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Awaiting Autism Prevalence Numbers: What Did the CDC Know and When Did They Know It?

Posted Mar 01 2014 12:00am

CdcpoliticsManaging Editor's Note:  New CDC autism prevalence numbers due out later today. Mark Blaxill wrote this in 2009. How many children have been diagnosed in 5 years?

By Mark Blaxill

With the recent announcement of the "largest ever" study to investigate the causes of autism, run through Kaiser Permanente (the HMO that lost vaccine safety data implicating thimerosal in harming children) and led by Lisa Croen (the epidemiologist who first attempted to deny the autism epidemic with faulty data), sometimes you just want to shake your head and wonder, what on earth is going on down in Atlanta?

The Centers for Disease Control (CDC) was once a proud and prestigious agency, staffed by the most elite corps of disease fighters on the planet, manning the front lines of the most threatening health problems facing mankind. Today, riven by dissension and ridiculed by many, the CDC has made a mockery of itself in failing to get to the roots of the most critical public health challenges of the day, including, but not limited to, autism. The consequences of its failures are profound. Morale has deteriorated and Congress has been investigating the agency for months.

Reflecting their loss of trust in the CDC's objectivity, autism advocacy groups have actively lobbied to reduce (and even zero out) CDC funding in the Combating Autism Act. The CDC has dual responsibility for monitoring vaccine safety and promoting the vaccine schedule; at the same time it's also responsible for surveillance on diseases like autism. In light of widespread concern over the link between autism and vaccines in the autism parent community, when the CDC announces that it's launching a new effort to find the cause of autism, it's hard not to think of OJ Simpson offering a reward for finding his wife's killer.

It was not always so. Indeed, in the midst of the AIDS epidemic, it was the CDC that took the lead—often against the intransigence and conservatism of NIH researchers—in tracking down the causes of the AIDS epidemic and taking steps to reduce its toll on society. For many years, CDC was held up to the world as a model government agency. Yet in autism, we have truly seen the downward spiral of the agency reaching its nadir: defensive, secretive and non-responsive to a health crisis in full flower. There are undoubtedly larger forces affecting the agency and its leadership. But if (as I believe to be the case) there are turning points in the lives of large institutions, critical crossroads at which difficult choices are made, then the CDC's handling of the autism epidemic is certainly one such turning point. Poor choices at crucial moments can lead, not only to negative consequence on a specific issue, like autism, it can cause the institution to lose its way. In a way, autism has been both a strategic and a moral problem for the CDC. For it's in the autism epidemic, I would suggest, that the CDC has truly sold its soul.

All of which leads me to ask the question, when did the CDC make this choice? What was the point in the history of autism when CDC leaders had the chance to honor its long history and raise the alarm over the autism crisis? Some would point to the infamous Simpsonwood meeting in the summer of 2000, where evidence of thimerosal's neurotoxicity, already tampered with in ways unknown to the meeting participants, was swept aside. I have certainly been in the forefront of the critics of the CDC work on vaccine safety issues, but I believe the CDC was already well past the turning point by Simpsonwood. I would suggest we need to look a bit earlier to find the CDC's crossroads in autism. For that, we need to look couple of years before the summer of 2000 and a bit further north.

The CDC lost its way on autism in Brick Township, NJ.

Three years ago, I attended a presentation outside of Boston given by Marshalyn Yeargin-Allsopp, the CDC's lead autism epidemiologist. In the course of a lengthy party-line talk about autism ("we simply don't know if autism rates are going up or if it’s just better diagnosis"), she said something that surprised me. "About ten years ago, we began to hear concerns from around the country that people were seeing more cases of autism", she said. I raised my hand from the audience and suggested that maybe ten years was enough time to move beyond the stage of ignorance on something this important. She snapped at me, a revealing moment in itself, and plowed through the rest of her 200 page presentation without pausing for a breath (or another question). But her comment got me thinking. Certainly, the CDC, the agency on the front line of all emerging public health problems from HIV to SARS to e. coli in a bad crop of California spinach, would have had at least some idea that there was an autism problem far before any of the rest of us did. And that leads me to my question for the day.

What did the CDC know about the autism epidemic and when did they know it?

It's a crucial question. For it is in the specific decisions that the CDC made-- when they proceeded from uncertainty, to confusion, to (perhaps if we're charitable) error and then to a policy commitment--that we might find that fateful moment of moral choice: the moment when CDC chose to put its own bureaucratic agenda ahead of our children. And from Yeargin-Alsopp's intriguing comment, I now knew that CDC was at least beginning to hear reports of rising autism rates around the year my own daughter was born, in 1995.

