Exposure to Wildfire Smoke Greatly Raises Risk of Dementia Diagnosis

Posted on July 30, 2024 by Respro® UK Ltd

Key Takeaways

  • Wildfire smoke may be particularly hazardous to brain health, according to a 10-year study of more than 1.2 million southern Californians.
  • Exposure to wildfire smoke increases the risk of being diagnosed with dementia more than other forms of air pollution.
  • The risk of exposure to fine particulate matter (PM2.5) air pollution is much more pronounced when the source is wildfire smoke than when it comes from other sources, such as motor vehicles and factories.
  • To lower their risk, people should update their home air filtration systems when possible, stay inside when the air quality is unhealthy, and wear an N95 mask outside when the Air Quality Index reaches 100.

Exposure to wildfire smoke increases the risk of being diagnosed with dementia more than other types of air pollution, according to a decade-long study of more than 1.2 million people in southern California. The findings, reported today at the Alzheimer’s Association International Conference® (AAIC®) 2024, in Philadelphia and online, suggest the brain health threat posed by wildfire smoke is higher than other forms of air pollution.

Wildfire smoke, motor vehicles and factories all emit a type of air pollution called fine particulate matter (PM2.5). This is a microscopic mixture of solid and liquid droplets in the air that are 30 times smaller than the width of an average human hair. Researchers found that the risk of dementia diagnosis due to exposure to PM2.5 in wildfire smoke was notably stronger — even with less exposure — than the risk due to the other sources of PM2.5 air pollution. Exposure to non-wildfire PM2.5 raised the risk of dementia diagnosis, but not as much as wildfire smoke.

High levels of PM2.5 also have been shown to raise the risk of heart disease, asthma and low birth weight.

“With the rising global incidence of wildfires, including in California and the western U.S., exposure to this type of air pollution is an increasing threat to brain health,” said Claire Sexton, DPhil, Alzheimer’s Association senior director of scientific programs and outreach. “These findings underscore the importance of enacting policies to prevent wildfires and investigating better methods to address them.”

Researchers analyzed the health records of 1,227,241 socioeconomically diverse Kaiser Permanente southern California members who were 60 years or older between 2009-2019, none of whom had been diagnosed with dementia at the beginning of the study. Total PM2.5 was estimated from various sources, including satellite-derived aerosol properties and Environmental Protection Agency monitoring. Researchers used air quality monitoring data, satellite imagery and machine learning techniques to separate wildfire and non-wildfire PM2.5. They determined each study participant’s exposure to both sources of PM2.5 according to where they lived. They compared that information to subsequent diagnoses of dementia in participants’ health records.

Reported for the first time at AAIC 2024, the researchers observed a 21% increase in the odds of dementia diagnosis for every increase of 1 microgram per meter — or µg/m3, which is the amount of particulate matter in a cubic meter of air — in the three-year average wildfire PM2.5 exposure. Comparatively, they determined study participants had a 3% increased risk of dementia diagnosis for every increase of 3 µg/m3 in the three-year average of non-wildfire PM2.5 exposure.

“Previous research has found that exposure to PM2.5 is associated with dementia, but in light of our large, long-term study, it’s apparent the risk from exposure due to wildfire smoke is an even bigger concern,” said Holly Elser, M.D., Ph.D., the study’s first author and a neurology resident at the Hospital of the University of Pennsylvania, Philadelphia. “Air pollution produced by wildfires now accounts for more than 70% of total PM2.5 exposure on poor air quality days in California. This is a real problem.”

Dr. Elser noted several reasons why PM2.5 produced by wildfires might be more hazardous to health: they are produced at higher temperatures, contain a greater concentration of toxic chemicals and, on average, are smaller in diameter than PM2.5 from other sources. She said more research needs to be done to determine the exact mechanisms.

