When the National Basketball Association (NBA) preseason opens next weekend, one notable player won’t be there.
Chris Bosh, the 11-time All-Star and 2-time world champion with the Miami Heat, missed the past season and a half due to the team’s concerns over recurring blood clots.
In July, Bosh officially called it quits, the blood clots bringing an end to a likely Hall of Fame career.
Bosh, 33, is 6-foot-11. While not all tall people face the prospect of blood clots, that height may have increased his risk for developing them.
Men taller than 6-foot-2 face a 65 percent higher risk of developing clots than men shorter than 5-foot-3, according to a study published this month.
Researchers also found a similar increased risk in women.
What the research uncovered
The researchers, whose findings were published in the journal Circulation: Cardiovascular Genetics, examined a database that followed the health outcomes of 2 million Swedes.
The researchers searched for pairs of siblings who are, as they put it, “discordant for height.”
The taller siblings were significantly more likely than their shorter brothers or sisters to developing venous thromboembolism, a blood clot starting in a vein.
The clots can start in a deep vein, normally in a leg (deep vein thrombosis).
They can then break off and travel to the lungs, where they may block blood supply (pulmonary embolism).
The researchers found an association between height and both types of clots in men. In women, only deep vein thrombosis risk increased with height.
A common, serious ailment
Bosh reportedly has had both types at different times. These types of recurrences are not uncommon.
Blood clots are the third most common cause of heart attacks and strokes, according to the American Heart Association.
The organization says the clots affect up to 600,000 people in the United States each year.
The Vascular Disease Foundation has found that 100,000 to 180,000 Americans die every year — or about 300 to 500 every day — from a pulmonary embolism. Women are particularly at risk.
But fewer than 1 in 4 people recognize the signs of a blood clot, according to the National Blood Clot Alliance.
The group says those symptoms can include, in the case of deep vein thrombosis, swelling, pain or tenderness akin to that from a charley horse, discoloration of the skin, and skin that’s warm to the touch.
In the case of a pulmonary embolism, symptoms may include sudden shortness of breath, stabbing pain in the chest (particularly with deep breaths), rapid heart rate, and coughs (particularly with bloody mucus).
Athletes may face particularly high risk of clots due to sitting for long periods of time on frequent flights or bus rides between games as well as dehydration, hard contact to the legs, and surgeries to repair injuries.
African-Americans, like Bosh, are also at greater risk — 30 to 60 percent greater, according a 2016 study — than other ethnicities.
Other factors that can increase risk for athletes and nonathletes alike include cancer, obesity, pregnancy, hormone-based birth control methods, and family history.
Height as a risk
The lead researcher of the new study, Dr. Bengt Zöller of Malmö University Hospital in Sweden, said in a statement that height should now be added to that factor list and included in risk assessments.
He speculated that the simple fact that taller people have longer veins and their blood has farther to travel may play a role in explaining the increased risk his team found.
“It could just be that because taller individuals have longer leg veins there is more surface area where problems can occur,” he said. “There is also more gravitational pressure in leg veins of taller persons that can increase the risk of blood flow slowing or temporarily stopping.”
The best way for taller people to reduce their risks may be to avoid the other risk factors — ones they can control — as much as possible.
“We have no control over our height, but we certainly can all take the appropriate measures in making healthy lifestyle choices to reduce the risk of various conditions,” Zöller said.
Bosh, now a spokesperson for the blood thinner Xarelto, found out about a blood clot in his leg while at the All-Star Game festivities in 2016.
He spent the next six days in a hospital in Toronto.
“And then came not being able to play the game I love, the game that I’ve spent a lifetime working to master and evolve with and find success in,” he wrote in a goodbye letter to Miami fans in July.
The Heat kept Bosh off the court — over his objections — over concerns that due to his blood thinners a blow to the head or other hard contact could be debilitating or deadly.
He hasn’t played since that All-Star weekend last year.