They wonder about the links between pesticides and autism

News 13 March, 2018
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    Mary Letendre, a family doctor in the Montérégie region, is convinced that pesticides are harmful to the health of his son David, who is autistic.

    Anne Caroline Desplanques

    Tuesday, 13 march 2018, 01:00

    Tuesday, 13 march 2018, 01:00

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    Scientists and parents are asking if the increase in the number of autistic children in Quebec in the past 15 years would be related to the exposure of more and more pesticides.

    “The pesticides, it is like the death Star in” star wars, breath Marie Letendre, a family doctor in the Montérégie region.

    David, the son of Dr. Letendre, is 14 years old, but he never came home to walk alone to school. There has never been a campfire or bike. All of this scares him. David is autistic.

    Like him, 16 940 children 1 to 17 years had a disorder in the autism spectrum (ASD) in Quebec in 2014-2015, three times more than it was 15 years ago, according to data from the national Institute of public health (INSPQ).

    “Every time I see a child five years of age, walks on a bicycle with his friends, I have a pinch. I say to myself : “Why my son can’t do that ?” “says Ms. Letendre.

    For this doctor, after more than 10 years of readings and conferences, the answer is clear : David has a genetic makeup that makes it more sensitive to the adverse effects of pesticides are ubiquitous in the region where he lives. The region is covered to 86 % of agricultural land.

    1500 cases

    This region is where one finds the greatest number of children with ASD in Quebec, according to the INSPQ.

    There are 1500 cases, almost 9 % of all children with autism in the province. Alone, Dr. Letendre follows five cases in his own practice in Châteauguay.

    The phenomenon worried her so much that a congress of medicine, held in Montreal at the end of the month of October, dedicated a conference to the adverse effects of pesticides on health.

    For the speaker, Louise Hénault-Éthier, director of scientific projects at the David Suzuki Foundation, the link between autism and pesticides has nothing to do with the hypothetical.

    It is particularly concerned with the effects of the pyrethroids and organophosphates.

    Used in the production of fruit and vegetables, these products are also used as repellents against fleas on pets.

    They are so common that they are found in bodies of water.

    “These insecticides are said to be neurotoxic because they interfere with the propagation of neural signals,” explains Ms. Hénault-Éthier.

    However, the smallest interference during the development of the brain of neurotoxic substances, for example, “can have great consequences,” says Maryse Bouchard, a professor in environmental health at the University of Montreal.

    Nerve Agents

    “As the very architecture of the nervous system is impaired, the consequences can be permanent “, she explains in a report provided to the organization Autisme Montréal.

    Ms. Bouchard has shown that the absorption of pesticides by a pregnant woman runs the risk of diminishing the iq of the fetus she is carrying.

    There is no scientific consensus

    The link between autism and pesticide is far from making unanimity in the scientific community.

    “There may be environmental factors involved, but there is no solid proof,” says Dr. Eric Fombonne, the child psychiatrist and epidemiologist of international repute.

    Specialist of autism, his research has in particular forced the prestigious journal of medicine The Lancet to deny an article that was published linking autism to the MMR vaccine (measles, mumps, rubella).

    Calling for caution, Éric Fombonne points out that ” the history of autism is made of false theories and treatments that don’t work “.

    Best detected

    According to him, until proof to the contrary, ” it is largely a problem of detection and definition, which explains the increased prevalence of autism “.

    Better diagnosed than before, as it’s better known, the disease has also extended its borders.

    “Children who, 15 years ago, were considered as having a language disorder are now diagnosed with a disorder on the autism spectrum “, he explains.

    The psychiatrist Alain Lesage, who conducted the latest census on autism from the national Institute of public health of Quebec, abounds in the same direction. He adds that the disparity in the number of cases according to the regions reflects an inequality in the provision of services, as the census only takes into account the children with autism who receive health services.


    Dr. Fombonne insists : the only certain cause of autism is genetic. When she explained that 2 to 5 % of cases 15 years ago, the genetics allows us to understand 25% to 30% today.

    It is expected that the progression of knowledge in genetics raises sooner or later the veil on the 70 % of cases still unexplained.

    “If I had eggs to put in a basket, it is in one of the genetics that I would place and not in that of the environment “, says the former director of the department of psychiatry of the Montreal children’s Hospital. Éric Fombonne today lies in Oregon, on the west coast of the United States.