LOS ANGELES — Long-term exposure to one of the most prevalent types of air pollution may increase the risk of developing dementia, a debilitating neurological disease associated with memory loss and reduced cognitive function, according to a new study.
Researchers at the University of Michigan have concluded that people living with higher levels of fine particulate matter, or PM2.5, could face a greater risk of being stricken with dementia, according to a study published recently in the Journal of the American Medical Association.
Scientists monitored the cognitive health of nearly 28,000 people aged 50 or older living across the United States between 1998 and 2016. Fifteen percent of this group developed dementia, and those who lived in areas with more PM2.5 were more likely to succumb to the neurodegenerative illness.
Brian van der Brug, Los Angeles Times
Los Angeles resident Carmen Green jumps rope in September 2020 at the shuttered closed Griffith Observatory in spite of dense smoke from wildfires in Southern California.
Based on those results, the study estimates fine particulate pollution may be responsible for 188,000 dementia diagnoses each year in the United States. And evidence suggests the health risk may vary with the type of PM2.5 — a catchall term for suspended material about 30 times smaller than the width of a human hair.
Scientists examined exposure to nine different types of particulate ranging from traffic to coal combustion. Exposure to pollution from wildfires and agricultural dust had the strongest ties to the prevalence of dementia, according to Boya Zhang, lead author and research fellow at the University of Michigan.
“The main reason for this distinction may be due to the different physical or chemical characteristics of the PM2.5 from these different sources. All particles are harmful to you, but wildfires and agriculture (dust) may be more harmful to your cognitive health.”
As people live longer and the global population continues to trend older, the findings underscore the importance of limiting exposure to air pollution to cognitive health. But the study also arrives amid a particularly devastating Canadian wildfire season when smoke and soot drifted across North America and engulfed such cities as Chicago and Detroit, highlighting how these intensifying natural disasters can imperil millions of people thousands of miles away.
The research is also concerning for Californians, who have seen their state ravaged by record-setting wildfires and drought that turned thousands of acres of farmland into dust bowls.
The study also serves as a reminder of the sweeping effects air pollution can have on human health. Particulate pollution has already been found to contribute to lung disease, heart attacks, strokes, low birth weight and diabetes.
And, earlier this month, a new study suggested a connection between PM2.5 exposure and the prevalence of antibiotic-resistant bacteria, also known as superbugs. Exposure to PM2.5 can make cell membranes more permeable, making it easier for bacteria to share DNA that would give them immunity to certain antibiotics, according to lead author Hong Chen, of Zhejiang University in China.
The theory that this could accelerate the larger problem of antibiotic resistance has been met with some skepticism. But the University of Michigan study bolsters a growing body of research linking air pollution to neurological illnesses. In a 2022 study examining the cognitive health of women between 74 and 92 years old, USC researchers found the risk of dementia decreased by 14% in areas with the greatest PM2.5 reductions. In a 2020 study, researchers at UC Davis found evidence that exposure to traffic-related air pollution altered the brain development of rats.
Whether cognitive or cardiovascular, the wide-ranging health effects of PM2.5 have been attributed to oxidative stress — the physical toll from the body’s natural response to the entry of foreign objects, which can lead to inflammation.
The severity of oxidative stress depends on the type of PM2.5 a person is exposed to. In the Michigan study, scientists modeled PM2.5 pollution from traffic, agriculture, windblown dust, coal-fired power plants and various industrial emissions, among other sources.
Except for windblown dust, all other sources were correlated with higher dementia prevalence. Surprisingly, wildfires and farm dust had stronger ties to dementia prevalence than traffic pollution and coal combustion.
“When you inhale any sort of particle, you’re body is going to have some sort of immune response,” said Suzanne Paulson, a UCLA professor of atmospheric and oceanic sciences. “But composition matters because if you’re near the coast, you might be breathing sea salt, which is not that bad for your body to deal with.
Paulson examined PM2.5 across more than 50 locations in Los Angeles. Though vehicle exhaust was once the primary source of particulate pollution in the region, metal particles from brake and tire wear are now a significant and growing source of PM2.5, Paulson said.
It has surpassed tailpipe emissions in recent years, as evidenced by higher copper and iron concentrations. While this trend shows how much cleaner vehicle engines have become, it also underscores an emerging concern.
As a growing number of heavy electric vehicles hit the road, there could be an increase in metal particles from eroding brakes and tires — and these substances are more toxic than vehicle exhaust.
