Being tall and obese may increase your risk for potentially dangerous blood clots, according to research in Arteriosclerosis, Thrombosis, and Vascular Biology: Journal of the American Heart Association.
Obesity is a well-known risk factor for clots in deep veins (usually in the legs) and for pulmonary embolism, a clot in blood vessels of the lungs that can result in sudden death or strain on the heart. Together, the two conditions are called venous thromboembolism (VTE).
Compared with short (5 feet, 7.7 inches or less) and normal-weight men (body mass index < 25kg/m2), the age-adjusted risk of VTE was:
- 5.28 times higher in obese and tall men
- 2.57 times higher in normal-weight and tall men (at least 5 feet, 11.7 inches tall)
- 2.11 times higher in obese and short men
The amount of risk conferred by being both obese and tall was comparable to other known risk factors for VTE, including pregnancy, the use of oral contraceptives, and carrying one gene for an inherited predisposition to clotting called Factor V Leiden.
Compared with short (5 feet, 2.6 inches or less) normal-weight women, the age-adjusted risk of VTE was:
- 2.77 times higher in obese and tall women
- 1.83 times higher in obese and short women
- Not increased in normal-weight and tall women (more than 5 feet, 6 inches)
“We believe that we observed the increased risk in tall and normal-weight men, but not women, because most women do not get sufficiently tall,” said Sigrid K. Braekkan, Ph.D., senior study author and a researcher in the Hematological Research Group at the University of Tromso in Norway. “The risk may be present in very tall women, but there were too few to investigate this properly.”
Researchers said more studies are needed to determine the mechanisms of the association between tall stature, excess weight, and the combination of the risk of VTEs. “In tall people, the blood must be pumped a longer distance by the calf-muscle pump, which may cause reduced flow in the legs and thereby raise the risk of clotting,” Braekkan said.
The researchers previously found a strikingly similar rise in clot risk along with height in American men, and believe that the height cut-offs would apply to Caucasian populations in other regions.
In the United States, more than 275,000 people each year are hospitalized with deep vein clots or pulmonary embolism, according to the American Heart Association.