Posted tagged ‘asd’

The latest in autism research

August 31, 2015

The Pediatric Insider

© 2015 Roy Benaroch, MD

Science: it may not always be the fastest, coolest, or sleekest way to get from one place to another. And it certainly is prone to dead ends and tangents. But if you want to really understand what something is all about, real science and real research are your best tools. Some great examples come from a few studies that came out this year about autism.

A British study from May, 2015 (summarized nicely here) looked at sets of twins, looking not only at diagnosed autism but at autistic behavior traits. Bottom line: autism is very largely genetic, as demonstrated by the higher association of autistic traits in identical twins. Since sets of twins largely share the same environmental and family influences, looking at identical (ie sharing the same genes) versus fraternal (sharing genes only as siblings) is a well-established way to separate out genetic and environmental influences. Using Fancy Math, the authors conclude that autism’s roots are found in one’s biologic make-up at least 74% of the time, and perhaps much higher than that. Studies like this will help future researchers concentrate on the most likely candidates for autism’s cause.

Another cool study, this one from the University of North Carolina, took the role of genes even further. We know that about 1,000 genes have been linked to autism—meaning that certain variations are more likely to occur in individuals with autism. What these researchers did is take that further, finding the exact functioning of one of these candidate genes. They found that the gene encoded for an altered protein that incorrectly flags other proteins in a cell for destruction. This causes the appearance of what are called ‘spines’ on cells in the brain—and, sure enough, we already knew that these spines were more common in kids with autism. It’s like connecting a circle—you start by figuring out which genes are present in autism, then figure out what they do, then confirm that the result of having these genes is present in children with autism. That’s how we go from understanding why autism occurs (a change in a gene) to how it occurs. And once we know how it occurs, we can start working on reversing or stopping the process, to preventing the altered gene from causing problems.

Studio 54The internet is a noisy disco of flashy memes, slogans, and catchphrases. And, of course, ubiquitous Google searches ironically misunderstood as “research.” But those sorts of things don’t help anyone really understand what’s going on. Want to understand and help families with autism? Support the science, not the noise.

Advertisements

Ultrasounds and autism: Another media scare!

June 6, 2013

The Pediatric Insider

© 2013 Roy Benaroch, MD

Emily wrote in about an article about prenatal ultrasounds and autism: “I saw this on The Daily Beast (Newsweek) today. Is the media trying to freak us expecting couples out or what? How big of a question is this in scientific circles or is this just sensational stuff? Sometimes I think there should be studies about how the internet causes anxiety disorders!”

A good question… and another post that I’m going to put under my new category, “Guilt Free Parenting.”

The Daily Beast headline and tag reads: “Are Ultrasounds Causing Autism in Unborn Babies?” and “Scientists are uncovering disturbing evidence that those sneak peaks at baby could damage a developing brain.”

I wonder how all of this accumulated hysterical, sky-is-falling reporting is damaging adult brains. As Emily said, the internet seems to cause anxiety disorders, and it’s articles like this that get everyone worked up.

First: autism is a complex neurodevelopmental disorder that causes problems with communication, social interactions, and repetitive behaviors, starting very early in childhood. The best current evidence shows that whatever’s gone wrong, it’s going wrong very early in life, possibly even before babies are born. There are strong genetic influences, and there is still a lot we don’t know about what causes autism and how to best treat it.

Autism is especially scary because we’re hearing so much about it. It may be as common as 1 in 50 boys, and it seems like the incidence is rising dramatically—but a lot of that apparent increase is because of an ever-widening definition of autism, combined with efforts at early detection and what’s called “diagnostic substitution” (kids who would have once been diagnosed with mental retardation or other disorders are now diagnosed with autism.) But whether the true rates of autism are increasing or not, it’s certainly a huge problem for families and communities, and increased awareness, early detection,  and early treatment are urgently needed.

Because the causes of autism remain unclear, there’s a lot of speculation about what might be going on. If you Google “causes of autism”—and please, please don’t do that—you’ll find all kinds of speculation about toxins and parenting styles and government conspiracies and evil doctors who are eager to profit by harming children. You’ll also find a few tantalizing, genuine leads, things that might actually make sense. Those are what legitimate researchers are trying to study.

So what about ultrasounds? It is true that prenatal ultrasounds are being used more commonly, and the rise in their use generally follows the trend in the observed rise in autism over the last 20 years. But that observation, alone, doesn’t really show that one thing causes the other. After all, over the last 20 years we’ve also seen a dramatic increase in cell phones, cable television, frozen food, Oprah, personal computers, and Starbucks; we’ve also seen a decline in the prevalence of cursive handwriting, licking stamps, and the Sizzler Steakhouse chain. Are any of these connected to autism, or to each other? Maybe. Maybe not.