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Nasal vaccine for Alzheimer’s disease tested in first human trial
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According to The Centers for Disease Control and Prevention (CDC), “Dementia is not a specific disease, but is rather a general term for the impaired ability to remember, think, or make decisions that interfere with doing everyday activities.” The most common type of dementia is Alzheimer’s disease, though there are several types of dementia including frontotemporal dementia (FTD), dementia with Lewy bodies (DLB), and vascular dementia (VaD) to name a few. Globally, more than 50 million people have dementia, and an estimated 10 million new cases are reported each year. Projections show that the number of affected individuals will reach 82 million in 2030 and 152 million by 2050.
A dementia diagnosis comes after a series of tests of memory, problem-solving, and other cognitive abilities performed by a health care provider. Blood tests, brain scans, and physicals are carried out to help doctors figure out the underlying cause. Dementia is broken down into early, mid, and late stages, with a worsening of symptoms as the condition progresses.
The long-term effects of dementia can be difficult for both those affected and their caregivers, family, and friends, and can include a lack of family recognition, difficulty walking, and significant memory impairment. The afflicted person becomes completely dependent on others for care. Early diagnosis is especially important and can help with planning both at home, with preventive care and other measures such as reminders, and at work. It also enables dementia patients to access clinical trials and available therapies that may improve cognitive functioning and overall quality of life.
Neural Effects consulted the CDC’s list of warning signs for dementia and Alzheimer’s disease to review what adults should look for before seeking an official medical diagnosis. This list may also prove helpful for those who’ve noticed loved ones who are experiencing one or more early signs of dementia.
shurkin_son // Shutterstock
According to The Centers for Disease Control and Prevention (CDC), “Dementia is not a specific disease, but is rather a general term for the impaired ability to remember, think, or make decisions that interfere with doing everyday activities.” The most common type of dementia is Alzheimer’s disease, though there are several types of dementia including frontotemporal dementia (FTD), dementia with Lewy bodies (DLB), and vascular dementia (VaD) to name a few. Globally, more than 50 million people have dementia, and an estimated 10 million new cases are reported each year. Projections show that the number of affected individuals will reach 82 million in 2030 and 152 million by 2050.
A dementia diagnosis comes after a series of tests of memory, problem-solving, and other cognitive abilities performed by a health care provider. Blood tests, brain scans, and physicals are carried out to help doctors figure out the underlying cause. Dementia is broken down into early, mid, and late stages, with a worsening of symptoms as the condition progresses.
The long-term effects of dementia can be difficult for both those affected and their caregivers, family, and friends, and can include a lack of family recognition, difficulty walking, and significant memory impairment. The afflicted person becomes completely dependent on others for care. Early diagnosis is especially important and can help with planning both at home, with preventive care and other measures such as reminders, and at work. It also enables dementia patients to access clinical trials and available therapies that may improve cognitive functioning and overall quality of life.
Neural Effects consulted the CDC’s list of warning signs for dementia and Alzheimer’s disease to review what adults should look for before seeking an official medical diagnosis. This list may also prove helpful for those who’ve noticed loved ones who are experiencing one or more early signs of dementia.
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Nasal vaccine for Alzheimer’s disease tested in first human trial
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Forgetting recently learned information is one of the earliest signs of dementia. Name recall, as well as remembering important dates and events, becomes difficult for people in the early stages of dementia. Often they need to rely on memory aids, like wall calendars, sticky notes, digital reminders, or help from family members for things like taking medications at the correct time and arriving on the right date to appointments. Asking the same question several times or repeating stories is very common. While this sign is seen often in dementia, it is also a typical sign of aging as well as mild cognitive impairment, which can be, but is not always, an early warning indicator of Alzheimer’s disease. Memory loss may also be a sign of depression; B12 deficiency; kidney, brain, thyroid, or liver disorders; or a side effect of certain medications.
LightField Studios // Shutterstock
Forgetting recently learned information is one of the earliest signs of dementia. Name recall, as well as remembering important dates and events, becomes difficult for people in the early stages of dementia. Often they need to rely on memory aids, like wall calendars, sticky notes, digital reminders, or help from family members for things like taking medications at the correct time and arriving on the right date to appointments. Asking the same question several times or repeating stories is very common. While this sign is seen often in dementia, it is also a typical sign of aging as well as mild cognitive impairment, which can be, but is not always, an early warning indicator of Alzheimer’s disease. Memory loss may also be a sign of depression; B12 deficiency; kidney, brain, thyroid, or liver disorders; or a side effect of certain medications.
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Nasal vaccine for Alzheimer’s disease tested in first human trial
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An occasional mix-up while balancing a checkbook can be a common sign of aging. Losing track of monthly bills can be a more serious sign. An inability to concentrate or difficulty following a familiar recipe may warrant a doctor’s visit. Planning may become almost impossible for those in the earliest stages of dementia and indicates a deficit in executive functioning. Difficulties with problem-solving can also signal other health issues ranging from serious conditions like a brain tumor to less insidious conditions such as stress.
