Being Tall, Obese May Boost Risk of Blood Clots
Risk Highest for Men, but Researchers Don't Know Why Height Plays a Role
Behind the Link
Exactly why the link between height, obesity, and blood clots occurs is not known, Braekkan says. In taller people, the blood must be pumped a longer distance. That may cause reduced blood flow in the legs and raise clot risk.
Obesity is linked with constant low-grade inflammation, and that may make blood more prone to clot, the researchers speculate.
''It may be that tall people have more venous valves," Braekkan says. "Venous clots often originate in the area around a venous valve pocket. Height is to a high degree genetically determined. Though it seems unlikely, it cannot be ruled out that height and unrecognized venous clot risk factors have shared genetics."
Advice for Tall, Obese Men and Women
''The most important [advice] is to stay slim or lose weight when obese," Braekkan says. Doctors should take into account body height and weight when considering a patient's risk for blood clots, Braekkan says.
Ravi Dave, MD, a staff cardiologist at Santa Monica-UCLA Medical Center & Orthopaedic Hospital in Santa Monica, Calif., agrees. A tall, obese person should take extra precautions to avoid blood clots, he tells WebMD. That is especially true, he says, if they are in situations that raise the risk, such as taking a long airplane flight.
"Wear loose clothing, try for an aisle seat, get up and walk around," he says. Smoking also increases the risk, he says.
He reviewed the study findings for WebMD. The risk found for tall, obese men of more than five times, he says, is ''pretty dramatic."
Although the study does not prove cause and effect -- only a link -- the statistics are strong, says Roy Silverstein, MD, chair of cell biology and a hematologist at Cleveland Clinic's Taussig Cancer Institute. He also reviewed the study findings for WebMD.
One take-home message, he says, is to lose weight if you are obese, tall or short. "I think it would be a mistake to think if you are short you don't have to worry about obesity [and blood clot risk]," he says.