“The findings appeared most pronounced among individuals from racially and ethnically minoritized groups and in high poverty areas,” said Joan A. Casey, Ph.D., senior author of the study and assistant professor in the Department of Environmental and Occupational Health Sciences at the University of Washington, Seattle. “These findings underscore that clinical and health policies seeking to prevent dementia-associated disparities should include efforts to reduce exposure to long-term wildfire and non-wildfire PM2.5.”

Drs. Elser and Casey recommend that people update their air filtration systems and check the air quality on their weather app if they use one. An Air Quality Index (AQI) number of 100 or higher means the air is unhealthy to breathe. To reduce their risk when the AQI is 100 or higher, people should stay inside when possible and close the windows, and wear an N95 mask when they go outside.

Exposure to Wildfire Smoke Raises Risk of Dementia | alz.org

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Large-scale and intense wildfires carrying smoke across northern hemisphere

Posted on July 23, 2024 by Respro® UK Ltd

Late spring and early summer blazes in Canada, Alaska and eastern Russia add to carbon emissions


The northern hemisphere has had a large number of intense wildfires in the first half of summer, carrying vast amounts of smoke across Eurasia and North America.

Research by the Copernicus Atmosphere Monitoring Service (Cams) showed large-scale and intense wildfires had been developing throughout the late spring and summer, with numerous fires burning in Canada, Alaska and eastern Russia.

These wildfires are generally caused by long periods of hot and dry conditions in areas of high vegetation, and have resulted in increased carbon and smoke emissions. Smoke has also begun to extend much farther north, reaching across the Arctic Ocean to the high Arctic.

Emissions from Russian wildfires in June and July were higher than for the preceding two years, and fires in the region of Amur Oblast led to the estimated release of 17.2 megatonnes of carbon for the two-month period, the highest in 22 years.

Canada has also had some of its highest totals on record, with total carbon emissions of 11.1 megatonnes and 13.2 megatonnes for British Columbia and Alberta respectively across June and July.

Mark Parrington, a senior scientist at Cams, said: “We have been closely monitoring boreal fires in Cams over a number of years and noted some particularly extreme wildfire emissions and atmospheric impacts during that time, particularly in Canada, eastern Russia and the Arctic.”

Increasing wildfire activity is a major factor in these rising smoke emissions.

Guillermo Rein, a professor of fire science in the department of mechanical engineering at Imperial College London, said: “In recent years the fire season is expanding, starting earlier and lasting longer. But it’s not just the fact the wildfire season is widening, it’s also that the intensity of wildfire season is becoming unprecedented.”

According to official Russian figures, the number of wildfires this year has decreased by 30% compared with the previous year, but the area burnt is 50% larger, highlighting the intensity of the wildfires.

These increased smoke emissions have led to very high levels of air pollution and can lead to various health complications.

“In the short term, the most obvious complications are to respiratory systems, proving particularly dangerous for people that have underlying conditions like asthma, heart disease and lung disease,” says Dr Marina Romanello, a research fellow at the UCL Institute for Global Health.

“However, as the incidence of wildfires is increasing, people are being repeatedly exposed to acute levels of wildfire related air pollution, increasing their risk of developing chronic conditions like cardiovascular disease and cancer.”

Concentrations of very small harmful particulates in the smoke, known as PM2.5, have been found to be several times higher than the World Health Organization’s recommended 24-hour mean exposure threshold across a widespread region that includes eastern Mongolia, north-eastern China and northern Japan.

Romanello said: “PM2.5 particles are … able to go very deep into the lungs, past the lung-blood barrier, and enter the bloodstream, making these high levels of smoke emissions particularly concerning.”

While 2024’s estimated wildfire carbon emissions are very high so far, the season is still well short of the catastrophic 2023 season, when much of North America experienced record high levels of PM2.5.

Rein said: “We don’t think this season is going to break any records but it’s a strange situation where we’ve been seeing the worst in the records for so long that when you see it you think things are OK, when actually it’s still pretty bad.”

