(TMU) — Scientists are increasingly reaching a consensus that exposure to air pollution increases the risk of depression and suicide, according to the first review of studies on the subject.
While the harmful effects of breathing filthy air have long been known, a growing body of research has found that the psychological effects of pollution may also be profound.
The review suggests that by cutting air pollution around the world, millions of people could be saved from falling into the throes of depression. However, scientists remain uncertain that they can prove that exposure to toxic air is the definitive cause to depression.
The toxic particles emitted by cars and industrial source are believed to cause inflammation in the brain as they seep into the bloodstream following inhalation, or even potentially through impacts on the production of stress hormones.
In a press release, lead author Dr. Isobel Braithwaite of University College London (UCL) said:
“We already know that air pollution is bad for people’s health, with numerous physical health risks ranging from heart and lung disease to stroke and a higher risk of dementia.
Here, we’re showing that air pollution could be causing substantial harm to our mental health as well, making the case for cleaning up the air we breathe even more urgent.”
Depression and suicide risk linked to air pollution | UCL News – UCL – London's Global University https://t.co/3Gxeui6Lwx
— Plume Plotter (@plumeplotter) December 18, 2019
The review, published Wednesday in Environmental Health Perspectives, looked at studies from 16 countries that investigated the long-term impact of breathing in toxic airborne particles. Researchers found 25 studies meeting their criteria and used them to look at the correlation between long-term exposure to particulate matter and depression, suicide, anxiety, bipolar disorder, and psychosis.
The strongest associations were found between exposure and depression and suicide. However, only limited links were found with anxiety and none with bipolar disorder and psychosis.
Researchers remain unsure about whether air pollution is the actual cause of mental health problems or is simply associated with them, but evidence does exist that there is a physical connection.
In the press release, Braithwaite said:
“We know that the finest particulates from dirty air can reach the brain via both the bloodstream and the nose, and air pollution has been implicated in increased neuroinflammation, damage to nerve cells and to changes in stress hormone production, which have been linked to poor mental health.”
The study found that people who spend six months in an area with double the World Health Organization‘s (WHO) fine particulate matter (PM2.5) limit of 10 micrograms per cubic metre of air (μg/m3) face a 10 percent greater likelihood of falling into depression versus those living in areas that meet the limit.
Global city PM2.5 levels can range from the extremely hazardous 114 μg/m3 in Delhi, India, to only 6 μg/m3 in Ottawa, Canada.
NEW REVIEW: Air Pollution (Particulate Matter) Exposure and Associations with Depression, Anxiety, Bipolar, Psychosis, and Suicide Risk: A Systematic Review and Meta-Analysis. Read the article ➡️ https://t.co/cwUFKjiJkS @NHS_HealthEdEng @ucl
— Environmental Health Perspectives (@EHPonline) December 18, 2019
A reduction of air pollution to the European Union’s legal of 25 legal limit of 25 μg/m3 could lead to a major drop in global depression levels, Braithwaite said. She told the Guardian:
“You could prevent about 15% of depression, assuming there is a causal relationship. It would be a very large impact, because depression is a very common disease and is increasing.”
However, even incremental increases in risk can be harmful to the global population—especially because less than 1 out of 10 people in the world lives within the WHO-recommended level of clean air. Braithwaite added:
“This is something everyone is exposed to, so at the population level it is potentially concerning.”
Dr. Ioannis Bakolis, a senior professor of Biostatistics and Epidemiology at King’s College London, was not a part of the research team, told the Guardian:
“This is a comprehensive review over a 40-year period. Although the studies included were from different parts of the world—eg China, the US, Germany—and varied in sample size, study design and measures of depression, the reported associations were very similar.”
Senior study author Dr. Joseph Hayes at UCL recommends a broader approach to tackling air pollution, which would benefit the mental health of populations even if it is found that air pollution isn’t the direct cause of depression or suicide. He said:
“Our findings correspond with other studies that have come out this year, with further evidence in young people and in other mental health conditions. While we cannot yet say that this relationship is causal, the evidence is highly suggestive that air pollution itself increases the risk of adverse mental health outcomes.
A lot of what we can do to reduce air pollution can also benefit our mental health in other ways, such as enabling people to cycle or walk rather than drive, and enhancing access to parks, so this adds support to the promotion of active travel and urban green spaces.”
Biden to Ban Menthol Cigarettes, Citing Health Impact on Youth and Black People
The Biden administration is reportedly planning to propose an immediate ban on menthol cigarettes, a product that has long been targeted by anti-smoking advocates and critics who claim that the tobacco industry has aggressively marketed to Black people in the U.S.
On Wednesday, the Washington Post reported that the administration could announce a ban on menthol and other flavored cigarettes as soon as this week.
