Rumors, Experts, and Human Growth Hormone

Posted on April 24, 2007 by


Today’s guest blogger is JC Bradbury. JC is an associate professor at Kennesaw State University. He is well-known for his website – Sabernomics – which combines the best of sabermetrics and economics. And of course, he is The Baseball Economist (which is both his title and the title of his first book).

If you want to have people read something you write, write about performance-enhancing drugs. Earlier this month, wrote a post about how human growth hormone (HGH) does not improve athletic performance. The response I received was overwhelming. Links came from everywhere: message boards, blog posts, and personal e-mails. What was surprising was not that people found the topic interesting, but the number of people who openly continued to believe HGH enhances performance with ZERO evidentiary backing. I have no problem with disagreements, but to choose to believe that HGH has performance-enhancing qualities based on what we know is silly. I’d like to go through some common objections to my post and then offer from general thoughts on deferring to experts.

First, let me briefly summarize why I believe that HGH does not help baseball players.

— Studies that examine the impact of HGH on strength find that patients taking HGH show no improvement over patients who don’t use HGH.

— Every study that I read spends a significant amount of time discussing the high incidence of side effects that are painful and would undoubtedly decrease performance. For example, carpal tunnel and foot pain are frequent occurrences among users. If you are going to focus on the potential performance-enhancing qualities of the drug, you must weigh them against the performance-diminishing consequences as well. As best I can tell, the improvements are non-existent and the damage is very real.

— Theoretically, even without looking at the empirical evidence there are very good reasons to believe that while additional growth hormone increases mass, it does not increase strength. Cell growth is not always a good thing. Take cancer, for example. Cancer is uncontrolled cell growth. The problem with cancer is that the cells don’t do what they are supposed to. Similarly, muscle growth stimulated by HGH doesn’t produce the same type of muscle that improves strength.

— The sum of the evidence is so overwhelming that introductory textbooks in exercise physiology state that HGH is not an ergogenic aid.

Here are a few objections I have read. Now, just because I disagree that these arguments successfully counter the existing evidence does not mean that they are irrelevant. But, given what we know and what scientists are allowed to study, I don’t think they cast doubt on the current consensus. I respond to each individually, and then offer general commentary at the end.

— HGH may not improve strength, but it does improve eyesight.

This is a rumor that probably has its origins in one passage from Game of Shadows. “There was an added benefit to the new drug regimen [which included HGH]: Bonds stopped complaining about his eyes. Although medical experts say there’s no scientific basis to the claim, some growth hormone users have reported improved vision.” (P.75)

Even the text behind the rumor includes the caveat “medical experts say there’s no scientific basis to the claim.” Now, if you are someone who said, “hey, what about it’s effect on eyesight?” That is a perfectly innocent question, but it turns out that there is no reason theoretically to think that this might be true. But I saw several people state that the evidence doesn’t disprove the rumor, and therefore the performance-enhancing assumption is acceptable. I’m not sure how any research can overcome a criticism with no concrete theoretical or empirical backing. No scientist will be able to design the perfect study.

— HGH doesn’t improve strength, but it does improve recovery, allowing players to play better every day.

This is true for steroids. The anabolic effects allow a person’s body to repair faster and therefore bounce back quicker to perform at a higher level. But for HGH, the evidence is that the response is not the same. Muscles do get bigger, but not stronger. The process by which muscles repair themselves is the same thing that makes them bigger and stronger. The evidence is that HGH-induced muscle is not the same as regular muscle, therefore we should not expect a recovery impact.

— The studies of HGH involve elderly men and women, who are not the same as young athletes.

That is true, but the ethical limits we’ve placed on scientific testing do not allow for testing healthy athletes. All we can do is look to studies where testing is allowed in older HGH-deficient adults. Though this information does not come from our ideal sample, it is still very useful. Older human beings are about as physiologically similar to younger humans as we can get. Certainly, these are much better than animal tests, which scientists employ frequently to predict impacts in humans.

Where we have evidence, the evidence is overwhelming that there HGH is not an ergogenic aid. If you are waiting on the perfect study, it’s never going to come. Ethical concerns will prevent scientists from running these tests. We start with the null hypothesis HGH has no effect on athletic performance, and no one has been able to reject this with the studies that exist. All we have to support HGH’s performance-enhancing claims are rumors that an extravagantly expensive drug does something very different from what we observe in carefully controlled scientific experiments. Unsubstantiated rumor or controlled scientific experiments?…I think I’ll go with the latter.

The funny thing about the attention I have received on this subject is that I am not an expert on this subject. I am reporting what other experts have found. And I am shocked that no journalist has investigated this story deeper. I think there is a real lesson to be learned here about relying on experts.

I don’t know much about cars, but I’m glad that other people do. Cars are complicated machines that require special training and knowledge. If it wasn’t for mechanics, I’d have to spend a lot of my time learning about a subject that doesn’t interest me and attempting to diagnose and fix problems that I barely understand. When I start hearing noises under the hood, I don’t get out my tools, I take my car to a mechanic—sometimes several mechanics because I understand that my ignorance makes me a ripe target for fraud. I suspect you do to.

When it comes to performance-enhancing drugs, I rely on what the scientific community has to say. It’s quicker, easier, and I have some confidence that the information I have is correct. Yes, experts do make mistakes, but less so than individuals with no training in the subject. Ultimately, I believe the burden of proof is with those who wish to discredit the scientific consensus.


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