Tuesday, July 18, 2017

David Wallace-Wells, autism and bad science

David Wallace-Wells has been catching a lot of flack (most of it richly deserved) for his recent New York Magazine article on climate change. It is a hugely troubling sign when the very scientists you were claiming to represent push back against your article.

This controversy illustrates a larger problem with science reporting at the magazine. We already have a post in the queue discussing the neutral-to-credulous coverage of topics ranging from homeopathy to magic crystals to Gwyneth Paltrow's goop empire. The Wallace-Wells piece takes things to another level and goes in a very different but arguably worse direction. Rather than giving bad science a pass, he takes good science and presents it so ineptly has to do it a disservice.

I am not going to delve into that science myself. The topic has been well covered by numerous expert and knowledgeable writers [see here and here]. The best I could offer would be a recap. There are some journalistic points I may hit later and I do want to highlight a minor detail in the article that has slipped past most critics, but which is perfectly representative of the dangerous way Wallace-Wells combines sensationalism with a weak grasp of science.

Other stuff in the hotter air is even scarier, with small increases in pollution capable of shortening life spans by ten years. The warmer the planet gets, the more ozone forms, and by mid-century, Americans will likely suffer a 70 percent increase in unhealthy ozone smog, the National Center for Atmospheric Research has projected. By 2090, as many as 2 billion people globally will be breathing air above the WHO “safe” level; one paper last month showed that, among other effects, a pregnant mother’s exposure to ozone raises the child’s risk of autism (as much as tenfold, combined with other environmental factors). Which does make you think again about the autism epidemic in West Hollywood.

No, David, no it doesn't.

I want to be painstakingly careful at this point. These are complex and extraordinarily important issues and it is essential that we do not lose sight of certain basic facts: by any reasonable standard, man-made climate change is one of the two or three most important issues facing our country; the effect of various pollutants on children's mental and physical development should be a major concern for all of us; high ozone levels are a really bad thing.

But the suggestion that ozone levels are causing an autism epidemic in West Hollywood is both dangerous and scientifically illiterate. You'll notice that I did not say that suggesting ozone levels cause autism is irresponsible. Though the study in question is outside of my field, the hypothesis seems reasonable and I do not see any red flags associated with the research. If Wallace-Wells had stopped before adding that last sentence, he would've been on solid ground, but he didn't.

Autism is frightening, mysterious, tragic. This has caused people, particularly parents facing one of the worst moments imaginable, to clean desperately to any explanation that might make sense of their situation. As a result, autism has become a focal point for bad science, culminating with the rise of the anti-vaccination movement. There is no field where groundless speculation and fear-mongering are less welcome.

So, if ozone and other pollutants may contribute to autism, what's so bad about the West Hollywood claim? For that, you need to do some rudimentary causal reasoning, starting with a quick look at ozone pollution in Southern California.

Here are some pertinent facts from a 2015 LA Times article:

EPA Administrator Gina McCarthy selected a limit of 70 parts per billion, which is more stringent than the 75 parts-per-billion standard adopted in 2008 but short of the 60-ppb endorsed by environmentalists and health advocacy groups including the American Lung Assn. The agency’s science advisors had recommended a limit lower than 70 -- and as low as 60.


About one-third of California residents live in communities with pollution that exceeds federal standards, according to estimates by the state Air Resources Board.

Air quality is worst in inland valleys, where pollution from vehicles and factories cook in sunlight to form ozone, which is blown and trapped against the mountains.

The South Coast air basin, which includes Los Angeles, Orange, Riverside and San Bernardino counties, violated the current 75-ppb ozone standard on 92 days in 2014. The highest ozone levels in the nation are in San Bernardino County, which reported a 2012-2014 average of 102 parts per billion.

Now let's look at some ozone levels around the region. West Hollywood, it should be noted, is not great.

But just over the Hollywood Hills, the situation is even worse.

Go further inland to San Dimas and the level is even higher…

Higher still in Riverside ...

Though still far short of what we find in San Bernardino.

If you look at autism rates by school district and compare them to ozone levels, it is difficult to see much of a relationship. Does this mean that ozone does not contribute to autism? Absolutely not. What it shows is that, as with many developmental and learning disabilities, the wealthy are overdiagnosed while poor are underdiagnosed. It is no coincidence that a place like Santa Monica/Maibu (a notorious anti-vaxxer hotspot) has more than double the diagnosis rate of San Bernardino.

The there's this from the very LA Times article by Alan Zarembo that Wallace-Wells cites [emphasis added]:

 Irva Hertz-Picciotto, an epidemiologist at UC Davis, suspects that environmental triggers such as exposure to chemicals during pregnancy play a role. In a 2009 study, she started with a tantalizing lead — several autism clusters, mostly in Southern California, that her team had identified from disability and birth records.

But the hot spots could not be linked to chemical plants, waste dumps or any other obvious environmental hazards. Instead, the cases were concentrated in places where parents were highly educated and had easy access to treatment.

Peter Bearman, a sociologist at Columbia University, has demonstrated how such social forces are driving autism rates.

Analyzing state data, he identified a 386-square-mile area centered in West Hollywood that consistently produced three times as many autism cases as would be expected from birth rates.

Affluence helped set the area apart. But delving deeper, Bearman detected a more surprising pattern that existed across the state: Rich or poor, children living near somebody with autism were more likely to have the diagnosis themselves.
Living within 250 meters boosted the chances by 42%, compared to living between 500 and 1,000 meters away.

The reason, his analysis suggested, was simple: People talk.
They talk about how to recognize autism, which doctors to see, how to navigate the bureaucracies to secure services. They talk more if they live next door or visit the same parks, or if their children go to the same preschool.

The influence of neighbors alone accounts for 16% of the growth of autism cases in the state developmental system between 2000 and 2005, Bearman estimated.

In other words, autism is not contagious, but the diagnosis is.

No comments:

Post a Comment