April 16, 2012

Correlation vs. Causation: Decoding Autism Research

imageBy Sally Raskoff

Recent news reports cite a huge increase in autism rates. Autism, a disorder involving problems with social interaction and communication, is estimated at 1 in 88 children. The rates by gender are 1 in 54 boys and 1 in 252 girls, so it’s much more prevalent in boys.

The Centers for Disease Control and Prevention (CDC) website has a great discussion of these numbers and speculation about increase.

A large part of the reason for this increase may be because autism is more often reported and diagnosed now than it was in the past. The CDC also mentions that older parents, premature births or parental drug use are risk factors. Scientific studies continue to investigate genetic factors and other biological factors.


Source: Centers for Disease Control and Prevention, 2012

Are these correlations really indicators of causation? Hopefully you’ve already learned that correlation does not equal causation. More studies need to be done to firmly establish a causal link between the variety of hypothesized factors and autism.

Is autism solely caused by the individual and biological factors that are most often discussed? Some interesting sociological research has been published that sheds light on these issues.

In 2011, sociologists Marissa D. King and Peter S. Bearman published an article called “Socioeconomic Status and the Increased Prevalence of Autism in California,” where they investigate both individual level and community level factors and their impact upon autism diagnoses. They replicated the results of other studies yet found some fascinating dynamics when it comes to autism diagnosis patterns over time.

Significant individual level factors that were linked to autism diagnoses included: not being on Medi-Cal (California’s version of Medicaid); being first born, premature, or male; having an older biological parent, and having more highly educated parents.

The socioeconomic status (SES) aspects are telling: those with higher SES are more likely to be diagnosed with autism. This “MediCal effect” has diminished over time, while the other factors have remained consistent. The researchers’ analysis found that these individual level factors did not account for the increased prevalence of autism diagnoses.

What does that leave? Community level factors. In sum, these factors found that wealthier families in wealthier neighborhoods had higher prevalence of autism but hit a ceiling after 1994 of 40 per 10,000. The poorer families living in poorer neighborhoods have seen their rates rising since the mid 1990s.

Further analysis on the level of severity of autism underscore that the higher SES neighborhoods had much more “identification and ascertainment” of the autism diagnosis than the lower SES neighborhoods: the higher SES areas had much higher rates of the less severe and harder to diagnose autism cases. What this means is that the more resources you have, the more likely it is that your child will receive medical attention and diagnosis, which leads to the receipt of support services for the child. It’s not that being wealthier causes autism, but wealth is instead correlated with greater access to health care in the first place. Having an autism diagnosis can mean the difference between receiving treatment in school or simply being regarded as someone with behavioral problems.

Lower income families are gradually catching up. Analyzing the rates over time as they increase, it appears that the increase is due to better “identification and ascertainment” in the poorer neighborhoods as more awareness and services become available.

Hearing that there is a massive increase in some phenomenon is scary, but it is important to understand why the pattern might exist if it is indeed an accurate pattern. Comparing the news to recent high- quality scientific studies on the same phenomenon can help us better understand what is going on.
In this case, the research of King and Bearman suggests while the existence of autism may not actually be rising, it is the community dynamics, opportunities, and resources that can help us understand why diagnoses seem to be increasing.

What other studies can you find that shed light on this phenomenon?


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I liked the part about the wealthy families versus the poor families. I think that it is interesting how things such as income and whether the parents are educated play roles in diagnosing autism. I think it is ridiculous.

Very interesting article... I am quite interested in this topic and cannot wait to see what the future holds in terms of identifying the actual cause. I recall that not too long ago, childhood vaccines were blamed for causing autism, which created a fiasco in the world of pediatric medicine (especially when some parents are more inclined to listen to a certain actress rather than medical professionals).

This was a very informative article. My youngest brother is moderate to high functioning autistic, diagnosed at 3 years old (in 1989) and is attending school at a junior college close to home. I worked as a school nurse for children with autism, asperger's and other developmental disorders. From what I've learned through personal and work experience, there can be different factors as to how or why a child is born with autism; high levels of stress during pregnancy, older parents, prenatal drugs or alcohol use. The more we learn about autism the more we can help children and people with the right support.