Is there some basic science about ultrasounds that makes a connection with autism plausible? Again, maybe-sort-of. Research on the effect of ultrasounds on developing mouse brains has shown a difference in the way brain cells move and migrate—but those studies looked at ultrasound exposures for many hours a day, and mouse brains develop much more quickly than ours do. We’ve also got much bigger brains, and much more tissue between our babies and an ultrasound probe than mice. Lab research on the effects of ultrasound on moving cells or bubbles is similarly unconvincing—something to think about, but a huge leap from there to “ultrasounds cause autism.”

Several studies have looked for any direct biological effect of fetal ultrasounds on human children. A 1978 report looked at about 1000 infants of mother who received amniocentesis, ultrasound, or neither—it found no developmental effects of ultrasounds. In 1984, a different group looked at 425 children, finding no biologically significant differences among those who were and were not exposed to diagnostic ultrasounds. There are also many studies looking at potential ill-effects of ultrasound technology for diagnostic use in babies, children, and adults—there are none caused by the ultrasound itself. For those of you who’d like even more detail, an excellent review of these and many other studies about ultrasounds and autism is here (unfortunately the full article is behind a paywall.)

So what’s The Daily Beast talking about—are scientists, as they say, uncovering “disturbing evidence”?

This is what’s actually reported in the article, in order of appearance:

  1. References to a study showing that among low-risk pregnancies, routine ultrasounds don’t improve outcomes. This is true. It’s irrelevant to the title or thesis of the article, but it’s true. Media lesson #1: if you don’t have a study to prove your point, talk about a different study that says something else entirely.
  2. Ultrasounds drive up the cost of care. Again, correct. Again, irrelevant. See point #1.
  3. Women who undergo frequent ultrasounds are more likely to have a pregnancy where the baby is found to have growth restriction. Well, this is true. It’s also true that if you look outside you’re more likely to know if it is raining. Fetal growth restriction is diagnosed by ultrasound. If you don’t look, you don’t know it’s happened. But looking outside doesn’t make it rain; and looking at an unborn baby with an ultrasound doesn’t cause the baby to be small. And, in any case, this is again irrelevant to autism. See point #1.
  4. The author of the article has written a book in part about her assertion that ultrasounds are to blame for what she calls “an astronomic rise in neurological disorders among America’s children.”
  5. The mice studies I referenced before—those come up now, several paragraphs in, the first even remotely relevant material. The lesson here: if you are a mouse, do not get seven hours of ultrasounds a day.
  6. A neurologist named Manuel Casanova shares the author’s concerns, and says he and colleagues have been testing the ultrasound-autism hypothesis for three years. However, and this is important: after several technical paragraphs about his ideas, he’s uncovered zero evidence to support this claim. What he’s saying are generalities about brain development that are true, and he’s juxtaposing this against information about ultrasounds and information about autism, but he doesn’t in any way refer to any of his or anyone else’s actual research establishing a connection. These are ideas. Ideas are not evidence.

That’s it. The whole article.

Now, there is a reasonable point that I will agree with—prenatal ultrasounds do not necessarily improve the health of babies, and they’re often unnecessary. Vanity ultrasounds to take 3-D pictures of unborn babies use far more energy, and it’s not implausible that there could be ill-effects—things like this are not medical uses, and ought to be discouraged until there is definitive proof of their safety.

That being said, there is no evidence for a link between ultrasounds and autism, none whatsoever. It’s not being uncovered. It’s just not there.

More reassurance for parents on vaccines and autism

April 1, 2013

The Pediatric Insider

© 2013 Roy Benaroch, MD

First, it was the MMR-autism link—that turned out to be a complete fabrication, a fraud invented by a single “researcher” who made up his data. He was taking money from plaintiff’s lawyers, and he was trying to patent his own, competing vaccine. Too bad for the scare and the resulting surge in measles.

Then, the mercury connection. A mercury-containing preservative, thimerosal, came under scrutiny. To be safe, it was removed from almost all vaccines in 1999—and rates of autism didn’t fall one bit.

The most recent vaccine-autism link can be abbreviated as the “too many too soon” hypothesis, that somehow the antigens in vaccines “overwhelm” the immune system, leading to mischief. It doesn’t matter that the quantity of antigens from the current generation of vaccines is far fewer than what was used in the past. Those needles have got to be doing some harm, right?

The “too many too soon” idea never made any sense, from a logical or scientific standpoint—it’s well deconstructed here. The “load” on the immune system from ordinary life, from the exposures we all have from living in a world full of bacteria and germs, is hugely greater than the comparatively tiny exposures from vaccines. But the true, hardcore anti-vaccine propagandists have found their latest idea, and as usual they don’t need no stinkin’ evidence.

