Dirty Air Is Deadly, Global Study Confirms

Serena Gordon wrote . . . . . . . . .

Air pollution — especially the fine particles that you breathe into your lungs — can shorten your life, a global study reports.

The new research found that short-term exposure to air pollution upped the daily risk of death from all causes. The risk of dying from heart disease, stroke and lung disease also rose with exposure to fine particle air pollution.

Particulate matter (PM) pollution is fine particles in the air. PM pollution can be found in various sizes. PM10 refers to particle matter between 2.5 micrometers and 10 micrometers large. That’s smaller than the width of a single hair. Particles this size are produced during industrial crushing or grinding, or as dust stirred up by vehicles, the U.S. Environmental Protection Agency says.

Smaller particles — PM2.5 — are less than 2.5 micrometers in size. These particles result from all types of combustion. Possible sources include motor vehicles, power plants, residential wood burning, forest fires, agricultural burning and some industrial processes. These particles are about 30 times smaller than the width of a single human hair, the EPA notes.

The study “found that on average, an increase in 10 micrograms per meter squared in inhalable PM10 and fine particles (PM2.5) is associated with an increase of 0.36% and 0.68% in daily mortality,” said study author Antonio Gasparrini.

That might not sound like much. But in a group of 15,000 people, it would translate to about 54 extra deaths related to PM10, and 102 associated with PM2.5 pollution, said Gasparrini, an associate professor of biostatistics and epidemiology at the London School of Hygiene and Tropical Medicine in England.

He explained that while the risk for any one individual is low, it’s worrisome at the population level.

“The main message [from the study] is about the risk associated with pollution and the importance of air quality standards and limits,” Gasparrini said, adding: “There is a substantial excess mortality that occurs with pollution levels below the current limits, which should, therefore, be tightened, not relaxed.”

The study compared daily data on air pollution and mortality for 652 cities from 24 countries or regions. Researchers controlled the data to account for gaseous pollutants.

The findings were published in the New England Journal of Medicine.

The author of an accompanying editorial, Dr. John Balmes, said the study was “important, though not groundbreaking.” He said it’s well-known that particulate matter pollution is linked to poor health outcomes.

The strength of this study is its large size and global data, said Balmes, a professor of environmental health sciences at the University of California, Berkeley, and a professor of medicine at University of California, San Francisco.

Like other studies on PM pollution, this one cannot definitively show a cause-and-effect relationship.

But Balmes likened it to the association between smoking and lung cancer. It would be unethical to do a study that definitively proves smoking causes lung cancer, because researchers would have to expose people to enough smoke to cause the disease. Yet doctors don’t question the link between smoking and lung cancer.

Likewise, with air pollution, to definitively prove the link, you would need to deliberately expose people to PM pollution. But Balmes said this study and many that have come before it make the link clear.

Particles from pollution deposit in the lungs where they likely cause injury and inflammation, he said. That inflammation then triggers a response throughout the body that can increase the risk of hardening in the blood vessels, which can lead to a heart attack and other serious health concerns.

So, what can be done to reduce the risk of death from particulate matter pollution? Gasparrini said the best way is to adopt specific policies to reduce pollution levels.

“These include, among others, technological developments to reduce emission from traffic and cleaner energy production,” he said. “This has been done successfully in the last decades, in particular in the United States.”

But that may be changing. The Trump administration has proposed rolling back some clean air regulations from the Obama era and even earlier. The proposed changes would likely add pollution and greenhouse gases into the environment, according to published reports. Twenty-nine states are suing to block some of these changes.

Balmes said some areas in the United States are taking matters into their own hands. An example is California, a leader in cleaner air regulations and clean energy sources that also has a booming economy, he said.

“The public needs to realize that air pollution is an important risk factor for public health. We’ve made changes, but we can get cleaner air yet. The co-benefit of cleaner energy and transportation changes for public health is a benefit in terms of climate change, too,” he said.

