The air pollution breathed by thousands of people in Britain every day may be linked to an increased risk of developing autism, according to new research.
A review of the most recent scientific literature found that babies with a higher genetic risk for the developmental disorder who were exposed to four common air pollutants were more likely to develop the condition.
It is thought that when breathed during early childhood or in utero, these microscopic pollutants can reach the bloodstream.
There, they can bypass the brain’s protective layers, causing inflammation, changing the way nerves function and develop, increasing the risk of disorders.
It comes as autism rates have soared around the world in recent years. Analyzes show that diagnoses of the disorder have increased nearly 800 percent in Britain over the past few decades, and rates have nearly tripled in the United States.
Dr. Haitham Amal, head of the Department of Laboratory of Neuromatics, Cell Signaling and Translational Medicine at the Hebrew University of Jerusalem, who led the new study, said they were trying to understand what might be contributing to this increase.
His lab has focused primarily on nitric oxide (NO), a gas released when fossil fuel is burned in cars.
Dr. Amal said, “My lab has shown that NO plays an important role in ASD (autism spectrum disorder).”
This map shows the 10 areas with the highest levels of air pollution recorded in 2023. These areas had almost double or triple levels of particulate matter, which are microscopic particles of pollution that can penetrate deep into the human body, recommended by the World Health Fund. Organization
In the new study, published in the magazine Brain medicineDr. Amal looked four different components of air pollution: particulate matter, nitrogen oxides, sulfur dioxide and ozone.
Nitrogen oxides refer to both nitric oxide and nitrogen dioxide, two pollutants released when burning fossil fuels.
Particulate matter is a general term for microscopic dust, liquid, or smoke particles produced at construction sites, power plants, and automobiles.
It is between seven and 30 times smaller than the diameter of a human hair.
Sulfur dioxide is a colorless gas or liquid that is produced when fossil fuels are burned or when metal such as aluminum is melted.
Ozone is a colorless, odorless gas produced in chemical plants, paint shops and oil-based printing presses, and can also be generated when other pollutants combine with the atmosphere.
The authors did not provide a figure, but older Harvard research suggests that exposure to air pollution, such as particulate matter, may increase the risk of autism by up to 64 percent.
A review of the most recent scientific literature found that babies with a genetic predisposition to autism exposed to four common air pollutants were more likely to develop the condition.
Doctors aren’t sure what causes autism to develop, but about 15 percent of cases are linked to a specific genetic mutation.
Experts are also not sure why the risk of developing this condition might be related to air pollution, but they have theories.
First, when someone inhales one of these pollutants, it can cause inflammation in the nerves, which damages them over time and leads to dysfunction.
People are most vulnerable to these effects when they develop in utero and early childhood, because their brains are still forming, Dr. Amal said.
Studies have shown that these small polluting particles can even directly enter the brain of the fetus, he said.
Long-term changes in the way the brain works can cause some of the behavioral symptoms associated with autism, he added.
NO is just one of numerous substances released when burning fossil fuels, primarily through power generation and transportation.
Air pollution in general is measured by recording levels of particulate matter (PM2.5), the levels of microscopic particles in the air that can penetrate deep into our lungs and cause a variety of health problems.
Dr. Amal (center) and his team of researchers in their laboratory in Jerusalem. The team focuses on nitric oxide and its role in the brain.
According to data collected by the IQAir website, Surbiton, south-west London, recorded the worst average PM2.5 levels in the UK at 13 micrograms per cubic meter in 2023.
This is almost triple the World Health Organization guideline of 5 PM2.5 that people should be exposed to per year.
Other areas with high levels of PM2.5 in Britain included Willesborough, Faversham and Lower Stoke in Kent, Worcester Park in London and Worsley in Greater Mancester.
By contrast, Church Hill in West Sussex had the lowest level of PM2.5 in 2023, at just 3.8.
This was followed by West Hoathly, also in West Sussex, with 4:10 pm2.5 during the year, as well as Motherwell and Currie in Scotland, which recorded 4.1:00 pm2.5.
Data from 2023 shows that nine areas of Britain did not meet annual average nitrogen dioxide limits of 40 micrograms per cubic meter.
There was Greater London, the West Midlands, Greater Manchester, West Yorkshire, Liverpool, Nottingham, Bristol, Coventry/Bedworth and the South East.
Having autism means that a person’s brain works differently than normal.
It is not a disease and people suffer from it from the moment they are born, although it may not be detected until childhood and sometimes much later.
Autism exists on a spectrum. Some people will be able to lead a fully functional life without additional help. Others may need full-time assistance.
Classic signs of autism include problems communicating, finding certain stimuli or situations overwhelming, and repetitive behaviors.
According to a 2021 Newcastle University study, approximately one in 57 children in the UK is autistic.
However, rates have soared in recent years, leading to suggestions that the disorder is now being overdiagnosed.
Experts maintain, however, that autism has been grossly underdiagnosed in the past, especially among women and girls.
This has led to a backlog of patients diagnosed later in life.
An additional factor that could have contributed to the increase is the disappearance of Asperger’s syndrome, previously considered a separate disease, but now considered another form of autism that also increases the numbers.
