Courtesy Rice University
Rice University student Dale Lloyd II, 19, died from sickle cell complications.
Rice University student Dale Lloyd II, 19, died from sickle cell complications. Courtesy Rice University
In the mid-1970s, after a number of young military recruits died during training, hematologist John Kark was called on by the military to investigate the situation. He initially studied 18 deaths among African-American recruits, 13 of whom were found to have the sickle cell trait.
The most common cause of death was rhabdomyolysis — a condition in which muscle fibers break down and release toxins into the bloodstream. Heatstroke was the next most common cause. The cause of death couldn't be determined in one recruit.
Kark and colleagues analzyed all sudden deaths in recruits. They concluded that black recruits with sickle cell trait had a death rate 30 times higher than black recruits who did not have the trait.
Based on other studies he has done over the past three decades, Kark attributes the sudden death among those with sickle cell trait to what is called heat exertional illness. It's a condition in which heat is the central factor leading to the breakdown of muscle. There are other factors involved, he says, but heat is the principal mechanism that leads to death.
There's debate, however, over whether it's the heat of the environment or the heat produced by muscles themselves that is the main cause. That's because some of the sudden deaths have occurred in moderate climates.
"The problem is that when you work, muscles produce a lot of heat," Kark says. "Eighty percent of the energy goes to heat and the heat is removed by water, by sweating with evaporation in to the air and our lungs and with water and electrolytes lost.
"The blood flow to the muscle and skin increases when you are exercising while the flow to the central organs in the body decreases," he adds. "So you can have oxygen shortage in the gut and the kidney and those two organs can be damaged."
Kark says that when athletes develop heat exertional illness in moderate climates, it might be caused by dehydration, even from the day before. Lack of sleep or alcohol use can also factor in.
He suggests that athletes with sickle cell trait decrease the intensity of exercise, allow for increased periods of rest and increase hydration.
Courtesy Rice University
Dale Lloyd II was on an athletic scholarship to Rice University, the big Division I school in Houston.
Dale Lloyd II was on an athletic scholarship to Rice University, the big Division I school in Houston. Courtesy Rice University
Fifteen athletes, most of them college football players, have died in the past decade from a condition that is benign in most circumstances. They were carrying the sickle cell trait.
Kourtni Livingston, a 14-year-old girl who played basketball for DeSoto High School near Dallas, died running laps outdoors in August 2002. Then University of Missouri linebacker Aaron O'Neal died during a voluntary workout in 2005. Devaughn Darling died shortly after complaining of dizziness and chest pains during off-season conditioning exercises in February 2001 at Florida State University. Experts have found that under conditions such as extreme exertion, high altitudes and hot climate, sickle cell trait is associated with a potentially deadly blood disorder called "sickling."
In January, the National Collegiate Athletic Association is expected to decide whether it will be mandatory for colleges and universities to test athletes for sickle cell trait. But some experts are concerned that this could lead to athletes with the trait being singled out and excluded from sports.
Millions of people in this country have inherited the sickle cell trait, an estimated 1 in 12 African-Americans, but also Hispanics, Mediterranean people, others from parts of the world where malaria is common, and about 1 in 2,000 to 10,000 Caucasians, according to the U.S. Centers for Disease Control and Prevention. Having the sickle cell trait is known to provide some protection against the malaria parasites. This is not the same as having sickle cell anemia, a painful and debilitating disease that affects about 70,000 people in the United States.
In 1998, the federal government began requiring that all infants be screened at birth for the sickle cell trait. Since test results conducted in-hospital may take weeks, that information is seldom passed along to the parents or the child.
Checking for sickle cell trait is not something that ever crossed the mind of Bridgette Lloyd. Her 19-year-old son, Dale Lloyd II, had been an athlete all his life, excelling in football and baseball. He was offered an athletic scholarship to Rice University, the big Division I school in Houston.
"Dale was a gift from God, truly. And I would always instill in him, 'Son, you are truly blessed not only athletically, but academically,' and he would say, 'Mom. You know, you're right.' "
Before he headed off to Rice in June 2006 to prepare for the upcoming fall season, his parents said they had him checked out from top to bottom. More than anything, they wanted to know his heart could withstand the pressure of strenuous workouts.
"We would always look forward to make sure he had a good heart," Lloyd says, "because they always say young people getting out there and working out, sometimes their heart gives out."
