World Autism Views 2011: What does the world think about the causes of autism?

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What causes autism?

That is the question many researchers, professionals and parents are asking around the world? However, so far, there is no consensus from scientists. There are many theories and some mixed evidence but at this point no clear answer to this question. We wanted to know what people around the world believe causes autism.

The World Autism Views 2011 survey offered 10 statements about the causes of autism and asked respondents to tell us whether they believed each statement to be: Definitely False, Probably False, Probably True or Definitely True. There was also a option labeled, "Don't know enough to answer" for each statement.

There were some interesting, and statistically significant, differences in how different groups of people rated each statement.

"autism is inherited through genetics"




This was one of the statements about the causes of autism that respondents were asked to rate as True or False. A lot of research has looked at the role of genetics in autism. The majority of people thought that this statement was "Probably True".

In total 47% thought the statement was true and 33% thought it was false (the others didn't know enough to answer). This first bar chart shows how many people selected each answer.

The data show some interesting, and statistically significant, differences in how different regional groups responded to this statement.
People in Asia, Southern Europe and Latin America on average think it's false that autism is inherited

The chart, "Regional Average Scores" shows which regions were most likely to rate the statement "autism is inherited through genetics" as true (positive scores, above the line on the chart) or false (negative scores, below the line on the charts).

The differences between the three regions most likely to rate the statement as false (Asia, Southern Europe and Latin America) and the scores from North America are statistically significant.


"autism is caused by exposure to toxic substances"




More recently there has been some published research suggesting a link between environmental toxins and autism but how many people actually believe this to be the case?

In our sample 36% thought the statement "autism is caused by exposure to toxic substances" is true and 43% thought it to be false (the rest said they didn't know enough to answer).

This first bar chart shows you how many people selected each answer.

North American's more likely to agree that autism is caused by exposure to toxic substances, the rest of the world disagrees
The data show a very clear global split in opinions about the link between autism and environmental toxins. The second chart "Regional Average Scores" shows which regions were most likely to rate the statement "autism is caused by exposure to toxic substances" as True (positive scores) or False (negative scores).

North American's were most likely to agree with this statement as a group while every other regional group was more likely to think it false. In fact, 54% of all respondents living in North America rated this statements as either "Probably True" or "Definitely True" whereas only 26% of those living in Southern Europe thought the same.

"vaccinations can cause autism"

There has been much controversy in the Western media over the issue of vaccinations and autism since Dr. Wakefield's now infamous paper was published by the British medical journal The Lancet in 1998 (before being retracted in 2010). During the first peak of the controversy in the UK (1996 - 2006) a group of researchers tracked mothers' attitudes towards the MMR (measles, mumps and rubella) vaccination. These data, published in 2007, suggest an increase in mothers in the UK believing that the MMR vaccination is safe. A study published in Pediatrics in 2010 explored parental beliefs to vaccines with an online survey of 1,552 parents in the US. They found that about 1 in 4 US parents believed that some vaccines can cause autism in healthy children. This survey was performed before the retraction of original The Lancet paper. But we don't know how far this idea has spread around the world and if people outside the West think vaccines can cause autism.

Of the 2,274 people from all over the world who responded to this statement in the World Autism Views 2011 survey, 30% thought it was true (20% said "Probably True" and 7% said "Definitely True") that vaccinations can cause autism. The majority, 51% thought the idea that vaccinations can cause autism was false (the rest didn't know enough to answer).

Although the majority thought it false that vaccines cause autism when we start to look at each region separately we see that there are distinct response patterns across the globe. All regions, on average, rated the idea that vaccinations cause autism as "false" (scores below the line on the bar chart). However, two regions, Latin America and Eastern Europe were statistically more likely to rate the statement as false than North America. in fact, 23% of Latin American respondents rated the statement as true while almost twice as many North Americans, 41%, thought it true that vaccines cause autism.



It is of course useful to know what the general population thinks about the relationship between vaccinations and autism. However, it is parents who ultimately decided whether a child is vaccinated or not. So we broke down these data more specifically to look at how a person's relationship to autism impacted their response to this statement. We found a major difference in the the opinions of parents and grandparents of children with autism as compared to people with other relationships to autism. The bar chart shows that both parents and grandparents on average were significantly more likely to think that vaccines cause autism than Autism Professionals, people with autism and those describing themselves as having a "General" or "other" interest in autism.



When we look at parents only then we can see the regional differences in people's belief in the idea that vaccines cause autism. The majority of the parents living in Africa and the Middle East in Latin America and in North America selected "Probably True" to the statement that "vaccines can cause autism". Parents in Northern Europe were most likely to select "don't know enough to answer". Parents in Eastern Europe were most likely to select "Probably False". The average regional scores for parents of children with autism only are shown on the left.

Of 272 parents of children with autism living in Asia 31% thought it true that vaccines can cause autism. Similarly, of the 130 parents of children with autism living in Eastern Europe 31% thought it true that vaccines can cause autism.

A larger proportion of parents in the Western world believe that autism can be caused by vaccines, of the 148 parents we asked in Northern and Western Europe 44% thought it true and 51% of the 209 North American parents believed that vaccines can cause autism.


Next: What does the world think about autism treatment?
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