Tuesday, August 26, 2014

Did the CDC hide a link between vaccines and autism?

So there's an iReport article going around the Facebook circuit accusing the CDC of covering up a link between vaccines and autism. The allegations from the author "eplettner" are pretty serious: this person accuses the CDC of covering up evidence that the MMR vaccine causes autism.

Are eplettner's claims of a coverup true, and more importantly, is there a link between the MMR vaccine and autism?

As many of my Facebook friends have disovered, I love correcting factually wrong statements, especially strong ones. I like to do this regardless of whether I agree with the conclusion of one side or the other.  On a controversial topic like whether or not vaccines raise the risk of autism, there are plenty of statements flying around as fact. Many of these statements directly contradict each other... in this case, "The evidence now is convincing that the measles–mumps–rubella vaccine does not cause autism or any particular subtypes of autistic spectrum disorder." (link from a site claiming to draw this conclusion from the CDC study) and "CDC recognizes an increased risk of autism from MMR." from the iReport.

Finding correct conclusions requires starting with true facts. Unfortunately, the internet and human interaction in general allows true and false facts to be spread equally quickly. To make things worse, humans have a tendency to accept claims that support what we already believe, while rejecting stronger claims that don't fit with our beliefs. This is known as confirmation bias.

So what's up with the CDC study?

The original CDC study is DeStefano et al. (2004). The study compared over 600 children with autism to non-autistic children to determine whether the time of receiving MMR vaccination was linked to autism. The study determined:
"Similar proportions of case and control children were vaccinated by the recommended age or shortly after (ie, before 18 months) and before the age by which atypical development is usually recognized in children with autism (ie, 24 months). Vaccination before 36 months was more common among case children than control children, especially among children 3 to 5 years of age, likely reflecting immunization requirements for enrollment in early intervention programs."

One person, Dr. Brian Hooker, believed vaccines gave his son autism. He got the original data from the CDC study, and reanalyzed it (Hooker, 2014) from the original study using a different statistical method and came up with similar data: no increased risk of autism from vaccines given before 18 months or 24 months, but slightly higher rates of autism for the group of individuals receiving vaccines before 36 months. Hooker, however, asserted the 36-month discrepancy was not due to parents getting their autistic kids ready for school.

Hooker also broke down the data by race and gender. While he only had a few African-American males in his study (which tends to make analysis unreliable), the interesting results were confined to this group, showing a 3.4x rate of autism in African-American boys vaccinated between 24 and 36 months. White males, and all females, showed no link between autism and age of vaccination.

I'm not a statistician, so I can't compare the two methods, but vaccine author David Gorsky has compared them. Skip to the section "Brian Hooker's "Reanalysis"." He notes that the CDC data set wasn't designed for the type of analysis Hooker did, and in particular, the number of African-American children was probably not enough to draw reliable conclusions about their group.

 So to answer the original questions:

Did the CDC cover up their data?

It seems unlikely that there was a "coverup" of a link between age of vaccination and autism, because DeStefano indicated this in the original study: a link between vaccines between 24 and 36 months and autism. So no, there was no coverup.

Is there a link between the MMR vaccine and autism?

DeStefano, pointed out that autism tends to manifest before 24 months, so parents of such kids often get their vaccines in right away to take advantage of school programs for their kids. This may explain the discrepancy, but this isn't certain, and we must rely on other studies to determine this.

Fortunately, many other studies have been done on MMR and autism. The best one is a Danish study that analyzed data on nearly the entire population of Danish babies over a period of 8 years and found similar rates of autism in vaccinated and unvaccinated children.  If age of vaccination did cause autism, then we would see fewer autistic children in the unvaccinated group, but unvaccinated children were diagnosed at similar rates. Even Hooker's reanalysis, flawed or not, reconfirmed that girls and white boys have no increased risk of autism due to age of MMR vaccine. There is no causal link between MMR vaccine and autism in the general population.

What about the claims in the iReport article?

The iReport article is titled "Fraud at the CDC uncovered, 340% increased risk of autism hidden from public". The article cites quotes from a Dr Thompson at the CDC, but it seems these quotes have come through Drs. Hooker and Wakefield via interview soundbytes. So are Thompson's quotes true - did CDC hide data? Dr. Hooker had to actually massage his data to even have enough African-American males to study as a subgroup. Hooker modified the pool of these boys from pre- 36 months to pre-31 months so that he'd have over five kids to look at. As Dr. Gorsky points out, "You cannot, and must not use small numbers to make big assertions." So to claim the CDC is hiding anything about African-American males is absurd - they followed good procedure and didn't report on something about which they had insufficient data. Yet the article claims that the original DeStefano study is "fraudulent" and cites a Change.Org petition and hashtag campaign to bolster the idea that their claims are true.

The article throws in other claims in an apparent attempt to prove a connection between vaccines and autism. In one such claim, it notes that autism is an admitted "secondary cause" of vaccine injury. The article fails to explain that this is a side effect of very rare injuries that don't statistically affect the rate of autism.

Conclusion - past and future research.

A good scientist seeks the truth, in this case, through careful study. Ever since the original claims of Andrew Wakefield that MMR vaccine causes autism - based on data that Wakefield falsified in an actual fraud - there have been many studies done on the possibility of a link. Both the original CDC study by DeStefano and the reanalysis by Hooker contradict Wakefield's claims of a general link, and other studies have researched other vaccines and possible vaccine-autism links and found nothing. The Hooker study provides a glimmer of possibility of a link between vaccination timing and autism in African-American boys, one that will doubtless be studied more thoroughly in the next ten years. When such a study is concluded, our human tendency will to either accept it if it agrees with what we believe, or deny it if it disagrees with what we believe. Fight this tendency. Don't let confirmation bias get in the way of finding the truth.

