New research appears to highlight another tragic aftereffect of the 9/11 terror attacks. Scientists have found evidence that responders exposed to dust and debris from the collapse of the World Trade Center are more likely to develop early onset dementia. The findings also suggest that protective personal equipment can help mitigate this risk should a similar disaster ever happen again.
The research was led by scientists from Stony Brook University. Stony Brook has maintained a long-running program treating and tracking the health of 9/11 responders. As part of this program, epidemiologist Sean Clouston and his colleagues have specifically focused on the long-term mental and cognitive outcomes of these survivors.
The team has previously studied how the chronic PTSD suffered by some responders may have contributed to other lingering health issues. But while they did find a connection between PTSD and mild cognitive impairment in this group, they also noticed that many survivors without PTSD were experiencing these problems as well, which led them to dig deeper. Knowing that some studies have begun to find a link between air pollution and dementia, they hypothesized that dust and debris exposure among these responders could be a key factor.
In this new study, the researchers studied the cognitive health of middle-aged responders between 2014 to 2022, specifically looking for diagnosed cases of early-onset dementia—an especially rare condition before the age of 65. Based on self-reported accounts of their experiences in the aftermath of the 9/11 attacks, the team grouped responders by the level of exposure they likely experienced as well as whether they were wearing masks or other protective equipment during their efforts.
While the team did hope to spot evidence for their hypothesis, even they were surprised by how readily apparent this connection was in their sample. Of the 5,010 volunteers under age 60 examined, 228 had been diagnosed with early dementia. The more dust that people were exposed to, the greater their odds of having dementia, even after adjusting for other possible factors, such as hypertension or a history of head injuries. Those in the most severe exposure group were over nine times more likely to develop dementia compared to the lowest exposure group after adjusting for these factors, and substantially more likely than the general public.
“We did find very quickly that the people who didn’t report any dust exposures, the people who always wore masks, seemed to be at a very low risk, and then for the rest, the risk of developing dementia increased incrementally by the more exposures that people reported,” Clouston told Gizmodo. The team’s results were published Wednesday in the journal JAMA Network Open.
These sorts of studies can only demonstrate a correlation between two things, not a direct cause-and-effect relationship. But the authors have collected other supporting data, such as previous research showing a link between exposure to 9/11 dust and measurable markers in the brain associated with dementia, such as neuroinflammation. Other research has found that exposure to this dust can worsen cognitive health in mice.
The study does lend more weight to the general idea that air pollution can be dangerous to our brains, though Clouston notes that 9/11 survivors were exposed to a wide range of pollutants, some of which would rarely be encountered anywhere else. At the same time, relatively common disasters, such as wildfires that reach buildings and homes, could conceivably expose people to similar kinds of pollution, so the implications of this research could be important for these events as well.
There are still many questions left to be answered about this link that Clouston’s team plans to continue studying. These include whether the dementia experienced by 9/11 survivors is biologically distinct from other types, exactly how the fine dust particles from the WTC attacks have harmed people’s brains, and how these exposures could continue to affect the cognitive health of survivors as they get older. But there is a silver lining to be taken from the team’s work—one that the team hopes will lead to lasting changes in how first responders and others are equipped to deal with similar crisis situations.
“I think we’ve, especially after covid-19, become much more aware of the importance of masking for lots of things. And in occupational spaces, some people were obviously already aware of the benefits of masking. So the forward-looking statement here is that more people wearing masks can help. And hopefully in future efforts, more people are given masks and asked to wear them, even if the air seems safe—let’s maybe be a little more skeptical of that and wear masks anyway,” said Clouston.
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