Three Recent Studies Have Linked Air Pollution to Autism

Three recent studies, in Asia, Canada and Europe, have shown that exposure to PM2.5 particle pollution and nitric oxide has led to an increased risk of autism.

Today, 55 percent of the world’s population lives in a city, and according to the UN, that figure is set to rise to 68 percent by 2050. In the US, according to the US Census Bureau, 79 percent of all Americans live in cities.

For young couples planning on having children, this can be a problem. Three recent studies have linked air pollution in big cities to an increased risk of autism spectrum disorder (ASD) in children.

RELATED: AIR POLLUTION CAN CAUSE BIRTH DEFECTS AND FETAL DEATH ACCORDING TO A NEW STUDY

Shanghai, China

A study released on November 5, 2018, by Monash University in Australia linked exposure to toxic air pollutants to an increased risk of developing autism.

Researchers studied children in Shanghai, China for nine years, from birth to three-years-of-age. They found that exposure to fine particles (PM2.5) increased the children's risk of developing autism spectrum disorder by a staggering 78%.

Particles are categorized by their size, with PM10 being the largest, then PM2.5, and PM1 being the smallest.

PM2.5 primarily comes from vehicle exhausts, industrial emissions, construction sites, and road dust. The smaller the particle, the more easily it can penetrate the lungs and enter the bloodstream.

Monash University Associate Professor Yuming Guo said, "The developing brains of young children are more vulnerable to toxic exposures in the environment and several studies have suggested this could impact brain function and the immune system."

PM2.5 pollution is a particular problem in countries such as China and India.

According to Professor Guo, PM1 pollution comprises 80 percent of PM2.5 pollution in China. "Despite the fact that smaller particles are more harmful, there is no global standard or policy for PM1 air pollution."

Denmark

A third study, published in 2018 in the journal Environmental Epidemiology, observed 15,000 Danish infants born between 1989 and 2013. It concluded that exposure to air pollution, both, before birth and during the first months of life, was associated with ASD. Again, the culprit was nitric oxide.

Vancouver, Canada

In a separate study published in January 2019 in the Journal of the American Medical Association Pediatrics, scientists studied 132,000 children born in Vancouver, Canada between 2004 and 2009. The births happened in Metro Vancouver, and the children were followed through 2014.

Diagnoses of ASD were made with the Autism Diagnostic Interview-Revised and Autism Diagnostic Observation Schedule.

Scientists looked at the mothers' exposure to PM2.5, nitric oxide (NO), and nitrogen dioxide (NO2), and they found a link between exposure during pregnancy to nitric oxide, which is produced in car exhausts, and a greater incidence of autism spectrum disorder. 

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Skyrocketing Rates of Autism in the US

The US Centers for Disease Control's Autism and Developmental Disabilities Monitoring (ADDM) Network reported that in 2014, 1 in 59 American children had been identified with an autism spectrum disorder (ASD). Numbers showed that 1 in 37 boys and 1 in 151 girls had the disorder.

Increasing rates of autism
Increasing rates of autism. Source: Fred the Oyster/Wikimedia Commons

Those numbers climbed dramatically between the years 2000 and 2014.

Year Number of Children
2000 1 in 150
2004 1 in 125
2006 1 in 110
2008 1 in 88
2010 1 in 68
2012 1 in 69
2014 1 in 59

The 2014 number reflects a 15% increase from 2010, an 86% increase from 2006, and a 154% increase from 2000.

The Economic Cost of Autism

In 2015, the cost of caring for Americans with autism reached $268 billion, and it is estimated that it will reach $461 billion by 2025.

Medical expenditures for children and adolescents having ASD were 4 to 6 times greater than for those without ASD. Families with an ASD child shelled out between $4,110 and $6,200 more in medical costs each year than families without a child having the condition.

Besides medical costs, intensive behavioral interventions can cost $40,000 to $60,000 per child per year. Passage of autism insurance legislation by 48 US states is providing access to medical treatment and therapies.

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Autism and Vaccines

In 1998, English physician Andrew Wakefield and 12 colleagues published a paper in the journal The Lancet that suggested a link between the measles, mumps, and rubella (MMR) vaccine and autism. The authors’ sample size was less than 12 children.

Other studies were immediately conducted that refuted those conclusions, and 10 of Wakefield’s co-authors retracted their paper. The Lancet reported that Wakefield’s study had been funded by lawyers representing parents who were suing the vaccine-producing companies.

By 2010, the Lancet had completely retracted Wakefield’s paper, and its authors were found to be guilty of deliberate fraud for picking and choosing only data that suited their conclusion.

The British Medical Journal attributed that fraud to a desire for financial gain and reported that the participants had planned a joint venture that would profit from the MMR vaccine scare.

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Wakefield has been struck off from the British medical register and is unable to practice medicine in the UK. All his articles have been retracted.

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