Large-scale and intense wildfires carrying smoke across northern hemisphere | Wildfires | The Guardian

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More Black Americans die from effects of air pollution, study shows

Posted on July 18, 2024 by Respro® UK Ltd

Everyone knows that air pollution is bad for health, but how bad depends a lot on who you are. People of different races and ethnicities, education levels, locations and socioeconomic situations tend to be exposed to different degrees of air pollution. Even at the same exposure levels, people’s ability to cope with its effects—by accessing timely health care, for example—varies.

A new study by Stanford Medicine researchers and collaborators, which takes into account both exposure to air pollution and susceptibility to its harms, found that Black Americans are significantly more likely to die from causes related to air pollution, compared with other racial and ethnic groups.

They face a double jeopardy: more exposure to polluted air along with more susceptibility to its adverse health effects because of societal disadvantages.

“We see differences across all factors that we examine, such as education, geography and social vulnerability, but what is striking is that the differences between racial-ethnic groups—partially due to our methodology—are substantially larger than for all of these other factors,” said Pascal Geldsetzer, MD, Ph.D., assistant professor of medicine and lead author of the study published July 1 in Nature Medicine.

The results demonstrate how air pollution can drive health inequities, contributing a large portion to the difference in mortality rates among different groups.

Yet, by the same token, the researchers say that reducing air pollution could be a powerful and achievable way to address these inequities.

Fine particles

Air quality throughout the U.S. has improved dramatically over the last few decades, thanks in large part to regulations such as the Clean Air Act, which sets limits on air pollutants emitted by industries and other sources.

Among the pollutants most linked to health, and the focus of the new study, is fine particulate matter, referred to as PM2.5 because it includes particles less than 2.5 micrometers in diameter. These particles are small enough to enter the bloodstream and affect vital organs.

“It’s very well recognized that PM2.5 is the biggest environmental killer globally,” said Tarik Benmarhnia, Ph.D., associate professor at the University of California, San Diego’s Scripps Institution of Oceanography and the senior author of the study.

Exposure to these fine particles can exacerbate asthma and chronic obstructive pulmonary disease in the short term, and in the long term contribute to heart disease, dementia, stroke and cancer.

In 1990, 85.9% of the U.S. population was exposed to average PM2.5 levels above 12 micrograms per cubic meter—the threshold set by the Environmental Protection Agency. In 2016, only 0.9% of the population was exposed to average levels above the threshold. (In February, the agency lowered the limit to 9 micrograms per cubic meter.)

Despite these significant improvements, not all communities have benefitted equally.

Benefits may vary

In the new study, the researchers wanted to see just how much PM2.5 levels contributed to mortality in people of different races and ethnicities, education, location (metropolitan or rural) and socioeconomic status.

They used existing county-level data on mortality along with census-tract-level data on PM2.5 air pollution and population from 1990 to 2016. They employed models derived from previous epidemiological studies, known as concentration-response functions, that linked certain deaths to air pollution levels. They chose a model that accounted for differences in susceptibility among racial and ethnic groups.

“Concentration-response functions are essentially saying, if you get exposed to this much more air pollution, then you would expect, on average, this much more risk of death,” Geldsetzer said.

Though deaths related to PM2.5 levels fell overall, some groups remained more affected than others. The researchers found higher rates of PM2.5-attributable mortality in people with less education; those living in large metropolitan areas; and those who were more socially vulnerable due to housing, poverty and other factors. People in the Mountain West states were less likely to die from PM2.5 pollution than people in other regions.

But the starkest disparities appeared when researchers sorted the data by race and ethnicity.

In 1990, the PM2.5-attributable mortality rate for Black Americans was roughly 350 deaths per 100,000 people, compared with less than 100 deaths per 100,000 people for each of the other races. By 2016, PM2.5-attributable mortality had fallen for all groups. Black Americans experienced the largest decline, to about 50 deaths per 100,000 people, yet were still the highest among all groups.

These relative trends were consistent throughout the country. In 96.6% of counties, Black Americans had the highest PM2.5-attributable mortality.

