Over the years, two patients have visited the Penn Memory Center at the University of Pennsylvania. There, researchers and doctors tracked people whose cognitive abilities declined as they aged and a group with normal cognitive abilities.
Both male and female patients agreed to donate their brains for research. “It’s an amazing gift.” said Dr. Edward Lee, neuropathologist and hospital director. brain bank from the University’s Perelman School of Medicine. “They have been very committed to helping us understand Alzheimer’s disease.”
The man, who died of dementia at age 83, lived with a hired caregiver in Philadelphia’s Center City neighborhood. An autopsy showed large amounts of amyloid plaques spread throughout his brain and tau tangles, a protein associated with Alzheimer’s disease.
Investigators also found infarcts, small dots of damaged tissue, indicating he had suffered multiple strokes.
On the other hand, the woman who died of brain cancer at age 84 “had almost no signs of Alzheimer’s disease,” Lee said. “We tested him every year and there were no cognitive issues whatsoever.”
The man lived a few blocks from Highway 676, which runs through downtown Philadelphia. A woman who lives a few miles away in the suburb of Gladwayne, surrounded by forests and country clubs.
The amount of air pollution she was exposed to, specifically the level of fine particles known as PM2.5, was less than half of the air pollution the man was exposed to. Was it a coincidence that he developed severe Alzheimer’s disease and she maintained normal cognitive ability?
Probably not, given growing evidence that chronic exposure to the neurotoxin PM2.5 not only damages the lungs and heart, but is also linked to dementia.
“The quality of the air you live in affects your cognition,” said the study’s lead author. Recent articles published in JAMA NeurologyIt is one of several large studies published in recent months showing a link between PM2.5 and dementia.
Scientists have been studying this connection for at least 10 years. Influential in 2020 Lancet Commission The Lancet Commission included air pollution in its list of modifiable risk factors for dementia, along with common problems such as hearing loss, diabetes, smoking and high blood pressure.
These findings come at a time when the federal government is dismantling steps taken by previous administrations to reduce air pollution by switching from fossil fuels to renewable energy sources.
“‘Drill, baby, drill’ is completely the wrong approach,” said Dr. John Balmes, a spokesperson for the American Lung Association and a researcher on the health effects of air pollution at the University of California, San Francisco.
“All of these decisions will degrade air quality and increase mortality and disease. Dementia is one of those consequences,” Balmes added, referring to environmental measures recently adopted by the White House.
Of course, there are various factors that cause dementia. However, there is growing interest in the role of particles, which are solids or tiny water droplets in the air.
These particles come from a variety of sources, including emissions from power plants and residential heating, industrial gases, vehicle exhaust, and smoke from wildfires.
Among the various particle sizes, PM2.5 is one of the smallest and therefore “seems to be the most harmful to human health,” Lee said. It is easily inhaled and enters the bloodstream, where it circulates throughout the body. It can also travel directly from the nose to the brain.
The University of Pennsylvania study, the largest autopsy study of dementia patients, included more than 600 brains donated over a 20-year period.
Previous studies on the relationship between pollution and dementia were mainly based on epidemiological studies. Now, “we are linking exposure to pollutants with what we actually see in the brain,” Lee explained. “We’re going deeper.”
Study participants underwent several years of cognitive testing at the Penn Memory Center. Using environmental databases, researchers were able to calculate exposure to PM2.5 based on home address.
Scientists have also developed a matrix to measure the severity of brain damage from Alzheimer’s disease and other dementias.
Professor Lee’s team concluded, “The greater the exposure to PM2.5, the greater the risk of developing Alzheimer’s disease.” The odds of finding more severe Alzheimer’s disease at autopsy were nearly 20% higher among people living in areas with high PM2.5 levels.
Another research team recently reported: connection Between PM2.5 exposure and Lewy body dementia, including dementia associated with Parkinson’s disease. Lewy body dementia, generally considered the second most common type after Alzheimer’s disease, accounts for approximately 5 to 15 percent of cases.
In the study, considered the largest epidemiological study of pollution and dementia to date, researchers analyzed records for more than 56 million beneficiaries of the traditional Medicare program from 2000 to 2014, comparing the number of first hospitalizations for neurodegenerative diseases with PM2.5 levels by zip code.
“Chronic exposure to PM2.5 was associated with hospitalization for Lewy body dementia,” said Xiao Wu, an author of the study and a biostatistician at Columbia University’s Mailman School of Public Health.
After controlling for socioeconomic differences and other factors, the researchers found that PM2.5 hospitalization rates were 12 percent higher in U.S. counties with the lowest PM2.5 concentrations compared to counties with the lowest.
To confirm their findings, the researchers administered PM2.5 intranasally to mice, and after 10 months, the mice showed “clear dementia-like defects.” lead author Xiaobo Mao, a neuroscientist at Johns Hopkins University School of Medicine, wrote in an email.
The mouse got lost in a maze that had previously been easy to navigate. Before they build their nests quickly and orderly; After the exhibition they carried out their work in a careless and disorganized manner. Mao said autopsies showed their brains had atrophied and had accumulated alpha-synuclein protein, which is associated with Lewy bodies in the human brain.
third analysispublished this summer lanceThirty-two studies conducted in Europe, North America, Asia and Australia were included. They also found that “diagnosis of dementia was significantly associated with long-term exposure to PM2.5 and certain other pollutants.”
Whether outdoor air pollution, or environmental pollution, increases dementia risk through inflammation or other physiological mechanisms is a question that still requires further research.
Even though air pollution has declined in the United States over the past two decades, scientists are calling for more stringent policies to encourage cleaner air. “People say improving air quality is expensive,” Lee said. “The same goes for caring for people with dementia.”
However, President Donald Trump returned to power with the following pledge: Increase extraction and use of fossil fuels.This is slowing down the transition to renewable energy. your administration remove tax incentives Balmes added that in the case of solar installations and electric vehicles, “they are encouraging the continued burning of coal to generate energy.”
Even the government halted new offshore wind energy projectsadvertisement oil drilling gas into the Alaska Arctic National Wildlife Refuge and steps have been taken to stop it. california’s plan Switch to electric vehicles by 2035. (The state challenged the suit in court.)
Dr. Wu warned, “If policies go in the opposite direction as air pollution increases, this could pose a major risk to the health of older people.”
Last year, during the Biden administration, the Environmental Protection Agency (EPA) Annual standards were set More stringent standards for PM2.5 “Available scientific evidence and technical information indicates that current standards may not be adequate to protect public health and welfare as required by the Clean Air Act.”
In March New EPA Director The agency announced it would “reevaluate” its more stringent standards.
New Old Age is produced in partnership with: new york times.
