Wednesday, February 18, 2015

Correlation between Autism and GMOs

The increase in the number of autism cases has been correlated to genetically modified organisms (GMOs) and vaccines for long. While it is true autism cases has been in the rise in the past few decades, the spurious correlation to vaccines and GMOs does not hold any water or stand the security of science.

Arvind Suresh in an article written for Genetic Literacy Project says that researchers now believe that nothing is causing the rise of this disorder. It is merely a statistical mirage. Compared to about one out of every 2000 children who had autism in 1970s and 80s, the figure has skyrocketed to one in 150 among 8-year-olds in the USA, according to the Centre for Disease Control and Prevention.

For the critics of GMOs and vaccination, it is a mighty easy task to speculate and do some armchair research – correlate the increase in vaccination and increase in the adoption of GM crops to the increase in autism cases over the years and drive home the point that autism is caused by GMOs and vaccination. Bear in mind the advocate for anti-vaccination, Jenny McCarthy proudly said in an Oprah interview, “The University of Google is where I got my degree from”.

If you want to have fun with statistics where one can correlate anything with similar trends and jump into a conclusion, visit this page: . Here you will see real spurious statistics – among others, age of Miss America correlates with murder by steam, hot vapours and hot objects, US crude oil imports from Norway correlates with drivers killed in collision with railway train, and number of people drowned by falling into a swimming pool (USA) correlates to number of films Nicolas cage appeared in.

If one were to do the same standard to research done by critics of GMOs and the pseudoscience, then increase in autism could also be correlated to increase in organic food sales – see figure below.

So why the increase? In fact evidence show that there is no dramatic increase in autism after all. 
The apparent increase is due to changes in the diagnostic criteria, increased screening and awareness of this disorder. Forbes reported that:
The way autism is defined in the U.S. has changed dramatically since 1980, when it first appeared in the DSM-III (Diagnostic and Statistical Manual of Mental Disorders) as “Infantile Autism” and could only be diagnosed in children whose symptoms began before they were three years old. Autism spectrum disorders have expanded to include diagnosis without a specific age requirement beyond the “early developmental period” and without requiring significant language impairment in the recently revised DSM-5.
The vast majority of people diagnosed with autism spectrum disorders today would never have qualified under the 1980 classification, and no formal classification separate from schizophrenia existed before then. So it’s not surprising that numbers have increased in the U.S.

The definition of ASD has also been expanded to include a collection of brain development disorders such as Asperger’s syndrome. For example, Denmark expanded its diagnostic criteria in 1994.

Not only the diagnostic criteria was widened, the national data tracking in Denmark began to include diagnosis made from outpatient patient visits rather than just diagnosis of those admitted to a healthcare facility. This happened in every country where autism cases were soaring.

A paper published in JAMA Pediatrics (2015 Jan 1;169(1):56-62) concludes that the change in diagnostic criteria taken together along with the diagnoses made outside of a healthcare facility accounted for as much as 60 per cent of the increase in prevalence of autism spectrum disorders.
It is important to understand that with early screening programmes introduced by governments and newer diagnostic techniques coming into play, there will be a prevalence of certain diseases. The same case can also be argued for increase in certain types of cancers.

Whatever, it is cherry picking of data should be stopped and the public must be equipped with some knowledge to discriminate against pseudoscience. 

By Dr Mahaletchumy Arujanan

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