When the World Trade Center towers collapsed on September 11, 2001, tens of thousands of people rushed to help: firefighters, paramedics, police officers, volunteers and construction workers were among them. While they tried to save lives, recover the dead and finally clear away the gigantic amounts of rubble, they risked their own health – and not just in the short term. The most recent example is the results of a study just conducted in Journal Jama Network Open published study. It suggests that the helpers at that time had an increased risk of early dementia.
The scientists, led by epidemiologist Sean Clouston from New York’s Stony Brook University, examined more than 5,000 people who undertook rescue or cleanup work in the chaos of Ground Zero. 228 of them developed symptoms consistent with dementia before the age of 65. The researchers did not examine the specific types of dementia.
Such early dementias are relatively rare; in the general population, about one in 1,000 people suffer from the condition each year. However, among the helpers from September 11th, almost 15 out of 1,000 developed the early cognitive disorder each year.
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It was found that the longer and more intensively people were exposed to the dust and toxins in the rubble field, the greater the risk of dementia. Helpers who wore protective clothing and breathing masks or who only worked at Ground Zero for a short time were more than twice as likely to develop early dementia as the general population. Those who worked unprotected for weeks through rubble, debris and ash were almost 40 times more likely to receive an early dementia diagnosis.
Large differences between the less and more heavily stressed helpers remained even when the researchers took other potential influencing factors into account: such as other illnesses, head injuries, psychological stress as a result of the disaster, high alcohol consumption and – as far as is known – a genetic susceptibility to early Alzheimer’s disease.
It is still possible that the high risk of dementia is due to other factors not taken into account in the study. The authors are therefore unable to prove a causal link between the conditions on the rubble site and the subsequent dementia. In a press release, co-author Benjamin Luft called the results “an important step” towards proving that dust and toxins resulting from the terrorist attacks continue to have devastating consequences for those affected.
A connection between fine dust and neurological diseases has been discussed for some time
The authors base their assessment on earlier observations. Previous work had already shown that former 9/11 responders later had increased cognitive problems. Brain scans of emergency responders at the time revealed signs of inflammation and changes that are typical of Alzheimer’s.
There is also evidence in the research literature that high levels of fine dust pollution generally promote dementia. The particularly fine particles with a diameter of less than 2.5 micrometers can reach the brain, trigger inflammatory reactions and thus damage the organ.
After the collapse of the World Trade Center, elevated concentrations of these fine particles were measured around its remains for more than six weeks. However, the dust that was kicked up by the collapse of the Twin Towers was different from the usual Fine dust that comes from traffic, coal-fired power plants and industrial plants. The haze that hung over the accident site at the time contained, among other things, powdered glass, lead, polycyclic aromatic hydrocarbons and dioxins, write the authors of the current study. To what extent they directly or indirectly increase brain damage cannot yet be said with certainty.