Among all the factors the researchers considered, race was the most influential in determining mortality risk from air pollution. They found that Black Americans have more exposure to air pollution, and its effects on mortality are amplified by factors such as poverty, existing medical conditions, more hazardous jobs, and lack of access to housing and health care.

Race and racism play into many of these amplifying factors, the researchers noted.

“Racism is an upstream driver of all these components of social inequality,” Benmarhnia said.

Taking action

“Air pollution is increasingly being recognized in public health as a cause of adverse health consequences that’s larger than people initially thought,” Geldsetzer said.

Harmful levels of PM2.5 can be imperceptible, but experienced day after day, year after year, they contribute to disease. And climate change means more wildfires (which produce particularly toxic fine particles) combined with extreme heat, increasing health risks.

“Even today there is a lot of resistance toward trying to reduce air pollution,” Benmarhnia said, citing the recent Supreme Court ruling against a plan to limit air pollution drifting across state lines.

Environmental policies should reduce air pollutants as much as possible, the researchers said, but also need to address the fact that some communities are more susceptible—something that major environmental organizations are not yet doing.

The silver lining is that the groups who suffer more from increasing air pollution would also benefit more from decreasing air pollution.

For every unit of reduction in PM2.5, for example, the associated mortality risk would decrease more for Black Americans than for other groups, helping close the racial gap.

“We want to emphasize how air pollution is a very good way to reduce health disparities, because it’s actionable,” Benmarhnia said. “We know we can do something about air pollution.”

More information: Pascal Geldsetzer et al, Disparities in air pollution attributable mortality in the US population by race/ethnicity and sociodemographic factors, Nature Medicine (2024). DOI: 10.1038/s41591-024-03117-0

Journal information: Nature Medicine 

More Black Americans die from effects of air pollution, study shows

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Chronic exposure to air pollutants may increase lupus risk, research shows

Posted on July 11, 2024 by Respro® UK Ltd

New research published in Arthritis & Rheumatology indicates that chronic exposure to air pollutants may increase the risk of developing lupus, an autoimmune disease that affects multiple organs.

For the study, investigators analyzed data on 459,815 participants from the UK Biobank. A total of 399 lupus cases were identified during a median follow-up of 11.77 years. Air pollutant exposure was linked with a greater likelihood of developing lupus. Individuals with a high genetic risk and high air pollution exposure had the highest risk of developing lupus compared with those with low genetic risk and low air pollution exposure.

“Our study provides crucial insights into the air pollution contributing to autoimmune diseases. The findings can inform the development of stricter air quality regulations to mitigate exposure to harmful pollutants, thereby reducing the risk of lupus.” – Yaohua Tian, PhD, co-corresponding author of the Huazhong University of Science and Technology, in China

Chronic exposure to air pollutants may increase lupus risk, research shows

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Air pollution linked to a decrease in IVF birth rate success, new study shows

Posted on July 8, 2024 by Respro® UK Ltd

A pioneering study, presented at the ESHRE 40th Annual Meeting in Amsterdam, has revealed that exposure to fine particulate matter (PM) prior to the retrieval of oocytes (eggs) during in vitro fertilization (IVF) can reduce the odds of achieving a live birth by almost 40%.

The study analyzed PM10 exposure in the two weeks leading up to oocyte collection, finding that the odds of a live birth decreased by 38% (OR 0.62, 95% CI 0.43–0.89, p=0.010) when comparing the highest quartile of exposure (18.63 to 35.42 µg/m3) to the lowest quartile (7.08 to 12.92 µg/m3). The study abstract was published in Human Reproduction.

Conducted over an eight-year period in Perth, Australia, the research analyzed 3,659 frozen embryo transfers from 1,836 patients. The median female age was 34.5 years at the time of oocyte retrieval and 36.1 years at the time of frozen embryo transfer.

The study examined air pollutant concentrations over four exposure periods prior to oocyte retrieval (24 hours, two weeks, four weeks, and three months), with models created to account for co-exposures.

