In The Politics of Autism, I analyze the discredited notion that vaccines cause autism. This bogus idea can hurt people by allowing diseases to spread. And among those diseases could be COVID-19.
And among the many peddlers of "alternative medicine" is Joseph Mercola.
According to the U.S. Centers for Disease Control and Prevention,” Mercola wrote, “the dramatic uptick [in autism] is in part due to improved and more comprehensive identification and diagnosis. However, improved diagnosis alone cannot explain this trend … No, something is going on.”
It's not clear why something has to be “going on.” Well-designed studies published over the last decade or so have shown that broadening the diagnosis to autism spectrum disorder (ASD) to account for a wider variety of symptoms explains the increase in cases.
For example, many people in the 1980s diagnosed with a developmental language disorder, up to 25 percent in one paper, would be “diagnosed unambiguously with autistic disorder” today. More extensive screening, broader public awareness, and expanded health care access have had a similar effect by uncovering previously undiagnosed cases. If this hypothesis is correct, there's been no unexplained increase in autism.
A variety of environmental exposures may contribute to autism, but this doesn't help Mercola's case. For one thing, some of the factors he wants to blame, like vaccination, aren't linked to ASD risk. “Current evidence suggests that several environmental factors including vaccination, maternal smoking, thimerosal exposure, and most likely assisted reproductive technologies are unrelated to risk of ASD,” a 2017 meta-analysis noted. More importantly, the evidence for environmental contributions to autism is still limited, the authors of a 2019 review concluded:Our understanding of autism etiology could be advanced by research aimed at disentangling the causal and non-causal environmental effects, both founding and moderating, and gene-environment interplay using twin studies, longitudinal and experimental designs. The specificity of many environmental risks for ASD remains unknown and control of multiple confounders has been limited.Taken together, this research suggests a less scandalous conclusion than Mercola's: there hasn't been a genuine increase in ASD, and we have much to learn about the possible environmental causes in cases that have been diagnosed.
