Are Environmental Factors a Significant Cause of Autism?

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Autism is a condition that has been associated with environmental factors in recent years. While many people understand this connection, other questions remain about the nature of autism and its causes. Experts say there are two camps: those who believe genetics play a significant role and those who think it can be explained by environmental factors such as vaccines or pollutants.

There are many environmental factors that may be influencing the risk of autism. These include pesticides, air pollution, and prenatal exposure to alcohol and tobacco. Read more in detail here: environmental factors influencing the risk of autism.


Environmental variables may have a role in the development of autism. There is still a lot of research going on in this field, and there isn’t a lot of agreement.

Autism is yet to be identified. Although many other variables, including as environmental exposure, have been demonstrated in studies to contribute to autism spectrum disorder, researchers think that there is a strong genetic component to the illness.

What Do You Mean When You Say “Environmental Factors”?

According to STAT News, the phrase “environmental variables” is often misused in autism diagnosis and treatment.

In a figurative sense, environment may relate to natural environments and their pollution by contaminants, which is a contributing factor in the development of autism spectrum disorder (ASD). Environmental factors, on the other hand, are defined by scientists and clinicians as anything that causes a biological or behavioral reaction that cannot be traced only to genetic factors (that is, it is not already present in a person’s DNA).

In this sense, environmental influences may refer to anything that triggers a biological or behavioral reaction, including food and drink, air quality, and anything that comes into touch with the skin. 

Epidemiology’s Terminology

The phrases danger and causation, likewise, are commonly misconstrued. A cause is a factor that contributes to the onset of a disease or condition. Risk factors, on the other hand, are variables that interact to raise the likelihood of a disease or condition developing.

Researchers in epidemiology have established extremely detailed criteria for determining whether something is a cause, a risk factor, or neither. When it comes to environmental variables that cause autism, no one environmental factor has met the requirements. As a result, experts have come to the conclusion that environmental influences must operate in concert with genetic elements to for autism to emerge. 

Environmental Factors & Autism

A number of environmental variables have been connected to a child’s risk of being diagnosed with autism. Among them are the following:

  • According to JAMA Pediatrics, having one autistic kid raises the likelihood of having a second child with the impairment, although the precise degree of risk is unknown.

  • Increased levels of air pollution during pregnancy (PLOS ONE) may be a risk factor when combined with genetic variables (Epidemiology).

  • Extreme sickness or infection during pregnancy, such as those induced by responses to bacterial or viral infections, may be an environmental factor in the development of autism, according to the journal Developmental Neurobiology. According to Frontiers in Human Neuroscience, vaccinations may help avoid some of these illnesses. 


According to the Annual Review of Public Health, exposing a kid to any of these (or other) environmental risk factors while still in the womb raises the likelihood of autism by up to four times the baseline incidence.

Environmental Factors & Genetics

Autism is caused by a complicated interplay between a variety of hereditary and environmental variables. More than a dozen genes have been linked to the development of autism spectrum disease, but the entire extent of environmental influences has yet to be determined.

Why is it so difficult to pinpoint the environmental elements that cause autism? One explanation is that all environmental studies are influenced by so-called confounding factors, which are characteristics that make it difficult to establish causal linkages between those factors and the development of autism.

According to certain studies (such as this one published in the BMJ journal), a woman who takes antidepressants during pregnancy may put her child at “greater risk” of having autistic spectrum condition. Other studies, such as this one published in Clinical Epidemiology, found “no significant connection between prenatal antidepressant drug exposure and autistic spectrum disorders in the children.”

In vitro exposure to valproate, which is used to treat epilepsy and bipolar disorder, has been linked to an increased risk of autism and other birth abnormalities, according to some study. As a result, several nations, such as France, have banned the prescription of specific types of valproate to pregnant or planning to become pregnant women.

As a consequence, studies looking into the involvement of environmental variables in the development of autism spectrum disease have found little evidence of cause and effect.

Environmental Factors Measuring Challenges

Furthermore, even the well-established links between environmental variables and autism remain a mystery. While children with older dads are more likely to acquire autism than children with younger fathers, it is unclear if the higher risk is due to the advanced paternal age.

