More 9/11 toxin exposure boosts first responders’ dementia risk

A recovery worker searches the debris field of the collapsed south tower as cleanup and recovery efforts continue at the disaster site of the World Trade Center March 7, 2002 in New York City. (Credit: Spencer Platt/Getty Images )

First responders who had more exposures to World Trade Center-related toxins during 9/11 and its aftermath have dementia at a higher rate than other responders with fewer WTC-related toxic exposures, a new study indicates.

Evidence that these 9/11 first responders have since suffered poorer brain health than others not exposed to WTC toxins has mounted in recent years.

For the new study, published in JAMA Network Open, researchers evaluated more than 5,000 patients from the Stony Brook WTC Health and Wellness Program for signs of dementia.

The study lasted more than eight years, from November 2014 to January 2023. The average age of the participants at the start of the study was 53 years old.

The investigation of this large sample of 9/11 first responders centered on assessing if there is an association between occupational exposures while responding to the WTC disaster and the incidence of dementia before 65 years of age, says lead author Sean Clouston, professor in the program in public health, and in the family, population, and preventive medicine department in the Renaissance School of Medicine at Stony Brook University.

Overall, the research team found that 228 9/11 responders without dementia and under 60 years old at the start of the study developed dementia over the next five years. This is 4.6% of the responders included in the study. Clouston and colleagues point out that in the general population of people under 60, the incidence of them developing dementia over five years of follow-up would only be about 0.5%.

Clouston explains that in responders who reported no dust exposures or those who wore personalized protective equipment, or PPEs, (masks, hazmat suits for example), approximately five to six out of every 1,000 responders evaluated developed dementia each year.

However, for responders who did not use PPEs, and who reported dangerous occupational activities such as digging through Ground Zero debris, the dementia incidence rates reached 42.36 per 1,000 people each year.

“This rate of dementia in those reporting many exposures and limited protection is not only statistically significant, it is alarming for a patient cohort that clearly shows a strong association between exposure and the incidence of dementia under the age of 65,” says Clouston. “Also, the rates remained statistically significant over the less exposed group even after adjusting for social, medical, and demographic factors.”

Coauthor Benjamin Luft, director of the Stony Brook WTC Health and Wellness Program, who has monitored the health and evaluating these responders for 20 years, believes that clinical research on the cognitive health of responders must continue.

“These findings are a major step forward in establishing that the dust and toxins which were released as a result of the calamitous terrorist attacks on 9/11 continue to have devastating consequences on the responders,” Luft says. “The full extent of neurodegenerative disease still needs to be determined.”

All of the study participants were evaluated for signs of dementia by professionals at the Stony Brook WTC Health and Wellness Program at the start of the study and during intervals in subsequent years, with key evaluations every 18 months.

Dementia was diagnosed algorithmically by the presence of new-onset cognitive impairment in individuals across two domains of cognitive functioning—episodic memory and executive function. Cognitive performance in individuals was measured regularly by trained research staff using the Montreal Cognitive Assessment with alternative versions used longitudinally to reduce test bias. Global cognitive performance was measured using a standard scoring by mental health practitioners.

The researchers determined toxic exposure severity based on individuals’ responses to a detailed questionnaire of WTC exposures and exposure-related occupational activities that included exposure to fine particulate dust and potentially neurotoxic debris—both at Ground Zero and related 9/11 cleanup sites in Manhattan and Staten Island. Questions about duration and work and use of PPE were included within the questionnaire. The team categorized exposure level into five categories from low to severe.

They also state that a central strength of the study is the development of its exposure severity scale that considered the type of work that responders completed, the duration and severity of exposure, and use of PPE.

The Centers for Disease Control and Prevention and the National Institutes of Health’s National Institute on Aging supported the work.

Source: Stony Brook University