Is thyroid replacement a performance-enhancing drug?

Has one physician uncovered the secret to Olympic Gold medals? And is that secret as simple as undiagnosed low thyroid function? That’s the question posed in a recent Wall Street Journal column entitled U.S. Track’s Unconventional Physician. Like the story that Steven Novella described yesterday, this narrative describes the medical practice of Dr. Jeffrey S. Brown, who sees thyroid illness where others see normal thyroid function. He has his critics, but his high-profile athlete patients have won a collective 15 Olympic gold medals. Case closed & Q.E.D.? Not quite. The WSJ actually does a pretty good job questioning the validity of Brown’s claims, which are far removed from the current medical consensus:

In athletic circles, Brown is a medical hero. He’s a paid medical consultant to Nike. The most renowned running coach at Nike, Alberto Salazar, calls Brown the best sports endocrinologist in the world. And athletes in growing numbers are coming to share Brown’s belief that heavy training can suppress the body’s production of the thyroid hormone, leaving them too exhausted to perform at peak. On the wall of the medical office of Jeffrey S. Brown is a photograph of Carl Lewis, the nine-time Olympic gold medalist. Lewis is one of several former or current patients of Brown’s who have climbed the Olympic podium, including Galen Rupp, who won a silver medal in the 10,000 meters at the London Olympics. “The patients I’ve treated have won 15 Olympic gold medals,” said Brown. Among endocrinologists, Brown stands almost alone in believing that endurance athletics can induce early onset of a hormonal imbalance called hypothyroidism, the condition with which he diagnosed Lewis and Rupp. Brown said he knows of no other endocrinologists treating athletes for hypothyroidism, a fatigue-causing condition that typically strikes women middle-aged or older. Several endocrinology leaders had never heard of hypothyroidism striking young athletes.

Now when I read “unconventional” and “stands alone” my skeptical alarm starts ringing. There is no shortage of debate about thyroid disease, ranging from the utter nonsense offered by “alternative health” practitioners to valid scientific discussions about the thresholds where normal function is considered abnormal and subject to treatment. Brown is an endocrinologist, however, and he’s treating elite athletes who are pushing their physical conditioning far beyond that seen by most medical doctors and almost all endocrinologists. So what’s the basis of the concern? The WSJ story goes on to discuss two different issues: What the proper threshold is for thyroid disease, and whether thyroid replacement is performance enhancing.  Let’s take each of these in turn. I’ve covered thyroid diseases and its related pseudoscience before, and a summary of the standard approach is necessary before we look at the some of the broader questions that have emerged from the story. All I know about these patients is what the WSJ is describing, so for the sake of brevity I’m going to focus on the types of cases that Dr. Brown appears to be identifying and ignore other causes of thyroid disease, which would require different treatment approaches.

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