Saturday, April 18, 2009

Small companies making gains on large corporations

At the Harvard Business Blogs, Peter Bregman gives a couple of compelling anecdotes of small companies beating out large ones in competition for major contracts. Small businesses offer the promise of relationships and good service and responsiveness. The uncertain economy gives large companies the threat of layoffs and financial turmoil. The advantage is reliability.

Monday, April 6, 2009

Final Four

The Kansas City Star writes about the Spartans' rise to the national championship. Looks like former GM chairman Rick Wagoner was instrumental in bringing the Final Four to Detroit, but he wasn't able to make it to the games this weekend. The article doesn't mention why. I'm guessing he's keeping a low profile right now. I feel bad for him.

I'm hoping Wagoner's Final Four efforts are a success and that a Spartan victory buoys not just the hope but the hard work and grit of southeast Michigan. If this state is to succeed, it must do so like Izzo's team - no whining, just hard work.

Wednesday, March 18, 2009

Innovative production beats marketing.

More on the small-business vs. big-business front:

For decades US corporations have been abandoning the production business in favor of the supposedly more profitable business of branding and marketing. But this strategy is coming back to bite US laptop makers. Wired reports that Taiwan companies responsible for designing and building laptops for Apple, HP and Dell have taken the industry by storm with their innovative netbooks - low-power, low-cost laptops perfect for computing on the go. Or, as Wired's Clive Thompson puts it (bold mine):

In the US, we regard branding and marketing - convincing people what to buy - as core business functions. What Asustek proved is that the companies with real leverage are the ones that actually make desirable products. The Taiwanese laptop builders possess the atom-hacking smarts that once defined America but which have atrophied here along with our industrial base. As far as laptop manufacturing goes, Taiwan essentially now owns the market; the devices aren't produced in significant volumes anywhere else... "When I talk to [the Taiwanese] now," [researcher] Shih laughs, "they say, 'We outsource our branding and sales to them."

But American manufacturing is far from dead. Once again, the innovation and flexibility of small business is filling the gaps left by corporations. Clive Thompson tells us in the same March issue how small-scale DIY manufacturing is making products never seen before - and growing by leaps and bounds.

Thursday, March 5, 2009

Starting a business in a recession

The recession can't stop entrepreneurs from starting new businesses. With lower costs and customers looking for good deals, the troubled economy is a popular time for laid-off workers to start their own businesses. See the Reuters report.

Thursday, February 26, 2009

You don't need a credit card. Really.

It's true, right? You need a credit card for modern middle-class life. You can't get along without it. Even an astute friend, one who doesn't follow trends for trends' sake, was caught up in this lie. She posted a Facebook link about how to properly use a credit card. If a credit card had a single redeeming quality, it would be a great link.

But no, there's no reason to have a credit card. Many real-world financial counselors will tell you why:

Say you use your cards responsibly. You pay the whole balance every month, you have no annual fees. You get 2% back and even free tools and perfume every year if you spend enough. You're the shining example of good credit card user, the one who takes advantage of the credit card company and makes money on the bargain. No: you're still a loser according to research - or "a sucker" according to the Boston Globe. You're spending more money thanks to impulse buys. Switch to cash and you can truly come out ahead. More money left over at the end of the month to save, or maybe spend on something more carefully considered.

There are three more common objections, to which I found some answers:

Q: "But not everyone takes cash!"
A: When necessary, use a debit card. You can use them online or anywhere credit cards are accepted. Still use cash when you can, like at the restaurant, or your bill will be magically larger when you're done ordering.

Q: "I need to build my credit!"
A: "Debt is dumb" says Dave Ramsey - never borrow money. OK, just for a house you probably can't buy it any other way. But always buy a house with a large down payment and just a 15-year loan (if you can't, face the fact that you probably can't afford the house). With a good down payment your credit matters a lot less. Is it worth spending years maintaining just the right amount of debt, shining up your credit rating but losing money (see above), for a slightly lower interest rate?

Q: "But what about emergencies?"
A: Plan for them. Build an emergency fund. Save 3-6 months income in a savings or money-market account. Buy insurance (home, car, health, long-term disability, life, liability) as needed. If you're already in a financial emergency, there's other advice and encouragement, but for the rest of us: Cut up your cards, and start building your emergency fund today.

edited 2/27/09 for tone & wording.

Saturday, February 21, 2009

Prison population reduction

One percent of adult Americans are in jail or prison. The problem is worse in Michigan, which spends nearly two billion a year on the 11th-highest per-capita prison population. Lots of people are upset, but misconceptions of the problem will get in the way of fixing it, says John Pfaff. Read his Five Myths About Prison Growth, which concludes:

We need to stop admitting many minor offenders, even if they're serving only short sentences. We need to focus less on high-profile drug statutes and more on the ways small-fry drug convictions cause later crimes to result in longer sentences. Once we start admitting fewer people to prison, we should shift money from prisons to police. If this seems like tinkering, rather than a sweeping fix, that's because it is. See Myth No. 4: Reformers shouldn't waste their breath trying to turn us into Europe.

Governor Granholm wants to cut the prison population as a key part of balancing Michigan's budget.