Source: HealthDay


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Vehicle Exhaust Pollutants Linked to Near Doubling in Risk of Age Related Macular Degeneration

Long term exposure to pollutants from vehicle exhaust is linked to a heightened risk of the common eye condition age-related macular degeneration, or AMD for short, suggests research published online in the Journal of Investigative Medicine.

Exposure to the highest levels of air pollutants was associated with an almost doubling in risk among those aged 50 and older, the findings show.

AMD is a neurodegenerative condition that affects the middle part of the retina, known as the macula. It is one of the most common causes of poor vision in older people, and is most likely caused by an interplay between genetic and environmental risk factors.

Long term exposure to air pollution has been linked to a heightened risk of several conditions, including respiratory and cardiovascular diseases. But less is known about its potential effects on eye health.

To explore this further, the Taiwanese researchers analysed national health insurance and air quality data from 1998 to 2010 to see if there might be a link between long term exposure to the pollutants nitrogen dioxide (NO?) and carbon monoxide (CO) and a heightened risk of AMD.

As the condition is more common among older age groups, the researchers focused only on 39,819 people aged 50 and above, most of whom lived in either highly (30%) or moderately (32.5%) urbanised areas.

Because there are seasonal variations in air pollutant levels, the researchers calculated an average annual exposure, which was categorised into four different levels.

During the monitoring period, 1442 people developed AMD.

After taking account of potentially influential factors, such as age, sex, household income, and underlying illnesses, those with the highest level of exposure to NO? (more than 9825.5 ppb) were nearly twice (91%) as likely to develop AMD as those exposed to the lowest level (less than 6563.2 ppb).

And people who were exposed to the highest level of CO (more than 297.1 ppm) were 84% more likely to develop AMD than those exposed to the lowest level (less than 195.7 ppm).

The highest rate (5.8%) of newly diagnosed AMD was among people living in the area with the highest level of CO exposure.

This is an observational study, and as such, can’t establish cause. And the authors emphasise that the data didn’t include information on other risk factors, such as smoking, genetics, and inflammation.

This is the first study of its kind to “demonstrate a significant association between AMD and high levels of ambient NO? and CO,” they write.

Recent research has implicated NO? in cardiovascular and neurological ill health, and as the retina is part of the central nervous system, there is a plausible biological explanation for its vulnerability to this pollutant, they add.

Source: Science Daily


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Why Polluted Air May Be a Threat to Your Kidneys

Jessie Fidler wrote . . . . . . . . .

There is good evidence that polluted air increases the risk of respiratory problems such as asthma — as well as organ inflammation, worsening of diabetes and other life-threatening conditions.

But new research suggests air pollution can also fuel something else: chronic kidney disease, or CKD, which occurs when a person’s kidneys become damaged or cannot filter blood properly.

Recently published in PLOS One, a University of Michigan study highlights the lesser-known connection.

“Similar to smoking, air pollution contains harmful toxins that can directly affect the kidneys,” says Jennifer Bragg-Gresham, M.S., Ph.D., a Michigan Medicine epidemiologist and the study’s lead author.

“Kidneys have a large volume of blood flowing through them, and if anything harms the circulatory system, the kidneys will be the first to sense those effects.”

People with diabetes, obesity, high blood pressure or heart disease are at increased risk of developing CKD. Which is why high-risk patients who live in heavily populated or polluted areas should recognize the danger and take precautions, Bragg-Gresham says.

Why air pollution is dangerous

Air pollution contains fine particulate matter, or PM2.5, which is a cocktail of microscopic particles.

Because these particles are virtually weightless, they can stay in the air longer, causing humans to unavoidably inhale them on a regular basis without knowing it. PM2.5 can lead to serious health effects when inhaled often.

By reviewing Medicare claims data and air-quality data from the Centers for Disease Control and Prevention, the study’s authors found a positive association between CKD rates and PM2.5 concentration.

