World Trade Center workers with asthma and post-traumatic stress disorder perceive airflow limitation more accurately.

BACKGROUND

Post-traumatic stress disorder (PTSD) is a major risk factor for increased asthma morbidity among World Trade Center (WTC) workers.

OBJECTIVE

To investigate whether differences in perception of airflow limitation mediate the association of PTSD with worse asthma control in WTC workers.

METHODS

We collected data from WTC workers on asthma control (Asthma Control Questionnaire and Asthma Quality of Life Questionnaire) and daily peak expiratory flow (PEF) measures over 6 weeks. Perception of airway limitation was assessed by comparing guessed vs actual PEF values. Post-traumatic stress disorder was diagnosed using the Structured Clinical Interview. We used unadjusted and adjusted models to compare PEF and perception measures in WTC workers with PTSD with those of workers without PTSD.

RESULTS

Overall, 25% of 224 participants had PTSD. Post-traumatic stress disorder was associated with worse Asthma Control Questionnaire (2.2±0.8 vs 1.1±0.9, P < .001) and Asthma Quality of Life Questionnaire (3.9±1.1 vs 5.4±1.1, P < .001) scores. Adjusted analyses showed no significant differences in PEF between WTC workers with (351.9±143.3 L/min) and those without PTSD (364.6±131.6 L/min, P = .55). World Trade Center workers with PTSD vs those without PTSD had increased proportion of accurate perception (67.0±37.2% vs 53.5±38.1%, P = .01) and decreased underperception (23.3.0±32.1% vs 38.9±37.5%, P = .004) of airflow limitation during periods of limitation. Similar results were obtained in adjusted analyses.

CONCLUSION

This study indicates that differences in perception of airflow limitation may mediate the relationship of PTSD and increased asthma symptoms, given WTC workers with PTSD have worse self-reported asthma control, an increased proportion of accurate perception, and decreased underperception, despite no differences in daily PEF measures.