Phase4Studios // Shutterstock
An occasional mix-up while balancing a checkbook can be a common sign of aging. Losing track of monthly bills can be a more serious sign. An inability to concentrate or difficulty following a familiar recipe may warrant a doctor’s visit. Planning may become almost impossible for those in the earliest stages of dementia and indicates a deficit in executive functioning. Difficulties with problem-solving can also signal other health issues ranging from serious conditions like a brain tumor to less insidious conditions such as stress.
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Nasal vaccine for Alzheimer’s disease tested in first human trial
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Often in early dementia, the simplest tasks become increasingly difficult. While older people may have trouble with operating a computer or the settings on a television remote—and this can be a normal symptom of aging—those with dementia can’t perform daily tasks that were once a part of their routine. Getting dressed can become a major undertaking. The real difficulty actually comes with the sequence or order of doing things. Writing out the steps to tasks such as preparing a meal and leaving them in easily accessible places can be helpful.
Monkey Business Images // Shutterstock
Often in early dementia, the simplest tasks become increasingly difficult. While older people may have trouble with operating a computer or the settings on a television remote—and this can be a normal symptom of aging—those with dementia can’t perform daily tasks that were once a part of their routine. Getting dressed can become a major undertaking. The real difficulty actually comes with the sequence or order of doing things. Writing out the steps to tasks such as preparing a meal and leaving them in easily accessible places can be helpful.
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Nasal vaccine for Alzheimer’s disease tested in first human trial
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Often people in the early stages of dementia forget the time and even lose track of months and seasons. While many retired people may forget what day it is because they no longer go to work and live by a calendar, the sort of confusion surrounding time is much more severe in those with dementia. Losing track of where they are or how they got to certain places is common and should be investigated by a doctor. This type of confusion may be acute and occur suddenly or may happen over time. Those afflicted will often experience periods of confusion surrounding time and place and then revert to their old selves. Perception of time and time distortion are also issues for those struggling with dementia. They may believe they haven’t seen a loved one for months or years, when in fact it was only days ago.
Jacob L. // Shutterstock
Often people in the early stages of dementia forget the time and even lose track of months and seasons. While many retired people may forget what day it is because they no longer go to work and live by a calendar, the sort of confusion surrounding time is much more severe in those with dementia. Losing track of where they are or how they got to certain places is common and should be investigated by a doctor. This type of confusion may be acute and occur suddenly or may happen over time. Those afflicted will often experience periods of confusion surrounding time and place and then revert to their old selves. Perception of time and time distortion are also issues for those struggling with dementia. They may believe they haven’t seen a loved one for months or years, when in fact it was only days ago.
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Nasal vaccine for Alzheimer’s disease tested in first human trial
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Difficulty understanding visual images and spatial relations can impact depth perception, which can cause an increased risk of falling and can make feeding and bathing more challenging. Driving difficulty due to problems with spatial relations is quite common, and navigating turns and changing lanes can become dangerous. Often people with dementia are forced to give up driving. Reading also becomes a problem, not only because of the visuospatial issues, but also due to an inability to understand words. A 2016 study of visuospatial skills in dementia patients found that those with certain types of dementia, including Alzheimer’s disease, dementia of Lewy bodies, and vascular dementia, performed poorly in comparison to controls when examining space and object perception. The study found that significant impairment of visuospatial functions occurs in the early stages of dementia and worsens as the disease progresses.
photo8313 // Shutterstock
Difficulty understanding visual images and spatial relations can impact depth perception, which can cause an increased risk of falling and can make feeding and bathing more challenging. Driving difficulty due to problems with spatial relations is quite common, and navigating turns and changing lanes can become dangerous. Often people with dementia are forced to give up driving. Reading also becomes a problem, not only because of the visuospatial issues, but also due to an inability to understand words. A 2016 study of visuospatial skills in dementia patients found that those with certain types of dementia, including Alzheimer’s disease, dementia of Lewy bodies, and vascular dementia, performed poorly in comparison to controls when examining space and object perception. The study found that significant impairment of visuospatial functions occurs in the early stages of dementia and worsens as the disease progresses.
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Nasal vaccine for Alzheimer’s disease tested in first human trial
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While aging can cause an occasional problem with finding the right word, communication issues are much more significant in the early stages of dementia. Following conversations and finding the correct words for objects is difficult for those with dementia, and this early warning sign should be brought to a doctor’s attention. Aphasia, a type of language disorder, impacts communication including speech, writing, and language comprehension. According to the Mayo Clinic, “Primary progressive aphasia is a type of frontotemporal dementia.” Of course, there are other medical conditions that can cause language and communication issues including strokes, brain tumors, and brain injuries.
wavebreakmedia // Shutterstock
While aging can cause an occasional problem with finding the right word, communication issues are much more significant in the early stages of dementia. Following conversations and finding the correct words for objects is difficult for those with dementia, and this early warning sign should be brought to a doctor’s attention. Aphasia, a type of language disorder, impacts communication including speech, writing, and language comprehension. According to the Mayo Clinic, “Primary progressive aphasia is a type of frontotemporal dementia.” Of course, there are other medical conditions that can cause language and communication issues including strokes, brain tumors, and brain injuries.
