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Autism Study of The Month: Recurrence Risk for Autism Spectrum Disorders: A Baby Siblings Research Consortium Study

By on August 15, 2011 in Autism Study of the Month

the_warner_siblings

Recurrence Risk for Autism Spectrum Disorders: A Baby Siblings Research Consortium Study

Source: http://psy2.ucsd.edu/~kdobkins/O,2011.pdf

Abstract

Objective: The recurrence risk of autism spectrum disorders (ASD) is estimated between 3 and 10%, but previous research was limited by small sample sizes and biases related to ascertainment, reporting, and stoppage factors. This study used prospective methods to obtain an updated estimate of sibling recurrence risk for ASD.
Methods: A prospective longitudinal study of infants at risk for ASD was conducted by a multi-site international network, the Baby Siblings Research Consortium. Infants (n=664) with an older biological sibling with ASD were followed from early in life to 36 months, when they were classified as ASD or Non-ASD. An ASD classification required surpassing the cutoff of the Autism Diagnostic Observation Schedule and receiving a clinical diagnosis from an expert clinician.
Results: 18.7% of infants developed an ASD. Infant sex and the presence of more than one older affected sibling were significant predictors of ASD outcome, with an almost three-fold increase in risk for males and an additional two-fold increase in risk if there was more than one older affected sibling. In contrast, the age of the infant at study enrollment, the sex and functioning level of the infant’s older sibling, and other demographic factors did not predict ASD outcome.
Conclusions: The sibling recurrence rate of ASD is higher than suggested by previous estimates. The size of the current sample and the prospective nature of the data collection minimized many limitations of previous studies of sibling recurrence, including
ascertainment bias, stoppage, and over-reporting. Clinical implications, including genetic counseling, are discusse

Press Release from Source

You can read here: http://www.ucdmc.ucdavis.edu/newsroom/newsdetail.html?key=5594&svr=http://www.ucdmc.ucdavis.edu&table=published

Translation

Researchers studied 664 participants in the US and Canada, finding that 132 infants met the criteria for an Autism Spectrum Disorder.

54 children received a diagnosis of “Autistic Disorder”.

78 children received a diagnosis of PDD-NOS.

80% of all children with an Autism Spectrum Disorder were male.

The over all rate of Autsm was 18.7%.

The rate in which there was one older sibling with Autism was 20.1%.

The rate in which there was more than one older sibling with Autism was 32.2%.

In My Opinion

This is simply my opinion of the story, stop reading if you do not want opinions and are happy just having read the details of the original study itself.

This study does not assume any “causes” which means that, even though many people will pull a genetic association out of this, it could still imply a common environmental element to the siblings.

While a much larger study than previous studies, it is still a fraction of all families and even still, the numbers are averages. Which means that the risks will be higher than 18.7% for some families but also less than 18.7% for some families.

As I always say… there is always a risk, no matter what you do or what you know. There’s never a 0% chance.

These are studies on the risk of Autism, there are other risks such as being still born, born with cancer and so on and so forth. To add up all of the risks of all the possibilities could lead to insanity. If no one ever had a child due to risks, there would be no children.

 

“Autism Study of the Month”
The purpose of the Autism Study of the Month series is to provide unpolluted (by the media) information about the studies released at least once a month in the study of possible Autism causes or risks.
You will find links to the actual studies, get to read the “abstract” of the study and, when possible, get the PR release from the source.
When it comes to science, let’s leave the media out of it.

Comments { 3 }

Autism Study of the Month: Ancestors that had mercury poisoning increases risk of Autism

By on August 9, 2011 in Autism Study of the Month

Mercury

Ancestry of Pink Disease (Infantile Acrodynia) Identified as a Risk Factor for Autism Spectrum Disorders

Source – http://www.tandfonline.com/doi/abs/10.1080/15287394.2011.590097?journalCode=uteh20

Abstract

Pink disease (infantile acrodynia) was especially prevalent in the first half of the 20th century. Primarily attributed to exposure to mercury (Hg) commonly found in teething powders, the condition was developed by approximately 1 in 500 exposed children. The differential risk factor was identified as an idiosyncratic sensitivity to Hg. Autism spectrum disorders (ASD) have also been postulated to be produced by Hg. Analogous to the pink disease experience, Hg exposure is widespread yet only a fraction of exposed children develop an ASD, suggesting sensitivity to Hg may also be present in children with an ASD. The objective of this study was to test the hypothesis that individuals with a known hypersensitivity to Hg (pink disease survivors) may be more likely to have descendants with an ASD. Five hundred and twenty-two participants who had previously been diagnosed with pink disease completed a survey on the health outcomes of their descendants. The prevalence rates of ASD and a variety of other clinical conditions diagnosed in childhood (attention deficit hyperactivity disorder, epilepsy, Fragile X syndrome, and Down syndrome) were compared to well-established general population prevalence rates. The results showed the prevalence rate of ASD among the grandchildren of pink disease survivors (1 in 25) to be significantly higher than the comparable general population prevalence rate (1 in 160). The results support the hypothesis that Hg sensitivity may be a heritable/genetic risk factor for ASD.

PR Release from Source

You can read here: http://www.swinburne.edu.au/chancellery/mediacentre/media-centre/news/2011/08/australian-research-finds-autism-risk-

Translation

Essentially what they are saying is that they found 522 people that were diagnosed with “Pink Desease” or mercury poisoning a long time ago and then checked out their grandchildren.

What they found was that 1 in 25 of those children were on the Autism Spectrum… which is a mighty big leap from the 1 in 160 children currently estimated in Australia.

The idea is that those 522 people must have had a greater weakness to mercury to be poisoned by it when other children were not… which, genetically, could mean that their children and even grandchildren would also have a greater weakness to it.

Thus, being exposed to it in seafood, dental fillings or preservatives in some vaccines may trigger a response in those children, including Autism.

My Opinion

This is simply my opinion of the story, stop reading if you do not want opinions and are happy just having read the details of the original study itself.

1. Aside from mercury poisoning symptoms having nothing in common with Autism symptoms, one would have to wonder how many, if any, of those 522 grandparents are Autistic.

2. The study makes no mention of verifying any of the original 522 people’s claims of having mercury poisoning. Being so long ago, it’s entirely possible they were misdiagnosed or not diagnosed at all. There was also no mention of verifying the grandchild’s Autism diagnoses either.

3. The rates, while still higher, resemble the rates found in the Korea total population study. A comparison of a control group vs comparing numbers of children being diagnosed on a regular basis is likely to be radically different for multiple reasons, including parents not recognizing the signs in their children, inappropriate facilities/services and so on.

4. If true, this would indicate that Autism is still largely genetic and is triggered by a toxin, such as mercury. Meaning that Autism could simply be onset since birth or “awoken” by introduction of some outside toxin, such as mercury.

I’ve long held the belief that Autism is not a “one cause, one cure, one story” disorder… that the reason it eludes scientists so much is that there is no one answer.

Do I believe that this study is the answer to it all? No. But it could lead to further answers. It certainly has a better chance than some other recent stories, like this one.

I have my doubts about this one as a lot of wholes were left open in terms of verifying data, it’s collection methods and what the numbers really mean.

But that doesn’t mean that there isn’t some real validity to it’s findings.

As I find more information, more insights, I’ll continue to update this article.

 

“Autism Study of the Month”
The purpose of the Autism Study of the Month series is to provide unpolluted (by the media) information about the studies released at least once a month in the study of possible Autism causes or risks.
You will find links to the actual studies, get to read the “abstract” of the study and, when possible, get the PR release from the source.
When it comes to science, let’s leave the media out of it.

Comments { 2 }