I know little about the CDC's activities in the years up to 1997, and there are few signs of a broader recognition of an autism problem that one can find before then. But in the fall of 1997, at a parent support group in eastern New Jersey, a few people started commenting about how many new autism cases seemed to be cropping up in Brick Township, and how there seemed to be an unusual number of 3-4 year old children with a new autism diagnosis. One of the attendees at the support group, a mother named Bobbi Gallagher who had two young children with autism, was struck by this coincidence. Living in New Jersey (although Brick is on the Jersey Shore, not the polluted stretch of highway along the New Jersey Turnpike that makes a mockery of New Jersey’s nickname, “The Garden State”), the thought of environmental contamination came naturally to mind and she wondered if there might not be a cluster of autism cases in Brick. Perhaps, she thought, there was something in the water. So she resolved to do something about it. She decided to send around a survey to see if she could count the autism cases in all of Brick, a town of some 70,000 people.

So as the new 1997 school year was starting, Bobbi Gallagher distributed her survey form everywhere she could think of in town. And in a few short weeks, she got a surprising result. Based on the responses to her impromptu survey, she counted over 40 autistic children in Brick Township alone and over 30 who were just three or four years old. Armed with these results, Gallagher formed a group called the Brick POSSE (Parents of Special Services and Education) and organized a meeting at the local library a couple of months later. They contacted Eric London at the National Alliance for Autism Research (NAAR) who in turn invited a number of academic epidemiologists. To a full house at the library meeting, Bobbi Gallagher shared her findings. One of the epidemiologists present, Craig Newschaffer, decided the numbers were disturbing enough to contact the New Jersey Department of Health and Senior Services, who in turn contacted the CDC. In the meantime, the Brick POSSE arranged a meeting with their congressman, Rep. Chris Smith, who invited them to a meeting in his office in Washington.

Within weeks, a more organized response took shape. Bobbie Gallagher received an invitation to another meeting in Washington, this time in New Jersey Senator Robert Toricelli's office. Gallagher remembers the date for this meeting vividly, April Fool's Day, 1998. And when she walked into the room she was astonished at how quickly plans had emerged. She had expected again to play the role of supplicant, pleading with the government officials to take action. Instead, she found a prompt and aggressive action plan being put on the table. In the room that day were representatives from multiple departments within the CDC who had come to the Senator's office equipped with a multi-part plan, the first part of which was a prevalence study for Brick Township, an in-depth survey of the town's autistic population that would pick up where Gallagher's survey left off. CDC had identified a core team of staffers to lead the effort, including Jacquelyn Bertrand and Marshalyn Yeargin-Allsopp from the National Center on Birth Defects and Developmental Disabilities (NCBDDD) and Frank Bove from the Agency for Toxic Substances and Disease Registry (ASTDR). Their proposal: to diagnose every child with autism in Brick Township between the ages of three and ten years old. They would start canvassing for cases and conducting interviews beginning with the start of the 1998 school year in September. And they planned to move quickly (at lightning speed really), to have their initial results ready by the end of the year.

They were true to their word. Two diagnosticians, Dr. Bertrand and Dr. Audrey Mars from the nearby Robert Wood Johnson Medical School, spent several days a week diagnosing children in the fall of 1998. And by January 12, 1999, the CDC had confirmed the findings of Gallagher's initial survey. Out of an initial estimated Brick population of 6,000 children from 3-10 years old, they had found over 40 cases of autism, giving a preliminary rate that was 12 times the estimated prevalence in the rest of the country. "I think there is a cluster here. I don't know why," lead investigator Bertrand said in an article by the Associated Press the next week. "If [we find] it's something that can be taken out of the community, that will be done," she said. According to AP she also added another intriguing tidbit: that "the researchers are eager to solve the puzzle here because of escalating calls the last few years about possible, but less credible, clusters elsewhere in the nation."

It all seemed to Gallagher like a dream: the cavalry had arrived and somehow they were going to get to the bottom of the issue. But then, something strange happened. Suddenly, the lines of communication with the CDC team went dark. After several months of intensive planning, intensive collaboration and rapid response, the CDC team told Gallagher that they were not at liberty to discuss the results with the parents any longer. According to Gallagher, one of the CDC staffers informed her that the mere mention of the word "cluster" had provoked a reaction from the higher ups within the CDC. Apparently, there was now even a debate as to whether they could use the word "elevated" when describing the prevalence rates. So from January 1999, until the release of the final study in April of 2000, there was no more interaction with the CDC. Not a single word.

