Sickle Cell on the Football Field

red-blood-cells

A sickle cell (left) and a normal red blood cell (right). From carnegiescience.edu.

In 2006, Rice University football player Dale Lloyd II collapsed during a practice and later died. The cause of death was acute exertional rhabdomyolysis, a sudden breakdown of muscle tissue into the blood brought on by strenuous exercise. But the trigger for Lloyd’s death may have been sickle cell trait, the name for when a person carries one of the two genes required for full-blown sickle cell disease.

People with sickle cell disease form abnormal red blood cells that can lead to chronic pain, hypertension, stroke, and death, while people with sickle cell trait (approximately 2 million in the U.S.) are generally thought to be symptom-free. But Lloyd’s death drew attention to potentially fatal consequences for athletes with sickle cell trait, and a lawsuit filed by the player’s family led to the NCAA mandating testing for all Division I athletes in 2010.

But is screening for sickle cell trait the best preventive measure for college athletes? That was the topic on the table at the first Department of Pediatrics Grand Rounds of 2011 last week, where both the medical and ethical implications of the NCAA’s new policy were considered. Though mandatory sickle cell trait screening has previously been adopted by the military and the National Football League, the NCAA stance could cause a “trickle-down” effect to high schools and youth sports, leading to millions of tests that might cause more harm and expense than good.

At least fifteen NCAA athletes have died from sickle cell trait-related causes in the last 30 years. But given that there have been approximately 2 million total athletes over that time span, that’s only 1 death for every 400,000 people, said Holly Benjamin, associate professor of pediatrics and surgery. Compared to more common, harmful occurrences such as concussions and spinal cord injuries, that’s an exceedingly rare event.

Which is not to say that it shouldn’t be closely monitored. Sickling, the name for a sickle-cell-related attack, can develop after as little as 2 or 3 minutes of strenuous exercise, and can be exacerbated by heat, altitude, and dehydration, Benjamin said. Parents, coaches, and trainers should be vigilant about athletes who suddenly collapse, giving them fluids and oxygen and transporting them to the nearest emergency department.

But while screening athletes for sickle cell trait might improve the response to an athlete’s collapse, preventing that collapse in the first place would be even more beneficial. As a demonstration, Lainie Ross, professor of pediatrics, surgery, and medicine, used the history of sickle cell trait testing in the American military, which has faced similar tragedies and pressure to screen.

After 4 sickle cell trait-related deaths in 1970, a study found that African-American recruits with the gene were 30 times more likely to die during basic training. In response, the Armed Forces considered screening for carriers of the gene and restricting service in those with positive tests. Meanwhile, another study was started to test whether the danger could be reduced by using the wet-bulb globe temperature (WBGT) index, a measure incorporating temperature, humidity and other factors to determine how dangerous conditions are for physical activity. An intervention based around reducing exertion and increasing rest for basic training recruits on days with a high WGBT index was successful not only in completely eliminating deaths related to sickle cell trait, but reduced deaths in non-carriers as well.

“What this shows is that effective intervention does not require the identification of sickle cell trait,” Ross said.

If an organization still decides to screen, it’s important to test everyone, Ross said. Though sickle cell trait and disease are most common in African-Americans, people from other ethnic backgrounds may also carry the genes and should be tested. And while most of the deaths related to sickle cell trait have occurred in football players, morbidities and mortalities have also been reported in distance running, basketball, and swimming, Ross said. Yet the new NCAA policy earned mixed reviews in the end from Ross because it limits screening only to the top-flight athletes.

“It may be that no sports are safe, so the NCAA policy requiring testing in all athletes makes sense,” Ross said. “But in some ways you would argue Division II and III players are at greater risk because they may be less likely to do year-round conditioning.”

However, testing the roughly 400,000 athletes across all three divisions would be very costly for the NCAA, which has already chosen a cheaper, less reliable test (called Sickledex) for its Division I screening. Those costs might be avoidable if more athletes were aware of sickle cell screening tests that were likely performed when they were newborns, Benjamin and Ross said, but the results of those tests are not always successfully communicated to parent and child. Improving that process, educating carriers of sickle cell genes, and continuing to research the risks associated with sickle cell trait are all important initiatives to prevent athletic deaths (a recent grant from the Greenwall Foundation will fund Ross’ research on how to apply the military’s experience to athletes). But  in the meantime, the speakers advised that colleges looking to protect their athletes should take a harder look at training, not testing.

“Through modified training, we can reduce the deaths of everyone from exercise-related health illness.” Ross said.

About Rob Mitchum (526 Articles)

Rob Mitchum is communications manager at the Computation Institute, a joint initiative between The University of Chicago and Argonne National Laboratory.

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