Increasing PM2.5 exposure in the three months prior to oocyte retrieval was also associated with decreased odds of live birth, falling from 0.90 (95% CI 0.70–1.15) in the second quartile to 0.66 (95% CI 0.47–0.92) in the fourth quartile.

Importantly, the negative impact of air pollution was observed despite excellent overall air quality during the study period, with PM10 and PM2.5 levels exceeding WHO guidelines on just 0.4% and 4.5% of the study days, respectively.

Dr. Sebastian Leathersich, lead author of the study, explains, “This is the first study that has used frozen embryo transfer cycles to separately analyze the effects of pollutant exposure during the development of eggs and around the time of embryo transfer and early pregnancy. We could therefore evaluate whether pollution was having an effect on the eggs themselves, or on the early stages of pregnancy.”

“Our results reveal a negative linear association between particulate matter exposure during the two weeks and three months prior to oocyte collection and subsequent live birth rates from those oocytes. This association is independent of the air quality at the time of frozen embryo transfer.

“These findings suggest that pollution negatively affects the quality of the eggs, not just the early stages of pregnancy, which is a distinction that has not been previously reported.”

Ambient (outdoor) air pollution is one of the greatest environmental risks to health and is estimated to cause over 4 million premature deaths per year worldwide. Exposure to fine particulate matter is associated with a range of adverse health conditions, including cardiovascular and respiratory diseases.

In 2021, 97% of the urban EU population was exposed to concentrations of PM2.5 above the WHO annual guideline (5 µg (microgram) /m3). Although epidemiological data show a clear correlation between pollution and poorer reproductive outcomes, the mechanisms remain unclear.

Dr. Leathersich explains, “Climate change and pollution remain the greatest threats to human health, and human reproduction is not immune to this. Even in a part of the world with exceptional air quality, where very few days exceed the internationally accepted upper limits for pollution, there is a strong negative correlation between the amount of air pollution and the live birth rate in frozen embryo transfer cycles. Minimizing pollutant exposure must be a key public health priority.”

Professor Dr. Anis Feki, Chair-Elect of ESHRE, comments, “This important study highlights a significant link between air pollution and lower IVF success rates, with a notable reduction in live births associated with higher particulate matter exposure before oocyte retrieval. These findings emphasize the need for ongoing attention to environmental factors in reproductive health.”

Air pollution linked to a decrease in IVF birth rate success, new study shows

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Study reveals fireworks’ impact on air quality

Posted on July 3, 2024 by Respro® UK Ltd

As Independence Day approaches, Utahns are preparing to celebrate the nation’s birth with dazzling displays of light and color. However, a new BYU study published in Applied Geochemistry warns that these festivities come with an often-overlooked hazard: increased air pollution.

The study, led by BYU geology professor Greg Carling, reveals alarming details about the particulate matter that is released into the air when fireworks explode.

Particulate matter is a mixture of microscopic pieces of dust, trace metals, smoke, liquid droplets and other pollutants. Small particles such as PM2.5 pose the greatest threat to human health because they are easily inhaled and can get deep into the lungs.

Carling’s research notes that the largest contributors of particulate matter along the Wasatch Front are mineral dust, winter inversion and Utah’s beloved fireworks.

“We know we’re breathing in these particles that are unhealthy during firework events, dust storms, or winter inversions,” said Carling. “But what’s actually in the particulate matter? No one really knew before this study.”

Over two years, Carling and students monitored air samplers with filters collecting various sizes of particulate matter, including the notorious health hazard PM2.5. They measured the concentration of trace metals in particulate matter over time.

Their findings show that metal pollution in particulate matter peaks during January and July, coinciding with winter inversions and summer fireworks. Fireworks emit high levels of barium and copper, while arsenic, cadmium, lead, and thallium were prevalent in the inversion smog.

Prolonged exposure to these substances can cause various health problems, ranging from asthma to cardiovascular disease. Despite strict drinking water standards in Utah, similar air quality standards for these metals do not currently exist.

