Background: There is a risk for accelerated cognitive decline in community members, including those who lived or worked in the surrounding community during the 9/11 World Trade Center (WTC) terrorist attacks and the aftermath. In particular, evaluating domain-specific cognitive function in relation to exposure to the dust cloud created by the destruction of the WTC towers on 9/11 considering the roles of depression and social support, may provide novel insight into cognitive vulnerability in this previously understudied community-based population. To address this issue, we conducted telephone-based interviews to assess the cognitive functions of recruited members of the WTC Environmental Health Center using standardized questionnaires.
Methods: Telephone cognitive assessments measuring MoCA (t-MoCA), delayed and immediate recall of the craft story (episodic memory), verbal fluency (animal, vegetable, F and L word naming), geriatric depression scale (GDS), nine-item Patient Health Questionnaire (PHQ-9), and social support survey (SSS) were conducted on 255 participants enrolled in the WTC community health study (U01OH012486). In linear regression models, t-MoCA, episodic memory, and verbal fluency scores were regressed first on WTC dust cloud exposure status with age, sex, and race/ethnicity (Non-Hispanic-White vs non-White and/or Hispanic) as covariates, then on GDS, PHQ-9, and the SSS adjusted with the same covariates.
Results: Exposure to the WTC dust cloud on 9/11 was associated with lower episodic memory (β=-0.24, 95%CI[-0.477,-0.004], p=0.047) and verbal fluency scores (β=-0.24, 95%CI[-0.467,-0.013], p=0.04), but did not reach significance in t-MoCA (β=-0.079, 95%CI[-0.321,0.163], p=0.521). While lower episodic memory was significantly associated with depression only on the PHQ-9 scale (β=-0.131, 95%CI[-0.252,-0.01], p=0.034), lower scores on verbal fluency and t-MoCA were significantly associated with depression only on the GDS (β=-0.117, 95%CI[-0.234,0], p=0.051 and β=-0.161, 95%CI[-0.283,-0.039], p=0.01). Higher scores on both verbal fluency and t-MoCA were significantly associated with better social support (β=0.122, 95%CI[0.007,0.238], p=0.038 and β=0.14, 95%CI[0.019,0.261], p=0.025).
Conclusion: Exposure to the WTC dust cloud on 9/11 was associated with poorer episodic memory and verbal fluency in a community-based sample. Cognitive performance was also differentially related to depression and social support, underscoring the importance of psychosocial factors when evaluating cognitive outcomes following disaster exposure.