13 June 2024

Exposure to dust increased the risk of dementia

We know from past research that the rescue workers who cleaned up the aftermath of the terrorist attack on the World Trade Centre on 11 September 2001 seriously compromised their health while on duty. In a new paper, US medical researchers have revealed that the exposure to dust and debris particles to which the liquidators were exposed while removing the rubble increased their risk of early dementia.

The twin towers of the World Trade Centre (WTC) in New York collapsed after being rammed by terrorist hijacked passenger airliners. 2,751 people died then, including 157 passengers and crew members aboard both planes.

As a result of the collapse, dust and particles of debris containing hazardous chemicals, crushed glass and heavy metals were scattered across Lower Manhattan. Responders involved in debris removal were exposed to high levels of airborne contaminants and reported acute gastrointestinal discomfort and difficulty breathing.

Since long-term inhalation of air polluted with dust and particulate matter is considered a potential risk factor for early dementia, researchers from the State University of New York at Stony Brook (USA) suggested that participation in debris removal after the WTC attack increased the likelihood of associated cognitive impairment in the responders. Observations of more than 5,000 rescue workers confirmed the suspicions. An article with the findings was recently published in the journal JAMA Network Open.

For the analysis, the researchers took data from a medical monitoring programme for WTC attack survivors living on Long Island in New York City. The sample included 5,010 people under the age of 60, mostly men, who did not have dementia at the time of the first cognitive assessment. The screening was then repeated every 18 months for an average of five years. The participants' age at the time of inclusion in the programme averaged 53 years.

The subjects were divided into several groups according to the degree of exposure to which they had been exposed: mild, moderate, moderate, high and severe. Most of the liquidators were classified into the first and second categories. The former included those who used personal protective equipment or did not work in contaminated air with fine dust and potential neurotoxins.

During the participants' follow-up, they were diagnosed with dementia 228 times before the age of 65, which is considered early onset. Analyses showed that the likelihood of facing the disease was greater the more severe the exposure to toxic dust that the responders were exposed to.

After adjusting for social, demographic, health and other factors, it was found that each one unit increase in exposure severity correlated with a 42 per cent increase in the risk of early onset dementia. Participants with the most severe exposure had a 42 times higher risk of early dementia than the population average.

This is not the first time researchers have studied the diseases that afflicted rescue workers who removed debris after the 11 September attacks. In 2022, experts from the same American university found that people who removed the consequences of the attack on the WTC were three times more likely than the general population to show signs of cognitive impairment.

Nevertheless, the new work is important because it is the first to show a link between early dementia and the degree of dust exposure. In addition, the findings suggested that the use of personal protective equipment reduced the risk of adverse effects, study co-author Sean Clouston told CBS News.

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