“We know a bit about the acute problems that elements such as lead cause,” said Carling. “But then there are the chronic problems we don’t know about, and that probably should make people think, “Oh, so what’s actually harmful and how do we figure out what’s harmful?'”

Carling emphasized that any concentration of particulate matter is hazardous to human health and the environment. “Metals are really good at moving around from the atmosphere into the soil, into the water and into our food,” warned Carling. “And they’re persistent, meaning that they don’t really go away—they just keep cycling through the system.”

Any firework that produces smoke or colored light significantly contributes to Utah’s air pollution, particularly given the two major firework holidays in July.

But Carling is optimistic that increased awareness will lead to better decision-making and solutions. He recommends that individuals take advantage of city firework displays and avoid personal pyrotechnic shows. Exercising indoors during periods of poor air quality or getting away from the city can reduce the amount of toxins breathed in.

Additionally, Carling’s research can be utilized by policymakers to limit the types and quantities of fireworks used and to support further research into the health effects of trace metal pollution.

“It’s great when research leads toward legislation that can help improve things,” stated Carling. “Sometimes it’s just a paper that gets published and a few scientists read it. But other times, it gets picked up and used to create real solutions.”

Study reveals fireworks’ impact on air quality

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Ultrafine particles from planes put 52 million Europeans at risk of serious health conditions

Posted on June 25, 2024 by Respro® UK Ltd

A new study by green group Transport & Environment (T&E) suggests that thousands of cases of high blood pressure, diabetes and dementia across Europe could be linked to the tiny particles emitted by planes.

52 million people – more than 10% of Europe’s total population – live within a 20km radius from the 32 busiest airports in Europe and are particularly exposed to ultrafine particles from aviation, new research by CE Delft and commissioned by T&E finds [1],[2]. In Paris, one of the cities included in the study, 8 million people are affected by its two main airports Charles de Gaulle and Orly. The exposure to ultrafine particles can be linked to the development of serious and long-term health conditions, including respiratory problems, cardiovascular effects and pregnancy issues.

Exposure to ultrafine particles may be associated with 280,000 cases of high blood pressure, 330,000 cases of diabetes, and 18,000 cases of dementia in Europe, according to the new research. The study extrapolated reported cases of these illnesses around Amsterdam Schiphol airport and gives the first ever estimate of health effects linked to aviation-related UFPs in Europe.

Ultrafine particles are particularly concerning because they penetrate deeply into the human body and have been found in the blood, brain and placenta. UFPs are below the size of 100 nanometres in diameter – approximately 1,000 times smaller than a human hair. To date, there is no regulation on safe levels of UFPs in the air, even though the WHO warned it was a pollutant of emerging concern over 15 years ago.

UFPs from planes are emitted at high altitude but also at take-off and landing meaning residents living near airports are particularly affected. People living in a 5km radius from an airport breathe in air that contains, on average, anything from 3,000 to 10,000 ultrafine particles per cm3 emitted by aircraft. In many cities, a correlation exists between people living near an airport and lower incomes. This shows once again that the most vulnerable in society are most affected by air pollution.

Jemima Hartshorn, founder of Mums for Lungs, a UK-based campaign group on air pollution, “First we had the problem of air pollution from roads, then we had wood burning stoves, and now we are becoming aware of another invisible danger affecting everyone’s health. We know that air pollution is the biggest public health crisis and particularly affects children, babies and older people. These tiny particles are known to penetrate every organ of the body, including the placenta. Most people have no choice over where airports are sited or how big they are, and often this pollution is being created by planes carrying passengers from all around the world”.

Using ‘better quality’ jet fuel, though, can reduce UFPs by up to 70%, the study finds. The amount of UFPs emitted from planes depends largely on the composition of the fuel. The cleaner the aviation fuel, the less pollution it generates when burnt. Cleaning this fuel happens through a process called hydrotreatment [3]. It has been used for decades to remove sulphur from fuels for cars and ships fuels and could cost less than five cents per liter of fuel. But jet fuel standards for planes have never been improved, even though it can significantly reduce air pollution around airports.