Says study co-author Rajiv Saran, M.D., a Michigan Medicine nephrologist and director of the United States Renal Data System Coordinating Center at U-M: “If you look at areas that are heavily polluted versus areas that are less polluted, you will find more chronic kidney disease.”

According to figures cited in the new research, chronic kidney disease afflicts more than 27 million Americans. People with CKD have an eightfold increased risk of cardiovascular mortality.

Unfortunately, PM2.5 is almost impossible to avoid.

We encounter air pollution from many simple everyday activities, such as cooking and driving. Other contributors are smoking, burning wood, packaged spray products, household appliances and, perhaps the most obvious, industry and vehicle emissions.

Air pollution also contains heavy metals such as lead, mercury and cadmium — all of which are known to negatively affect the kidneys.

Problems and preventive measures

The U-M research examined several prior studies on the issue, including an effort conducted in select coal-mining areas of Appalachia that found a 19 percent higher risk of CKD among men and a 13 percent higher risk in women compared with those who lived in counties with no mining.

The good news: PM2.5 levels are much lower in the U.S. than in other industrialized countries such as China and India.

“What this means for the countries with higher PM2.5 is significantly higher odds of CKD,” says Bragg-Gresham, also an assistant research scientist at U-M. “Our research was only able to examine a small range of PM2.5 values present in America but was able to find a significant association.”

However, it’s still important to take precautions when exposed to air pollution, especially for people who have existing health conditions or who live in densely populated or polluted cities.

“In heavily polluted areas, consider wearing masks that cover your nose and mouth, limit hours outside and limit long hours commuting to work in high traffic as well,” Saran says, adding that the risk should be taken seriously.

“Many people don’t see the seriousness of air pollution because it isn’t something visible, but that doesn’t mean it’s any less important for your health.”

Source: University of Michigan


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Poor Air Quality Does Not Offset Exercise’s Heart Benefits

Even in areas with moderate-to-high levels of traffic pollution, regular physical activity reduced the risk of first and recurrent heart attack, according to new research in Journal of the American Heart Association, the Open Access Journal of the American Heart Association/American Stroke Association.

“While exercise is known to reduce cardiovascular disease risk; pollution can increase the risk of cardiovascular disease, including heart attacks, asthma and chronic obstructive lung disease,” said Nadine Kubesch, Ph.D., lead author and researcher at the University of Copenhagen in Denmark. “Currently there is little data on whether poor air quality cancels out the protective benefits of physical activity in preventing heart attacks.”

Researchers in Denmark, Germany and Spain evaluated outdoor physical activity levels (sports, cycling, walking and gardening) and nitrogen dioxide (NO2 pollutant generated by traffic) exposure in 51,868 adults, age 50-65, comparing self-reported activities and lifestyle factors against heart attack. Over a 17.7-year period, there were 2,936 first heart attacks and 324 recurrent heart attacks.

To estimate average NO2 exposure, researchers used national traffic pollution monitoring data for each participants’ address and found:

  • Higher levels of were associated with more heart attacks, however, the risk was lower among those who were physically active.
  • Moderate cycling for four or more hours per week cut risk for recurrent heart attack by 31 percent; and there was a 58 percent reduction when all four types of physical activity (together totalling four hours per week or more) were combined, regardless of air quality.
  • Those who participated in sports had a 15 percent lower rate of initial heart attacks and there was a 9 percent risk reduction associated with cycling, regardless of air quality
  • Compared to participants with low residential NO2 exposure, those in higher risk areas had a 17 percent increase risk in first heart attack and 39 percent for recurrent heart attack.

In particiants who developed a heart attack (first or recurrent), the average NO2 exposure level was 18.9 microgramm per cubic meter air (μg/m3) with an overall average of 18.7 μg/m3, which is below the current NO2 European Union exposure guideline (50 μg/m3 over 24 hours).

“Our study shows that physical activity even during exposure to air pollution, in cities with levels similar to those in Copenhagen, can reduce the risk of heart attack,” Kubesch said. “Our research supports existing evidence that even moderate levels of regular physical activity, such as active commuting, are suffienciently intense to get these health benefits.

