Cross-sectional association between posttraumatic stress and cognition is moderated by pulmonary functioning in world trade center responders

Background

Posttraumatic stress disorder (PTSD) symptomatology and poorer pulmonary function are highly prevalent psychiatric and medical conditions. In the present study, we tested for the individual, additive, and modifying associations of PTSD symptomatology and pulmonary function with cognitive performance.

Methods

In this cross-sectional study, a total of 1,401 World Trade Center (WTC) responders (mean age = 53, SD = 8 years, 92% males) participated in the study. Cogstate assessment measured cognitive performance. PTSD symptomatology was measured using the trauma-specific version of the posttraumatic stress disorder checklist (PCL-17) adapted for the WTC attacks. The 1-second forced expiratory volume and forced vital capacity (FEV1/FVC) ratio was used to measure pulmonary function. Linear regressions with cognitive performance as the outcome were conducted to assess individual, additive, and moderating associations of PTSD symptomatology and pulmonary function.

Results

Higher PTSD symptomatology and poorer pulmonary function were negatively associated with cognitive performance. A 10% increase on the FEV1/FVC ratio moderated the association between PTSD symptomatology and cognition, whereby its association with cognition was stronger when PTSD symptomatology was higher (est. = 0.01, 95%CI = 0.004, 0.01, p < 0.001). When stratified by responder type, these associations persisted in trained (est. = 0.01, 95%CI = 0.01, 0.02, p < 0.001), but not in non-trained (est. = 0.004, 95% C.I. = −0.01, 0.02, p = 0.39) responders.

Conclusions

In the presence of higher PTSD, better pulmonary functioning is associated with better cognitive performance. Early intervention efforts to mitigate preventable cognitive decline in high-risk populations should be studied, especially since intervention in one modality may have an impact on others.