The first responders to the World Trade Center disaster who had severe exposure to the debris have an increased risk of early onset dementia, a study revealed.

The study published in the Jama Network revealed that there is a higher likelihood of developing dementia before reaching the age of 65 in the first responders to the 9/11 site who experienced severe exposure to toxic debris in contrast to minimally exposed responders or those who utilized personal protective equipment. This trend persisted even after accounting for demographic, medical, and social factors.

Researchers evaluated more than 5,000 WTC responders with an average age of 53, for more than eight years, from November 2014 to January 2023. The severity of toxic exposure was estimated based on the participant's responses to detailed questionnaires that included questions about the duration of the work and the use of PPE.

The study participants were evaluated for signs of dementia at the start of the study and during intervals in subsequent years, with key evaluations every 18 months. The results showed that 228 responders below the age of 60 (4.6% of the participants) who did not have dementia at the start of the study developed dementia over the next five years.

The researchers highlighted that among the general population under 60, the typical likelihood of developing dementia over a five-year follow-up would be around 0.5 percent.

"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. Also, the rates remained statistically significant over the less exposed group even after adjusting for social, medical, and demographic factors," lead author Sean Clouston said in a news release.

The results also showed that responders without dust exposure or those using protective gear had a low dementia rate of around 5-6 cases per 1,000 responders per year. However, responders not using protective gear and involved in risky tasks like digging through Ground Zero debris had a much higher rate of 42.36 cases per 1,000 people per year.

"Disasters often require an emergent response in dangerous conditions, but reliable use of PPE might help prevent the onset of dementia before age 65 years among individuals exposed to an uncontrolled building collapse," the researchers concluded.

"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. The full extent of neurodegenerative disease still needs to be determined," said Dr. Benjamin Luft, co-author of the study.