The sentence fell in November 2014. "He is autistic, that's for sure, and we do not know how he will evolve," says the doctor. The lives of Camille and her companion have since been turned upside down: the autism of their son, now 11 years old, lives every hour of their daily lives.

Characterized by a set of behavioral, communication and social interaction disorders, autism spectrum disorder is experienced, in its heavy form, as a disability. A disability that has become a health concern.

According to the most recent assessments of industrialized countries, the prevalence rate of autism is estimated at 2%. In France, 8,000 autistic children are born each year, according to the National Institute of Health and Medical Research (Inserm).

On both sides of the Atlantic, the observation is unanimous: not only does the number of births of autistic children continue to increase, but its increase is exponential. In the United States, U.S. health authorities counted one in 5,000 autistic children in 1975, up from one in 68 in 2014. Only three years later, that rate had risen to one in 59.

Some qualify these figures by invoking the classic trompe l'oeil of any epidemiological data: the development of diagnosis. Do our societies really have more autistic people or simply more children diagnosed as such by medicine?

Pollution, suspect number one

For Camille, herself a medical engineer, the rise of screening cannot explain the exponentiality of the curve, this "increase in increase". The increase in cases of autism and other neurodevelopmental disorders is certainly linked in part to improved diagnosis, concedes Amaria Baghdadli, a psychiatrist. But "only partially", insists the doctor, head of the University Department of Child Psychiatry and the Resource Center on Autism at the University Hospital of Montpellier.

Discovered in the 1970s, the hereditary origins of neurodevelopmental disorders are attested by the entire scientific community. But DNA does nothing to explain this increase in the number of cases. And this, because of a clear scientific reality: our genetic heritage cannot evolve in such a short time.

Our environment, on the other hand, has experienced massive disruption since the post-war period. Air pollution, contamination of our plates by pesticides and synthetic fertilizers, foods processed by industry, endocrine disruptors: we now live in a chemically modified world.

Understand

Over the past decade, data collections have drawn an increasingly obvious parallel between pollution and autism. So there is a statistical occurrence, "but we have not yet established the causal link from a neurobiological point of view," says Dr. Baghdadli.

In retrospect, this previous research generally aimed to establish the link once the autistic diagnosis was established. This amounted to "making the path upside down," explains the psychiatrist. "You have to be there when exposures to pollutants occur, as early as pregnancy, not after."

This is where lies the novelty of the titanic research program that she coordinates with the University Hospital of Montpellier, known as the "Marianne cohort". This year, and over the next ten years, this study will medically follow 1,700 pregnant women and their families. Its goal: to understand the early biological and environmental determinants of autism and other neurodevelopmental disorders. Prevent, but also better support children already suffering from developmental disorders and autism spectrum.

The planet, society, the individual: one health

Funded by the National Research Agency, this giant study is the culmination of a long fight, led by Amaria Baghdadli in 2014. "We have come from so far away," sighs the psychiatrist. At the time when she was in medical school, her generation "did not even consider studying the link between health and the environment," recalls the fifty-year-old.

Even in 2017, his warnings had received a cautious welcome within the French scientific microcosm. But with the Marianne project this year, Amaria Baghdadli sees a civic and political awareness, which goes beyond the framework of autism: "Society and decision-makers finally grasp that human health depends on the environment, in the chemical and social sense". The planet, society, the individual: "There is only one health" summarizes the doctor.

This is one of the lessons Camille learns from her son's autism. Alternative medicine, lifestyle, organic food: the young woman, and her companion, biochemist, have gone green. For her child, it's too late, she sighs. But the cohort, Marianne fills her with hope "for others". "The more we demonstrate the environmental impact on our health, the more the lines will move," she hopes.

Paradigm shift

Globally, the progression of chemical pollution has not even begun to slow down. According to a study published in the medical journal "Environmental Science & Technology", the degree of chemical pollution of our planet crossed, in 2022, a new critical milestone.

>> Read also: Eternal pollutants: everywhere and forever

Demonstrating a direct correlation between health and environmental degradation could, however, trigger an ecological trigger. This is the purpose of Xavier Briffault, researcher in social sciences and health philosophy at the CNRS. We are witnessing, according to him, a political-environmental paradigm shift, from an ethical ecology to a public health ecology. In other words: from "polluting is bad" to "polluting hurts".

Health is not only an end of the ecological fight, but a means, continues the researcher: mobilizing our fears, the health issue makes it possible to put pressure on politicians according to this argument: "Not only are you killing the planet but you are killing us". The sociologist concludes with a glimmer of hope: "Health is one of the most powerful lever of action".

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