independent risk factor for asthma. The researchers wrote, “This finding strongly supports an expanding body of literature linking stress-related disorders such as PTSD to the pathogenesis of asthma, and suggests that physicians treating adults with PTSD should be aware of their potentially increased risk of asthma,”
The study followed 3,757 9/11 workers who have never smoked and did not have asthma at the beginning of the study. After five years, researchers found that those with PTSD had a 2.41-fold increased risk of new-onset asthma after adjustment for other factors such as age and gender. The analysis also found that BDR at baseline was linked to a 3.13-fold increased risk of asthma.
“We looked at lifetime non-smokers to avoid the risk that asthma may be confused with COPD,” said study author Juan Celedón, MD to Medpage Today.
Previous studies have suggested a link between PTSD and asthma in 9/11 rescue workers. This study, however, is the first to look at PTSD participants who did not have asthma when they enrolled in the study. Excluding those with asthma at baseline strengthens the findings, because the researchers reduced the chances that the asthma was caused by other factors. It also means that the asthma was unlikely to have caused PTSD.
The study authors wrote, “Unlike results from previous cross-sectional studies, ‘reverse causation’ (e.g., asthma leading to PTSD symptoms) is an improbable explanation for our findings for incident asthma, since this analysis was first conducted after excluding subjects who had a pre-existing asthma diagnosis at baseline, and then repeated after further exclusion of subjects with clinically significant BDR at baseline, obtaining very similar results,”
The study was limited by confounding factors of PTSD and asthma, such as other mental illness, family history of asthma, or exposure to environmental hazards other than 9/11 and smoking. Additionally, researchers did not have BDR data for the baseline visit in addition to information about a clinical diagnosis of PTSD.