In late September, the football team had just returned to campus after a 55-7 bruising. The 190-pound freshman defensive back headed out for an evening with friends. The next day, team members told her, Dale was back on the field for a light workout that included 16 100-yard sprints.
"The light workout turned into a bit more strenuous workout," she says. "They did weightlifting and a lot of running. During the running portion he collapsed."
When she and her husband, Dale Lloyd Jr., arrived at the hospital that afternoon, they were met by doctors who were baffled by his condition.
Bridgette Lloyd says, "They had no idea what they were looking for and what was going on with him. They were trying to get all kinds of information from us. Late into the night someone asked ... if he had the trait."
She means the sickle cell trait. The Lloyds had no idea. It had never occurred to them to have him tested, and no one had suggested that they should. It turned out that Dale Jr. carried the gene and had passed it to his son.
"He passed away the following day," Bridgette Lloyd says.
The cause of death was rhabdomyolysis, a condition associated with sickle cell trait and brought on by extreme exertion, high altitudes and hot climate. The flat red blood cells sickle, stiffen, blocking microvessels that carry the blood, starving tissue of oxygen.
Many coaches and trainers are still ignorant of the problem, says Scott Anderson, director of athletic training at the University of Oklahoma. He became aware of it about 14 years ago when one of his players collapsed. "The physicians at the hospital recognized that he had sickle cell trait, but they said that's not what his problem is," says Anderson.
That athlete survived his collapse, but Anderson wasn't entirely convinced of the doctors' explanation. He undertook an investigation and found that in fact, the athlete's collapse was similar to other cases that had not ended so well.
"Deaths were occurring," Anderson says, and even as athletes were dying those cases were not communicated to the profession as a whole. They were singular cases in isolation and oftentimes individuals would think that it was a unique occurrence."
So Anderson convened a task force of the National Association of Athletic Trainers to study the problem of sickling in young athletes. In 2007, the group released a consensus statement calling for screening of all athletes for sickle cell trait.
"It doesn't matter whether they are playing football or another sport, male athlete or female athlete," Anderson explains. "It doesn't matter whether they are African-American, Caucasian-American, Native American or whatever."
The point is not to exclude anyone from sports, Anderson says, but to make sure that all precautions are taken, with a particular emphasis being placed on educating athletes about their condition. Most of the incidents occur during conditioning training, when these highly competitive athletes are pushing themselves or being pushed to the breaking point. Anderson sets limits.
"We make them aware of signs and symptoms of exertional sickling. If they are experiencing undue fatigue, shortness of breath, a sensation at the lower extremity, a lower back cramping spasm," Anderson says, "we want them to report those symptoms immediately."
At the University of Oklahoma, Anderson says, any athlete would be withdrawn from training at this point to be given time to recover. Rest periods between activities are longer for athletes with the trait than for other players. They may have fewer sprints, for example.
At the same time, trainers make sure that the athlete's capacity to be competitive is not compromised. In fact, in surveys done by the National Football League, it's estimated that 7 percent of the players have the sickle cell trait. Anderson proudly notes that that has included some of Oklahoma's best.
"Curtis Lofton is one. He was an All-American linebacker for us at the University of Oklahoma. He currently plays for the Atlanta Falcons. He's a defensive standout for them."
Unfortunately, Bridgette Lloyd did not know any of this when she sent her son off to Rice University, but she says the NCAA knew about the deaths of young athletes associated with having the sickle cell trait, and so her family sued.
"I found out when Dale passed away, that you will find names and names and names of kids," Lloyd says. "Young people who should have had young and productive lives that were cut short because the NCAA didn't inform them that this situation could affect their health."
As part of a settlement the NCAA agreed to recommend that all universities and colleges offer athletes screening for the sickle cell trait. And Rice University will propose a bylaw at the association's annual meeting to make that mandatory. Currently, 64 percent of colleges screen for the sickle cell trait.
But some African-Americans and sickle cell experts, such as Dr. Elliot Vichinsky, a hematologist at the Children's Hospital Oakland, worry that the mandatory testing policy hasn't been given enough thought.
In the past, African-Americans were blocked from military service and certain kinds of employment if they had the sickle cell trait.
"Given that history," Vichinsky says, "if you just have a willy-nilly 'go get tested and then go see somebody for counseling' [policy], there is a tremendous medical, legal pressure on them to do this. There is inherently a medical-legal risk." He argues that coaches will say to themselves, "Why would I put a trait person out to play on Sunday when it's really hot? I may be liable."