Other measures to reduce UFPs and improve air quality include reducing air traffic and aviation’s exponential growth, as well as using cleaner technologies like sustainable aviation fuels (SAFs) and zero-emission aircraft that release much fewer pollutants.

“It’s not often that an alarming problem affecting millions of people can be reduced, and at a low cost. Dirty fumes caused by planes can be drastically reduced if we clean up the fuel. The sector prides itself with cutting-edge technology and so-called efficient planes, yet continues to use fuels which have a devastating impact on the health of millions of Europeans. It’s time for the EU to set jet fuel quality standards for the sake of the climate and people’s health”, Carlos Lopez de la Osa, aviation technical manager at T&E, concludes.

UFPs are part of the so-called “non-CO2 emissions” from planes, which include many other toxic pollutants, both gases and particles, such as nitrogen oxides and sulphur dioxide. Although these pollutants do not fall within the scope of the study, they also have known health effects that add to the ones previously described. These emissions also have a harmful effect on climate, making aviation’s contribution to global warming at least twice as bad as commonly thought. For example, the formation of contrails – the white lines criss-crossing the sky behind planes, with a significant warming effect – is also related to UFP emissions. Reducing UFP emissions through better quality jet fuel would not only be beneficial for the population living near airports, but also for the planet.

Ultrafine particles from planes put 52… | Transport & Environment
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Study suggests that air pollution promotes inflammation in the brain, accelerating consequences for dementia

Posted on May 20, 2024 by Respro® UK Ltd

Levels of air pollution and road traffic noise levels of nurses from the Danish Nurse Cohort at the cohort baseline aggregated at the municipality level. Credit: Alzheimer’s & Dementia (2024). DOI: 10.1002/alz.13814

Results from a new study suggest that long-term exposure to air pollution leads to increased risk in dementia in Denmark.

“We also find association with noise, but this seems to be explained by air pollution primarily. Our study is in line with growing international knowledge on this topic,” says Professor at Section of Environmental Health Zorana Jovanovic Andersen.

This is an important finding that adds that air pollution, beyond well-known effects on respiratory and cardiovascular system, also has major impacts on our brain, promoting inflammation in the brain, accelerating cognitive decline, and increasing risk of dementia.

“This is the first study in Denmark showing a link between air pollution and dementia. Although air pollution levels in Denmark have been declining and are relatively low, compared of the rest of Europe and world, this study shows that there are still significant and concerning health effects that demand more action and policies towards reduction of air pollution.

“As we are going to live longer, and more and more people will be diagnosed with dementia, this finding is important as it offer an opportunity to prevent new dementia cases, and ensure more healthy aging, by cleaning up the air we breathe,” says Andersen.

The study followed a cohort of nurses for 27 years, from 1993 until 2020.

“This is internationally unique and necessary in regards of the development of dementia which can take many years. Second, the air pollution was estimated for each participant for a total of 41 years (from 1979 until 2020), which is also incredible. Third, we had extensive details about participant’s lifestyle and socio-economics and all our result take them in consideration.

“The novelty of this study is the very detailed and accurate data that we used,” says Research Assistant from Section of Environmental Health Stéphane Tuffier.

“Nurses with higher physical activity had a lower risk of dementia when exposed to air pollution compared to nurses with less physical activity. This indicates that physical activity might mitigate the adverse effects of air pollution on cognitive decline and risk of dementia,” Tuffier says.

More information: Stéphane Tuffier et al, Long‐term exposure to air pollution and road traffic noise and incidence of dementia in the Danish Nurse Cohort, Alzheimer’s & Dementia (2024). DOI: 10.1002/alz.13814

Journal information: Alzheimer’s & Dementia 

Provided by University of Copenhagen 

Study suggests that air pollution promotes inflammation in the brain, accelerating consequences for dementia

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