Perhaps it was concern about the legal questions raised if there was indeed something in the water (class action attorneys had begun recruiting local families). Perhaps the Brick results weren't a cluster after all but part of a larger pattern that caused a more generalized concern within CDC (maybe it wasn't the water after all, since in February of 1998 the Lancet has published Andy Wakefield's controversial study implicating vaccines in autism). But there was no doubt about the silence coming from Atlanta. Something had changed the behavior of the CDC team. And it raises an interesting question. What did the CDC learn about autism rates in Brick Township and what did they do with their newfound data?

--
In Part 2: a discussion of the specific numbers in CDC's Brick Township report and what they should have told the world about the autism cases that they found in Brick.

From the start of their activities in the Brick Township New Jersey autism study, the CDC's approach had been nothing short of diligent and competent. They responded rapidly to an expression of community concern and fielded a team that began what seemed to be all the right kind of work on the ground. The team generated a response within weeks of mobilizing. They held a press conference to express their support for community concerns about elevated autism rates. If not a virtuoso performance, it was certainly professional.

Then something changed. After their January 1999 press conference, the CDC team went underground.

After many months of active communication and prompt response, they ceased all communication with Bobbie Gallagher and other member of the Brick POSSE that had first noticed the surprisingly high number of autism cases in 3-4 year olds in Brick. Team members explained that higher-ups were concerned about the way the team had communicated their findings publicly, using the terms "elevated" and "cluster" in describing the autism situation. Vague political rumors circulated as an explanation for the new sensitivity from Washington DC. But whatever the cause, it wasn't until well over a year later, April 2000, that the CDC's Brick study team would resurface. And when they did, all talk of a cluster was gone. All concern expressed in mid 1997 for the surge in 3-4 year old kids (who were 4-6 years old in 1998) was gone as well. Politics and public relations priorities, it seems, had taken precedence.

There was, to be sure, more work to be done after January 1999. The team added more autism cases to its count of "over 40" reported in their first press conference. By the time of their final report in April 2000, the CDC had identified 60 cases of autism spectrum disorder (ASD) in a population of just 8,900 children between the ages of three and ten. This rate, 1 in 150 children, was the highest autism rate ever reported anywhere in the world up to that time, and might even have understated the real rate. Bobbie Gallagher believed the CDC's count left out quite a few families that had left Brick and that an approach that accounted for migration would have yielded over 70 cases.

But by early 1999, the CDC team had virtually all the information it would ever get on autism rates in Brick. What did they do with that information?

They had two questions they really needed to address in any final report. The first was the issue of locally elevated environmental toxins: the kind of industrial contamination that might have provoked a Brick autism cluster. The Brick POSSE certainly believed that they had discovered a cluster. Bobbie Gallagher thought that there was something in the water. And so there was great concern over specific chemicals that might be harming their unborn children. Gallagher expressed skepticism that vaccines had anything to do with her own children's autism. "It's possible that vaccines are a factor in some families, but I don't think that's what happened with my two children", she told me. "I brought two autistic babies back from the hospital."

So with the support of local parents, the CDC team focused on water quality. And they had a specific hypothesis about the nature of the contamination. The CDC team member from Agency for Toxic Substances and Disease Registry (ATSDR) had written a paper just a few years before that linked trihalomethanes (THMs) to a variety of birth defects, including neural tube defects. Frank Bove (who according to Gallagher had two autistic children himself) believed that these neural tube defects could be the key missing piece in the puzzle. Bove consulted with Patricia Rodier, a researcher from Rochester who had worked on toxins that she believed could cause neural tube defects in autism. And the ATSDR report on Brick went on at some length about their concerns over THMs (a pervasive toxin that Bobbi Gallagher knew was elevated in the local water supply) and neural tube defects. But in Bove's particular approach to the analysis of Brick's autism cases and THM exposure, there was no smoking gun. In fact, any way they cut the data, they could find no link between the elevated THM rates in the local water supply and the local autism cases.

In short, ATSDR's quest for a singular environmental toxin that might provide an easy explanation for Brick’s autism problem came up empty. So despite autism rates in Brick that were far higher than anything ever seen before, CDC and ATSDR were unwilling to declare the Brick community an autism cluster. To this day, autism rates in NJ are among the highest in the nation and among the highest reported anywhere in the world (one recent survey reported a rate of 1 in 93 children). But in part because no obvious and easy toxin presented itself for blame and removal, the CDC took no position. And they pursued the issue no further.

