Association Is Not Causation

The  Court of Justice of the European Union’s Dubious Decision

CBS News reported on June 21, 2017, “The highest court of the European Union ruled Wednesday that courts can consider whether a vaccination led to someone developing an illness even when there is no scientific proof.”

According to CNN, this ruling means “if the development of a disease is timely to the person’s receiving a vaccine, if the person was previously healthy with a lack of history of the disease in their family and if a significant number of disease cases are reported among people receiving a certain vaccine, this may serve as enough proof.”

Why the Verdict Matters

That decision is a particularly alarming development given the fact that failure to vaccinate against preventable diseases, such as measles, can lead to death. A 1998 study by former doctor Andrew Wakefield unfortunately linked the MMR (measles, mumps, and rubella) vaccine with autism. That study was later debunked as an “elaborate hoax,” but not before many parents were convinced that the risk of vaccinating their children outweighed any potential benefits. As a result, we saw an outbreak of measles in Minnesota this year among unvaccinated children.

The unbelievable action of the Court of Justice of the European Union (EU) is a symptom of what appears to be a universal oversimplification of complex problems. We are living in an era when, for many people, science is not evidence and fake news is an accepted reality. This has always been true in politics, but now it also has bled into medicine.

Worse, while our legal system seems to include at least some people who know better, and who are still able to separate fiction from reality, evidence from conjecture, and truth from fallacy, that may not consistently be the case in the healthcare community. Instead, truth appears to be relative and negotiable.

The EU high court case involved a Frenchman known as Mr. J.W. who was immunized against hepatitis B in late 1998-99. About a year later, Mr. J.W. was diagnosed with multiple sclerosis. His family blamed vaccine-maker Sanofi Pasteur for Mr. J.W.’s 2011 death. EU’s Court of Justice agreed.

Correlation Does Not Equal Causation

Dr. Paul Offit, a pediatrician and vaccines expert at the University of Pennsylvania, said the criteria used by the court made no sense. “Using those criteria, you could reasonably make the case that someone should be compensated for developing leukemia after eating a peanut butter sandwich,” he said.

I am reminded of a similar irrational thought process underlying the assertion that children with larger shoe sizes have higher intelligence. Carnegie Mellon published a fictional study to illustrate the concept of drawing false conclusions based on spurious associations. In this case, the “study” showed with absolute certainty that children with larger shoe sizes have higher intelligence, forgetting that children’s feet grow, and so does their IQ, along with their problem-solving skills. Of course, a 4th grader has a bigger foot than a 2nd grader, and also has acquired more experience and knowledge to add to his or her overall intelligence.

Of Vaccines and Opioids

Maybe this cognitive dissonance — there’s no scientific proof, but we draw conclusions and act accordingly — contributes to the murky narrative about opioids. The CDC provides statistics about opioids and overdoses that are far too general, and can be ambiguous, obfuscating, or misleading.

For example, overdoses from illicit opioids imported from China and Mexico are pooled with those of prescription opioids. Drawing conclusions from incomplete or inaccurate data like this can place people in pain who need opioids in jeopardy.

The narrative is that the heroin epidemic is due to prescription opioids, because most people who use heroin had a prior exposure to prescription opioids. This may be true just as it is true that children with larger feet have higher IQs, but that does not mean there is a causal relationship.

The problem with the logic that blames the heroin epidemic on prescription opioids is that the same people who had used prescription opioids had previously been exposed to bread, cologne, and water, too. No one is blaming any of those other items for causing people to use heroin.

Exposure to prescription opioids is likely not the major reason people choose to use heroin, either. The reality is that most people using heroin had experience with illegal substances before being exposed to prescription opioids. Using one illicit drug to “get high” and then moving on to using another, perhaps more powerful, illegal drug to get the same effect is a sad progression of a disease in a subset of the population.

A judge on the Court of Justice of the European Union and a policymaker in the United States face similar challenges. They must not use associations of facts as evidence of causality. And, most of all, they must care more about acting from a position of truth and knowledge than they do about giving the public oversimplified solutions to highly complex problems.


  1. Tom Rector on July 3, 2017 at 6:22 pm

    Mass employment drug testing for THC exploded recreational pill use resulting in millions of addicts and thousands of fatal overdose deaths. U.S. workers figured out that they could get away with recreational pill use at or after work especially if they could get a prescription for opiates.

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