I wonder if anyone has researched exposure to EMF (electro-magnetic fields) as EMF exposure rates are also dramatically higher, and would correlate with socio-economic classes as higher density living makes exposure more probable. When I travel I always carry a Trifield meter to avoid high risk exposure areas, mainly at hotels, but sometimes also at the work-site. In Europe and other countries, EMFs are regulated, but in the US, it's still the wild west. National Geographic had a good story on the increasing likelihood of EMF hazards, but it wasn't conclusive with regard to specific medical impacts. EMF exposure is definitely an area rife with opportunity, for new medical research.

Recent figures in Utah place the mark at 1 in 38. In 2006 a fact was reported than more than twice as many autism diagnosis are clinically diagnosed retardation. So we might need to brush up on what the data is saying and check our arithmetic. Is the 1/100 figure one section part in three?

Then you have to delve into the lowing of our scholastic curve of mental measurement. A lot of memory dysfunction is hiding there--how easy it is to skip through our public play school system now, and the rates of remediating elementary subjects. University math departments are partitioning into two departments, one re-teaches everything secondary and elementary schools can't achieve anymore. No one is scrutinizing the domain of public educators and how basic intelligence is turning up there as a factor of significant loss in the population.

The program did what it could to again, be the first source ever in mainstream television programming, in the search for environmental causes to mention tap water and show a kitchen sink faucet being opened as well as questioning what might be in the air. But that was it. The rest of the program focused on the errant expectation sudden pandemic phenomena can parallel drift in something as old and complex as the genome of a biological organism. There is no comparison of significant time scale for such across the board mutation, and statistics just within the earlier 20th Century found 1 in 10,000 was the rate of pronounced cognitive impairment.

Subsequently the modern history of congruent pathology in infants, anoxic sleep apnea during a time where there used to be a national SIDS workshop held annually in Seattle Washington, fails any sense that is left for medical research into autism, let alone the absence of any studies so far to track oxygen levels in infant blood now that oxygen sensing can be done easily and non-invasively with optoelectronic sensing through the skin; and to do so continuously through the first critical years of brain development. Science has to perform its own chore of debugging the methods and practice to which it goes either poorly applied or malpracticed—essentially the question in that case is what obvious search routes have been conspicuously abandoned for no reason in an attempt to enforce dogma.

Forensic toxicology, pathology, can easily identify signatures of brain cell loss followed by re-growth, leading to excessive white matter this program draws attention to. It is farcical if not criminally negligent medfraud to eliminate a search for the cause of elementary oxygen starvation and its mechanism. Why are infants falling into near lethal and lethal levels of anoxia during autonomically regulated respiration throughout natural periods of sleep paralysis–when voluntary control is naturally rendered incapacitated? Portuguese research confirms the pathology is unique to the victim and not inherited from either parent along the identifier tag of fetal brain cell antibodies in autistic’s blood serum. That crosses on regrowth processes and negates tetragenetic origin.

Why isn’t the brain stem being investigated?

Why is a false claim of classified military chemical weapons research blocking the identification of fluorine as the prime suspect–and just who is shooting off their mouth and swaggering with that ruse of ‘national security’? We have to be cautious and anticipate how completely different issues are contested behind closed doors, imparting restrictions to what protections our officials can invoke. The Patriot Act has unpublished sections the general public is not allowed to see. They will make up any excuse and play whatever card they can, and most of them are likely illiterate playboy politicians with a 6th grade understanding of world history, war history and the evolution of military technology or its widespread and commonly understood public domain. They are easily duped fools effortlessly made to lick military boots and impostures of authority–because they are vain, inept cowards.

I will finish this comment by comparing this crisis to a Civil Defense Crisis of immediate national emergency proportions, as if there were still imminent threat of nuclear war from our recent past. Warfare is also miseducated in this society. It comes in many forms and is carried out by many means to attack and destroy civilization. It is also an ethnically biased foible, fluoridation’s syndicate is staggering in its warcrime exploits to trivialize arch villains from the bootlegging era still made out to be the worst criminals of all time. It is a stain on all our institutions and government that will never be lived down.

But we can still 'do the math' on the threat to American Medicine.

Buzzword 'autism'--not invented here.

Sorry, I was referring to last night's "Autism Decoded: prevention and therapies" on KUEN-9.

Thanks for your blog.

Could the increase in population have anything to do with these results?

This is a very interesting article indeed. Thank you for shedding some much needed light and wisdom on the fact that newly acquired information and research must be analyzed thoroughly, and cannot be ascribed to certain causes without definitive scientific proof. Simply because variables show a correlation, whether negative or positive, with a certain phenomenon doesn't indicate there is any type of cause-effect relationship whatsoever; it simply suggests that in some way, they are linked.

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