Environmental influences are also difficult to monitor or assess. Parents may forget what they were exposed to, or they may be completely unaware of important aspects of their surroundings. On the other hand, parents may blame their child’s autism on an external issue that has nothing to do with autism.

Parental, Prenatal & Perinatal Factors

There are several well-known environmental risk factors for autism. The most well-known are those that are linked to pregnancy or birth.

Autism is linked to irregular bleeding during pregnancy and high blood pressure, according to the Autism magazine. Other concerns to consider include problems from a cesarean delivery or a premature birth. According to the Pediatrics journal, maternal hyperglycemia has also been linked to autistic symptoms.

The processes behind these linkages are still unknown, despite the fact that these aspects are well-documented.

Researchers studied the immunological systems of expecting moms to see whether they were at risk for autism. The Journal of Autism and Developmental Disorders reports that serious illnesses and infections (particularly bacterial infections) have been linked to an elevated risk of autism in offspring. The Epidemiology journal says, “Several maternal autoimmune diseases have been linked to autism.”

There is a lot of evidence that air pollution exposure during pregnancy, the third trimester, or early in a child’s life increases their chance of developing autism. However, there are other components to air pollution, and it is unclear which of these components has a role in the development of autism.

Several potential risk factors have been ruled out. While there are links between maternal immunological disorders and autism, routine vaccines for influenza and whooping cough given during pregnancy do not raise the risk of autism.

Vaccines & Smoking as Factors

Vaccinations given to children do not cause autism. The study that purported to reveal a causal relationship between the two was eventually withdrawn because it was false. Despite many assertions on social media and from questionable sources to the contrary, there is no reputable evidence that suggests a link.

It was formerly assumed that smoking during pregnancy increased the chance of autism. While smoking is usually hazardous (and may cause other birth abnormalities such as delayed development), the Pediatric and Perinatal Epidemiology journal reports that “no relationships were detected for childhood autism and Asperger’s syndrome” when it comes to smoking during pregnancy.

What should parents, prospective parents, and caregivers do in the face of environmental conditions that may cause autism? When a high risk of autism has been identified, parents should seek advice from a doctor, a pediatrician, or even a genetic counselor.

In most circumstances, following general health advice and receiving immunizations (for the mother) will assist to reduce the risk.

Controversy Over Vaccines

Is it possible that immunizations are one of the environmental causes of autism? The answer is a resounding no, yet the debate persists despite overwhelming evidence.

The legend dates back to 1998, when Andrew Wakefield, a British gastroenterologist, evaluated 12 youngsters, some of whom had autism spectrum disorders and others who did not. The measles virus and autism may be linked, according to a paper based on his research (published in The Lancet).

According to the findings, the measles-mumps-rubella (MMR) vaccination caused everything from tissue damage to immune system weakness. Wakefield and his colleagues observed that “many youngsters seem to acquire autism” after taking the vaccination.

Gastrointestinal issues are common in children with autism. The MMR vaccination, according to Wakefield, discharged toxins from the intestines into the circulation, which subsequently traveled to the brain.

Despite the fact that the research made no mention of a causal link between vaccination and autism, Wakefield made public remarks calling for the vaccine to be halted. These words exacerbated the vaccination frenzy, which Wakefield referred to as a “moral problem.”

Wakefield made his statements on American television in 2000, stating that vaccines were to blame for what he termed a “autism pandemic.” This re-ignited what had previously been a fringe anti-vaccine movement in the United States, bringing it into the mainstream.

Fatal Flaws & Conflicts of Interest

Wakefield had a conflict of interest while he worked on his research for The Lancet, getting almost £400,000 that he had not reported, according to British journalists in 2004. Wakefield was charged with dishonesty and professional misconduct by the UK General Medical Council.

The editor of The Lancet issued a statement the day before the revelation surfaced, calling Wakefield’s study “fatally defective” and claiming that if the conflict of interest had been revealed, the paper would have been rejected.