Roughly 85 percent of Black smokers use such menthol brands as Newport and Kool, according to the Food and Drug Administration. Research has also found that menthol cigarettes are easier to become addicted to and harder to quit than unflavored tobacco products, along with other small cigars popular with young people and African Americans.
Civil rights advocates claim that the decision should be greeted by Black communities and people of color who have been marketed to by what they describe as the predatory tobacco industry.
Black smokers generally smoke far less than white smokers, but suffer a disproportionate amount of deaths due to tobacco-linked diseases like heart attack, stroke, and other causes.
Anti-smoking advocates like Matthew L. Myers, president of Campaign for Tobacco-Free Kids, also greeted the move to cut out products that appeal to children and young adults.
“Menthol cigarettes are the No. 1 cause of youth smoking in the United States,” he said. “Eliminating menthol cigarettes and flavored cigars used by so many kids will do more in the long run to reduce tobacco-related disease than any action the federal government has ever taken.”
However, groups including the American Civil Liberties Group (ACLU) has opposed the move, citing the likelihood that such an action could lead to criminal penalties arising from the enforcement of a ban hitting communities of color hardest.
In a letter to administration officials, the ACLU and other groups including the Drug Policy Alliance said that while the ban is “no doubt well-intentioned” it would also have “serious racial justice implications.”
“Such a ban will trigger criminal penalties, which will disproportionately impact people of color, as well as prioritize criminalization over public health and harm reduction,” the letter explained. “A ban will also lead to unconstitutional policing and other negative interactions with local law enforcement.”
Pollution Is Making Human Penises Shrink and Causing a Collapse of Fertility, Scientists Say
With many still scoffing at the idea of rampant pollution posing a threat to humanity, a new study could drastically change the conversation: the chemicals across our environment could be the cause of shrinking human penises.
According to a new book by Dr. Shanna H. Swan, conditions in the modern world are quickly altering the reproductive development of humans and posing a threat to our future as a species.
The argument is laid out in her new book Count Down: How Our Modern World Is Threatening Sperm Counts, Altering Male and Female Reproductive Development, and Imperiling the Future of the Human Race.
The book discusses how pollution is not only leading to skyrocketing erectile dysfunction rates and fertility decline, but also an expansion in the number of babies born with small penises.
While it may seem like good fodder for jokes, the research could portend a grim future for humanity’s ability to survive.
Swan co-authored a study in 2017 that found sperm counts had precipitously fallen in Western countries by 59 percent between 1973 and 2011. In her latest book, Swan blames chemicals for this crisis in the making.
“Chemicals in our environment and unhealthy lifestyle practices in our modern world are disrupting our hormonal balance, causing various degrees of reproductive havoc,” she wrote in the new book.
“In some parts of the world, the average twentysomething woman today is less fertile than her grandmother was at 35,” she also wrote, noting that men could have only half the sperm count of their grandfathers.
Swan blames the disruption on phthalates, the chemicals used in plastic manufacturing that also have an impact on how the crucial hormone endocrine is produced
However, experts note that the proper implementation of pollution reduction measures could help humanity prevent the collapse of human fertility.
Visualizing The World’s Deadliest Pandemics By Population Impact
Humanity has been battling against disease for centuries.
And while most contagious outbreaks have never reached full-blown pandemic status, Visual Capitalist’s Carmen Ang notes that there have been several times throughout history when a disease has caused mass devastation.
Here’s a look at the world’s deadliest pandemics to date, viewed from the lens of the impact they had on the global population at the time.
Editor’s note: The above graphic was created in response to a popular request from users after viewing our popular history of pandemics infographic initially released a year ago.
Death Toll, by Percent of Population
In the mid-1300s, a plague known as the Black Death claimed the lives of roughly 200 million people – more than 50% of the global population at that time.
Here’s how the death toll by population stacks up for other significant pandemics, including COVID-19 so far.
The specific cause of the Black Death is still up for debate. Many experts claim the 14th-century pandemic was caused by a bubonic plague, meaning there was no human-to-human transmission, while others argue it was possibly pneumonic.
Interestingly, the plague still exists today – however, it’s significantly less deadly, thanks to modern antibiotics.
History Repeats, But at Least We Keep Learning
While we clearly haven’t eradicated infection diseases from our lives entirely, we’ve at least come a long way in our understanding of what causes illness in the first place.
In ancient times, people believed gods and spirits caused diseases and widespread destruction. But by the 19th century, a scientist named Louis Pasteur (based on findings by Robert Koch) discovered germ theory – the idea that small organisms caused disease.
What will we discover next, and how will it impact our response to disease in the future?
Like this? Check out the full-length article The History of Pandemics
Republished from ZH with permission.