Still, there is evidence. For the many families who have sincere questions about vaccine safety, it’s good to have yet another study to add the mountain of evidence that vaccines are safe, and that vaccines do not cause autism.

Published in The Journal of Pediatrics this month, this study compared children with autism (including several subtypes) to typically developing children. They combed records to determine just how many vaccines and how many vaccine components were given, to see if they could find a link. Could increasing vaccine exposures increase children’s risk of autism?

No. Increasing exposures to the antibody-stimulating products in vaccines during the first two years of life did not increase the risk of developing any autism spectrum disorder.

At this point, the evidence for the lack of any vaccineautism link is overwhelming. Continued vaccine study for any sorts of side effects needs to continue, but the singular focus on vaccines as the cause of autism as voiced by some in the autism community has become a hindrance to genuine progress and a public health nightmare. Let’s keep our kids healthy. Make sure your kids are fully vaccinated, on time and by the established schedule. It’s time to put this vaccine-autism thing behind us, so we can speed up the progress towards better understanding, prevention, and treatment. I’d hope that’s something we could all agree on.

Mercury in vaccines: Changing perspectives, changing minds

January 2, 2013

The Pediatric Insider

© 2013 Roy Benaroch, MD

News from the vaccine world: The AAP has announced that it supports the WHO’s position that the mercury-containing preservative, thimerosal, is safe, and should continue to be used in vaccines.

The first I can recall hearing the word “thimerosal” was on a bottle of contact lens solution, as a teenager. “Does not contain thimerosal”, the container said. “Safe and gentle on eyes.” What was this thimerosal, and if it could hurt my eyes, why would anyone put it in contact solution?

Thimerosal has been around since the early 20th century, used as a preservative to prevent the growth of bacteria and fungi in sterile solutions. It is, objectively, phenomenally safe—no study has ever found a toxic effect of this stuff in humans at anywhere near the amounts that we’ve ever been exposed to it. We know it can prevent multi-dose vials of vaccines (and other injectables) from developing dangerous contamination, and we know how to safely use it in manufacturing and producing health products. It’s cheap, it’s safe, it works. So what’s the problem?

The problem is mercury. Thimerosal contains an organic compound called “ethyl mercury”. Though ETHYL mercury has a very low potential for toxicity, similarly-named METHYL mercury is an industrial pollutant that can cause neurologic damage and other problems, especially with high or prolonged exposures. But METHYL isn’t ETHYL, any more than ETHANOL (=ethyl alcohol, found in beer, causes drunkenness when consumed in ordinary amounts) is the same as METHANOL (=methyl alcohol, which can make you blind and dead if you drink just a little.)

Nonetheless, “mercury” is scary, and in 1999 the AAP and the CDC agreed that it would be safest for mercury-containing preservatives to no longer be used in children’s vaccines. And over a few years, that’s what happened. Vaccines were switched to be produced in more-expensive, single-use vials. It wastes a lot of glass, but you don’t need a preservative if a vial is only used once.

Once concerns about mercury began to swirl, a vocal segment of the autism community latched onto mercury as the cause. Despite removing mercury from all vaccines (except some flu shots), the rates of autism have continued to increase. There has never been any evidence of any harm from the mercury that had been used, and most of the autism community has moved on past the mercury idea. Worth looking into? Yes. Plenty of evidence that mercury’s not the culprit? Yes. Time to pursue other leads? Yes.

(As a side-note, based on a fraudulent 1998 paper some began to think MMR was an autism trigger. That has also turned out to be false. Ironically, no MMR vaccine ever contained any thimerosal. Still, the “mercury” and “MMR” media circus kind of intertwined and mixed up the stories, leaving parents breathless with unnecessary worry. Way to go, media.)

What have we learned since the removal of thimerosal from American vaccines in 1999? Autism rates have not decrease (they’ve continued to increase, perhaps even faster than before.) No evidence of any harm from thimerosal exposure has ever been uncovered. Extensive studies have supported the safety of the preservative, showing, for instance, that it is quickly and easily excreted from the body. It’s an academic point in the USA, anyway: thimerosal is not coming back.

But what about the rest of the world? We’ve got plenty of money, here, to be extra-cautious (or extra-indulgent of worry, perhaps.) But making single-dose vials of vaccines costs a whole lot more, and there is no practical, proven, safe alternative as a preservative for vaccines. So the same AAP that in 1999 suggested that the US stop using thimerosal is now saying that it’s OK for everyone else. I know: sounds dubious. But I think given what we’ve learned and confirmed about thimerosal’s safety, the AAP made the right call.

Detailed review from CDC

Long article reviewing vaccine-autism speculation