The second question on the CDC's plate was the question of the rising trend in autism rates. In Gallagher's support group meeting in 1997, everyone had remarked on the unusually large numbers of 3-4 year old cases. And by January of 1999, the CDC had a great deal of data on ages and birth years of their affected population. Their conclusion on trend? In a classic bit of statistical doublespeak, they declared that there was no support for higher autism rates in younger children. "Age-specific rates were calculated for preschool (3- to 5-year-old) and school-aged (6- to 10-year-old) children...CIs [confidence intervals] for the 2 age groups overlapped, indicating that the prevalence rates for the 2 age-groups were not different."

But how could this be true? It seemed to fly in the face of everything observed by the parents and professionals on the ground, not to mention the hints that the CDC had been hearing for years about rising autism rates all over the country. Unlike the search for environmental toxins in the water, there was nothing all that complicated about the trend. Either there were more cases or there weren't. And if the rates were rising, however hard it might be to pin down the cause, it was important to keep looking, because too many children were sick.

In mid 2002, it occurred to a few of us at SafeMinds that the CDC's conclusion in their Brick Township report was likely to be flawed. Not only was the rising trend apparent in their data, there were also a number of odd elements in their design and write up. For one thing, the age groupings were strange—separating the sample into two groups of unequal size, 3-5 and 6-10 year olds. Why would they not divide the population into equal sizes, putting 3-6 year olds and 7-10 year olds together? For another, as I had learned in examining Lisa Croen's claims of diagnostic substitution in California, autism time trends can be easily misinterpreted if the analysts don't factor in the lag time that the youngest children face in getting recognized (the technical term is "ascertainment bias"). What if the Brick team, as most survey teams had done before them, had simply undercounted three year olds?

So Sallie Bernard sent an email to Frank DeStefano of the CDC, whom she had met at a recent meeting. She asked him what would happen to the Brick rates with 3 year olds removed. And he responded in a May 10, 2002 email, "For overall ASD, the prevaleces (sic) were: 10.2 per 1,000 among children 4-6 years old, 4.4 per 1,000 among those 7-10 years old." Sallie promptly thanked him and, noticing that this rate differential seemed larger than the published study, asked him if these were statistically significant. DeStefano's response was telling.

"The results are based on 35 cases out of an estimated 3442 children 4-6 years of age, and 19 cases out of an estimated 4272 children 7-10 years of age. The difference in prevalences noted below is statistically significant." [emphasis added] 

In other words the published conclusion changed completely if you simply removed a single age group, the three year olds.

Despite providing a stunning admission, DeStefano had still not given us what we really wanted, which was the breakdown by age category. So Sallie asked him again. And a few months later, she received this response from Marshalyn Yeargin-Allsopp.
 
"Hi Sallie, Happy New Year!  Frank Destefano has asked me to respond to your question about rates of autistic disorder for Brick Township.
They are: (per 1000), rounded

3 yo    2.5
4 yo     6.1
5 yo     7.8
6 yo     7.0
7 yo     6.4
8 yo     2.0
9 yo     ----
10 yo   ----
TOTAL   4.0"

This was even more of a shocker. What Yeargin-Allsopp had revealed was that there was not a single case of full syndrome autism in the entire Brick Township population of nine and ten year olds. This was a different case definition than the one DeStefano had given us, which included PDD NOS and Asperger's cases. But it provided clear statistical support for the parental concern over the unusual number of cases in the younger children. And here it was in black and white -- the CDC had this data all along.

So on the second crucial part of their charge, the evidence was clear. The CDC knew there was an autism epidemic in Brick Township in 1998. And they neither said nor did anything about it. In fact, they did exactly the opposite: they used a clever bit of statistical trickery to cover it up.

How clever was it? Well once you have the real trend data, you can figure out how hard the CDC had to work in order to report a result that said there was no trend. And in the months between January 1999 and April of 2000, the CDC figured out just about the only possible way to claim that autism rates weren't rising. They took the 6-10 year group, one where autism rates rose from just plain zero to 1 in 143 and put them into one bucket. They took the 3-5 year old group, which due to ascertainment bias had a declining rate (from 1 in 128 to 1 in 394) and put them into another bucket. And they compared these two ratios and reported that there was no significance to the rising trend. And if you run the statistics on just this arrangement of the data, they are correct.

But the problem with this approach is that it's too clever by half. Virtually every other reasonable grouping shows a significant increase.