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Nasal vaccine for Alzheimer’s disease tested in first human trial
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Misplacing things could mean putting objects in strange places, like placing car keys in the microwave, and it is a common sign of dementia. Those struggling may also have difficulty in retracing their steps to find the things they’ve lost. This lack of ability to retrace steps differentiates this as a sign of dementia versus a normal sign of aging. It can be both dangerous and frustrating. As the disease progresses, the afflicted person may accuse others of stealing things that have been misplaced.
CGN089 // Shutterstock
Misplacing things could mean putting objects in strange places, like placing car keys in the microwave, and it is a common sign of dementia. Those struggling may also have difficulty in retracing their steps to find the things they’ve lost. This lack of ability to retrace steps differentiates this as a sign of dementia versus a normal sign of aging. It can be both dangerous and frustrating. As the disease progresses, the afflicted person may accuse others of stealing things that have been misplaced.
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Nasal vaccine for Alzheimer’s disease tested in first human trial
Monkey Business Images // Shutterstock
During the early stages of dementia, decision-making is impacted and can cause poor judgment. People may spend money foolishly or have a hard time remembering to feed and walk a pet. They may also pay less attention to grooming and personal hygiene. Those struggling with dementia are especially susceptible to scams involving money. One poor decision should not be considered an indicator of dementia though. Instead, look for a pattern which might include things like constantly wearing summer dresses even though it’s winter, or walking in a busy area and not paying attention to traffic lights.
Monkey Business Images // Shutterstock
During the early stages of dementia, decision-making is impacted and can cause poor judgment. People may spend money foolishly or have a hard time remembering to feed and walk a pet. They may also pay less attention to grooming and personal hygiene. Those struggling with dementia are especially susceptible to scams involving money. One poor decision should not be considered an indicator of dementia though. Instead, look for a pattern which might include things like constantly wearing summer dresses even though it’s winter, or walking in a busy area and not paying attention to traffic lights.
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Nasal vaccine for Alzheimer’s disease tested in first human trial
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Not wanting to participate in social activities once enjoyed, like golf or going to church, may be a sign of dementia. Because of an inability to follow conversations or participate in hobbies and comprehend them in a familiar way, things like watching a favorite sport or going to family dinners might become less enjoyable. This may cause people with dementia to withdraw. They may sleep more frequently or spend more time sitting in front of the television. Social withdrawal could also be a symptom of depression, anxiety, or post-traumatic stress disorder.
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Not wanting to participate in social activities once enjoyed, like golf or going to church, may be a sign of dementia. Because of an inability to follow conversations or participate in hobbies and comprehend them in a familiar way, things like watching a favorite sport or going to family dinners might become less enjoyable. This may cause people with dementia to withdraw. They may sleep more frequently or spend more time sitting in front of the television. Social withdrawal could also be a symptom of depression, anxiety, or post-traumatic stress disorder.
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Nasal vaccine for Alzheimer’s disease tested in first human trial
Monkey Business Images // Shutterstock
While being sad or experiencing a shift in mood can happen to almost anyone occasionally, mood and personality changes may be early indicators of serious health issues. These can include mental health conditions, hormonal changes, or substance abuse problems. When those with dementia experience these symptoms, they can manifest as fear, suspicion, and getting easily upset or becoming irritable over minor things. Things that never would have bothered them before often will now. They may also lose patience more quickly. The National Institute on Aging recommends doing several things to help navigate these changes in mood and personality, including having a daily routine and using humor when appropriate.
This story originally appeared on Neural Effects and was produced and distributed in partnership with Stacker Studio.
Monkey Business Images // Shutterstock
While being sad or experiencing a shift in mood can happen to almost anyone occasionally, mood and personality changes may be early indicators of serious health issues. These can include mental health conditions, hormonal changes, or substance abuse problems. When those with dementia experience these symptoms, they can manifest as fear, suspicion, and getting easily upset or becoming irritable over minor things. Things that never would have bothered them before often will now. They may also lose patience more quickly. The National Institute on Aging recommends doing several things to help navigate these changes in mood and personality, including having a daily routine and using humor when appropriate.
This story originally appeared on Neural Effects and was produced and distributed in partnership with Stacker Studio.