Ten of the paper’s 12 co-authors removed their names from publication. They explained their retraction by saying that although the report did not prove a causal relationship between the vaccination and autism (due to inadequate data), the “huge consequences for public health” were enough for them to repudiate The Lancet’s initial interpretation of the study’s findings.

Wakefield had registered for a patent for a “single-jab measles vaccine” before his campaign against the MMR vaccination, according to further study. In addition, contrary to what he said in the Lancet, the MMR vaccination “results in […] widespread developmental problem including autism in certain newborns,” according to the first page of Wakefield’s patent application.

Wakefield denied any misconduct and argued that the medical and scientific institutions had treated him unfairly. The General Medical Council judged him guilty of all accusations of professional misconduct in 2010, accusing him of behaving with “callous disregard” for the children in his research and of “putting the medical profession into disgrace.”

He was struck off the United Kingdom’s medical register, the worst sanction the council could inflict. Wakefield’s eligibility to lawfully practice medicine in the United States was terminated as a result of the decision. Wakefield’s initial paper was formally retracted by The Lancet in the same year.

‘This Harmful Vaccine Fear’

The BMJ magazine released an article in 2011 pointing out many contradictions in Wakefield’s Lancet paper, including the fact that the parents of the 12 children in the research were recruited by anti-MMR vaccination activists. Wakefield, according to the editors of the BMJ, was “a fraud,” not inept or wrong.

“Clar proof of data fabrication should finally seal the door on this detrimental vaccination fear,” they stated.

The notion that there is a relationship between autism and vaccinations, on the other hand, continues. In three test cases in 2009, the United States Court of Federal Claims concluded that “vaccines do not cause autism,” particularly dismissing any relationship between the MMR vaccine and autism spectrum disorder. “These verdicts have done nothing to soothe the passionate discussion,” Discover Magazine wrote over a decade ago.

Celebrities and politicians, as well as conspiracy theorists and bad faith actors, continue to disseminate the idea on social media. Doctors and researchers have repeatedly rejected the vaccination, yet despite — or maybe because of — this, a movement of vaccine skeptics has emerged. Measles outbreaks have been reported in the United States, Australia, and Europe, mostly due to vaccine phobia and parents refusing to vaccinate their children.

A number of European countries have made child vaccines obligatory and levied penalties on parents who do not vaccinate their children as a result of the issue.

Vaccination skepticism (also known as vaccine hesitancy) was named one of the greatest dangers to world health by the World Health Organization in 2019.

The Price of Vaccine Doubt

According to Discover, the emotional toll that autism can have on a family has prompted well-intentioned individuals to hunt for reasons or cures. Even as the number of autism diagnoses rises, the causes and processes of the disorder remain unknown. Autism spectrum disorders are “complex, lifelong, neurodevelopmental illnesses of mainly unknown origin,” according to the Annual Review of Public Health.

With this in mind, Discover says that, despite the medical backing for vaccinations, it’s not unexpected that desperate parents and caregivers could grasp onto Andrew Wakefied’s debunked claims.

The consequences of this may be fatal. A 4-year-old kid died of the flu in Colorado in February 2020, after his mother was encouraged by an anti-vax Facebook community (with over 178,000 members) to feed her son vitamins, botanicals, fruits, and veggies instead of the prescribed Tamiflu from the child’s doctor. One of the group members advised the mother to “cook thyme on the stove” as the boy’s health deteriorated. 

Following the boy’s death, the discussion was deleted from the Facebook group. The facility, according to the group’s owner, “[never] offered any meaningful therapies.”

Andrew Wakefield continues to argue against vaccinations to this day, claiming that his research and findings are correct.

Research is ongoing.

While it is obvious that immunizations do not cause autism, other environmental variables, such as exposure to chemicals, may play a role in the disorder’s genesis.

This is a very important topic of autism research. Environmental risk factors for autism are still being researched, as well as how they relate to genetic risk.

We shall hopefully learn more about the role of environmental variables in autism in the future years. This study might then be used to enhance efforts in prevention, intervention, and therapy.


The “identify aspects of the environment that affect communication with an individual with autism” is a question that has been debated for many years. Some believe that environmental factors are not a significant cause of autism, while others believe it to be true.

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