Washington: You are more likely to develop blood clots if you are tall, obese and male, according to a new study.
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).
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.
"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, senior study author and a researcher in the Hematological Research Group at the University of Tromsø in Norway.
"The risk may be present in very tall women, but there were too few to investigate this properly," added Braekkan.
"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," said Braekkan.
"Understanding and preventing VTE is important because even the first occurrence may be fatal. Obesity, in combination with other VTE risk factors, has been shown to substantially increase the risk, so we wanted to assess the combined effects of tall stature and obesity," he added.
The study has been published in the Arteriosclerosis, Thrombosis and Vascular Biology: Journal of the American Heart Association.