Where You Put on Pounds May Influence Clot Risk - Big hips in women,
wide waists in men spell trouble, study finds

http://www.nlm.nih.gov/medlineplus/news/fullstory_91068.html

Monday, October 26, 2009

MONDAY, Oct. 26 (HealthDay News) -- The location of excess body fat
appears to affect the risk of dangerous blood clots in veins, although
that location differs in men and women, a new Danish study indicates.

The 10-year study found that bigger hips are associated with an
increased risk of venous thromboembolism (VTE) in women but not men,
while a wider waistline was associated with increased risk in men,
according to a report published online Oct. 26 in the journal
Circulation.

Obesity in general is an established risk factor for VTE, which occurs
when a blood clot blocks a vein. When VTE happens in a leg, it is
known as deep vein thrombosis. In a lung, it is a pulmonary embolism.
A particularly deadly form of VTE, thromboembolism, occurs when a clot
travels from a leg to a lung.

Researchers at Aarhus University Hospital followed more than 57,000
Danish men and women, aged 50 to 64 when the study started, assessing
the relationships between body mass, fat distribution and VTE. The
initial analysis showed that waist circumference was associated with
VTE risk in both men and women.

"When hip circumference was adjusted for waist circumference, the
association between hip circumference and VTE was eliminated for men
but was still significant for women," the report said. "In contrast,
when waist circumference was adjusted for hip circumference, the
association between waist circumference and VTE was eliminated for
women but was still significant for men."

"Further studies are needed to explain the associations," they wrote.

The Danish study results echoes those of an American study reported
earlier this year, said Lyn Steffen, an associate professor of
epidemiology at the University of Minnesota School of Public Health,
and a leader of that study.

The Minnesota group followed more than 20,000 people for more than 12
years and found an association between VTE risk and metabolic
syndrome, a constellation of risk factors including obesity, high
blood pressure, insulin resistance and high blood cholesterol. A
heightened risk of VTE was attributed to obesity.

"The message here is that obesity is a risk factor for venous
thrombosis," Steffen said. "The effect of obesity in women might be
the same as in men, but just is not measured in waist circumference."

It's possible that obesity increases the likelihood of developing
blood clots, and it also might have a negative effect on the
endothelium, the delicate lining of blood vessels, Steffen said.

"There is information that obesity contributes to inflammation, and it
is associated with the metabolic syndrome, which predisposes to
stroke," said Dr. Amytis Towfighi, an assistant professor of clinical
neurology at the University of Southern California. "There may be
similar effects in thrombotic disease, as well as mechanisms that are
not well understood at this point."

SOURCES: Lyn Steffen, Ph.D, associate professor, epidemiology,
University of Minnesota School of Public Health, Minneapolis; Amytis
Towfighi, M.D., assistant professor, clinical neurology, University of
Southern California, Los Angeles; Oct. 26, 2009, Circulation, online