Source: American Heart Association


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Air Pollution May Account for 1 in 7 New Diabetes Cases Worldwide

Anne Harding wrote . . . . . . .

Air pollution could be responsible for 3.2 million new cases of type 2 diabetes every year globally, suggests a new analysis.

“We estimate that about 14 percent of diabetes in the world occurs because of higher levels of air pollution, that’s one in seven cases,” said senior study author Dr. Ziyad Al-Aly of Washington University and the VA Saint Louis Health Care System in Missouri.

“Risks exist at levels that are below what’s now currently considered safe by the Environmental Protection Agency (EPA) in the United States and also by the World Health Organization,” he told Reuters Health in a phone interview.

The tiniest form of particulate matter pollution, known as PM 2.5, is already associated with increased risk of heart disease, lung disease, kidney disease, and other noncommunicable diseases “and contributed to about 4.2 million premature deaths in 2015,” the study team writes in The Lancet Planetary Health.

PM 2.5 is the mix of solid fragments and liquid droplets suspended in air that’s sometimes visible to human eyes as haze.

“There is emerging evidence over the past several years that particulates, when they are small enough, they make their way through the lungs to the blood vessels,” Al-Aly said. “They go to the liver, they go to the pancreas, they go to the kidneys. These particles are noxious. They irritate tissue and they damage tissue, they create oxidative stress, they create inflammation.”

Type 2 diabetes is associated with obesity and aging and occurs when the pancreas can’t make or process enough of the hormone insulin.

To look for a link between air pollution and type 2 diabetes, researchers analyzed data on 1.7 million U.S. veterans without diabetes, comparing PM 2.5 levels where they lived to their risk of being newly diagnosed with the disease during the next eight and a half years, on average. The researchers separated out the independent effect of air pollution by taking other diabetes risk factors, like obesity, into account.

Veterans’ annual average daily PM 2.5 exposure ranged from 5 to 22.1 micrograms per cubic meter (mcg/m3) of air. A 10-point increase in PM 2.5 concentration was associated with a 15 percent higher risk of developing diabetes, and an 8 percent higher risk of death. Risk of diabetes started to rise when pollution levels exceeded 2.4 mcg/m3, well below the EPA’s current standard of 12 mcg/m3 and the World Health Organization guideline of 10 mcg/m3.

Al-Aly and his colleagues then looked at worldwide PM 2.5 levels to estimate the total burden of diabetes due to air pollution. About 3.2 million new cases of diabetes, 8.2 million years of life lost to disability and more than 200,000 deaths annually were attributable to breathing dirty air, the authors calculated. Low-income and low-to-middle income countries bore the largest burden of air pollution-related diabetes.

While air in the U.S. is relatively clean compared to smog-choked parts of China, India and elsewhere, Al-Aly said, “we need to do better.”

He called for moving to “energy sources that contribute much less to pollution, more electric cars, more hybrid cars, more solar power and wind sources of energy rather than coal. It’s already happening, but probably not fast enough.”

In an editorial, Dr. Gary O’Donovan of the Universidad de los Andes in Bogota, Colombia, and Dr. Carlos Cadena-Gaitan of the Universidad EAFIT in Medellin, call the findings “another call for action.” They note that the current study did not adjust for physical activity, and that it’s possible to cut air pollution while promoting exercise with programs like Bogota’s Cyclovia, in which city roads are closed to motor vehicles on Sundays and holidays to make room for walkers and cyclists.

“More research is required to determine the independent associations of physical activity and air pollution with diabetes and other non-communicable diseases; nonetheless, there is more than enough evidence to justify the implementation of policies and interventions that might actually increase physical activity and decrease air pollution, such as Cyclovias, free sport and exercise facilities, bicycle sharing schemes, electric vehicles, low sulfur fuels, exhaust filters, and driving prohibition schemes,” they write.

Source: Reuters


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