•  DeStefano's analysis comparing ASD rates in 4-6 year olds with 7-10 year olds gave a significant increase with a 99% confidence level (statistical "significance" kicks in at 95% confidence).

•  If you take the full syndrome autism group and divide it into two equally sized buckets, comparing 3-6 year olds and 7-10 year olds, you also get a significant result with 99% confidence.

•  If you take the 5-6 year old group of full syndrome kids and compare it to the 9-10 year old kids, you get an even more significant finding, more than 99.9% confidence.

As the saying goes, there are lies, damned lie and statistics. If this wasn't a cover up, I don't know what else to call it.

For some, myself included, a picture is worth a thousand words. And if the problem in Brick was indeed more than a cluster, if there was a broader national trend towards rising autism rates, then what matters is not just the age of the Brick children, but their birth years. A more consistent national trend would be revealed if we could find similar changes in autism rates in the same birth years. And a clear picture of the increasing trend would help us identify the kinds of environmental causes that weren't just local elevated toxins in the Brick water supply.

The Brick study provided the first data that could paint this picture and show the specific turning point in autism rates. The age groupings in the Brick team's study were based on the "attained age in 1998", so the ages are easily converted to birth years. Every child who attained the age of three in 1998 was born in 1995, the four year olds were born in 1996 and so on, up to the ten year olds, who were born in 1988. The chart below shows the data Yeargin-Allsopp sent to Sallie Bernard and compares it to the data the CDC published. As you can see, the rates exploded in the 1990-94 birth years and then dropped off a bit in the 3 year olds, due to the ascertainment effect. Looking at the numbers year by year (the dotted line), and comparing them to the published rates (the flat solid line), it's easy to see just how deceptive the CDC's reported findings truly were.


Brickjpeg_2

As I said in part 1, there is a moment of truth in the life of any institution. And here was the moment for the CDC, the crucial point "when they proceeded from uncertainty, to confusion, to (perhaps if we're charitable) error and then to a policy commitment.” In this case, attributing the stage after confusion to error is more charitable than the CDC deserves. Faced with the evidence pointing to the worst childhood epidemic in modern memory, the CDC chose to cover it up. When you have the real data, the numbers literally jumped off the page. But the only published finding was "no trend", the only commentary, bland reassurance.

What kind of pressure would make professional people do something like this? After such a diligent and responsive start, such a spirit of openness and candor, what moved the CDC team to put their head in the sand and walk away?

It's worth remembering what was happening in the period between January 1999 and April 2000. Most of Washington DC was consumed with the impeachment proceedings ending in Clinton's acquittal on February 12, 1999. In March 1999, just two months after the CDC press conference, the California Department of Developmental Services issued their own report showing the sharp increases of autism rates in California. A few months after that, in July 1999, the Public Health Service announced its plans to remove thimerosal from childhood vaccines. So as the team completed their work, it's almost certain that the public posture the CDC would take in the Brick report took on added importance. After all, as the chart shows, the real surge in Brick was in line with the expansion in the required immunization program, certainly correlated with thimerosal exposure. So there's little doubt that the CDC was worried about its own role in provoking an autism epidemic. At the same time, as the durable evidence of elevated rates in New Jersey have shown, the local trend was also perhaps part of something more specific to the Brick environment. Speculation aside, however, this was a moment of choice. And in a moment that required continued professionalism, openness and candor, something else happened. It was pretty pathetic.

In April 2000, after many months of silence Bobbie Gallagher got a call from the CDC. They were coming to town to release their study, both the CDC prevalence report and the ATSDR analysis of local toxins. They came to her house, gave her two lengthy documents, asked her to respond in the moment if she had any questions. They confessed that the autism rates in Brick were three times higher than rates they were seeing elsewhere. But they had no plans to do anything more about it.

Then they left the Gallagher's' house to go to the public meeting, where they took the same basic approach. They made no presentations, simply put the two reports on the table and made themselves available for questions. They had two sessions, one for the press and one for the residents.

And at the front of the room, Gallagher reports that there were two groups of people. One was the familiar team, Bove, Mars, Bertrand, who had done the work and been part of the initial outreach. Next to them was another group "we had never seen before." Their job, according to Gallagher, was to watch the original group and "make sure nobody said the wrong thing." At 8:00 PM, the session ended and "you've never seen a group leave a room so fast."

"And we never heard from any of them ever again."

Mark Blaxill is Editor At Large for Age of Autism.

Posted by Age of Autism at March 27, 2014 at 5:45 AM in Mark Blaxill Permalink

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