'Sticky' Blood May Underlie Development Of Early Atherosclerosis In Men

April 20, 1998

DALLAS, April 21 -- The stickier, or more viscous, a man's blood is, the greater his risk of developing the kind of blood vessel damage that can eventually lead to a heart attack or stroke, a study published in today's Circulation: Journal of the American Heart Association reports.

The increased risk does not hold true for women -- which may shed light on why males tend to develop heart disease and suffer strokes at a younger age than females, says lead author Amanda J. Lee, Ph.D., research statistician at the University of Edinburgh Medical School, Scotland.

The study is the first to link blood stickiness to the early development of atherosclerosis, which results from the build-up of cholesterol, fats and biological debris in the tissue lining the inside of blood vessels. This build-up can obstruct blood flow to the heart and brain and thereby cause a heart attack or stroke.

The researchers cannot explain the lack of correlation between blood viscosity and blood vessel-wall thickening in women. They do, however, have several hypotheses.

A number of risk factors contribute to the development of atherosclerosis, and an interaction may be required among these risk factors to cause the blood vessel damage that occurs in men. One interaction may involve cigarette smoking, which is greater in men than women. A more likely explanation, however, is that blood viscosity has a different effect in men than women, which accounts for its role in early blood vessel damage, Lee says.

Blood viscosity may act differently in the two sexes because of differences in speed of the blood as it courses through vessels and subtle differences between the two sexes in the geometry, or shape, of blood vessels, she says. A higher blood velocity in men, coupled with greater viscosity, cigarette smoking and blood pressure, may create greater sheer stress that does more damage in men than in women to the one-cell-thick inner lining of blood vessel walls.

This may preferentially predispose men to the buildup of deposits in the blood vessel walls that can eventually lead to heart attacks and strokes, Lee suggests. "Therefore, it may be that viscosity may explain why men have higher heart attack and strokes rates than women."

Previous studies identified blood viscosity and elevated levels of certain blood substances, including the protein fibrinogen, as increasing the risk of a heart attack or stroke caused by atherosclerotic disease. Other studies have shown that an increased thickness of the intima and the media, the two layers within the blood vessel wall where deposits form, can indicate early atherosclerosis.

"But nobody before us looked at the stickiness of blood and its various determinants to see whether they may have an effect on intima-media," she says.

Moreover, when the researchers statistically adjusted their findings to account for the role of cholesterol, age, blood pressure and cigarette smoking in blood vessel thickening, they found that sticky blood still increased the intima-media thickening risk in males.

"We've shown that these effects are independent of the known common risk factors, and so basically, we can say that viscosity has an effect on early atherosclerosis in men," Lee says.

She and her colleagues used data from the Edinburgh Artery Study, a prospective study of 1,592 men and women 55 to 74 years old when they were enrolled in the late 1980s. At the time of entry, each answered a risk-assessment questionnaire and gave blood. Five years later, as part of their follow-up, the volunteers were given a B-mode ultrasound scan, which can provide a image of the thickness of the intima and media layers in the blood vessels to the brain.

This ultrasound technique yields a black-and-white longitudinal image of a vessel from which thickness measurements can be made. "We're talking very small thicknesses-millimeters or parts of millimeters thick," Lee says. (One millimeter equals 0.0394 inch.).

The researchers compared the intima-media thickness measurements of 1,106 study participants with their blood-flow status and the levels of various substances in their blood. These included blood and plasma viscosity; packed red cell volume (hematocrit); fibrinogen, a protein involved in clotting; von Willebrand factor, which can indicate damage to cells lining the vessel; tissue plasminogen activator, an anticlotting factor; and fibrin D-dimer, an indicator of fibrinogen activity.

The study noted significant correlations in men -- but not in women -- between intima-media thickness and elevated blood viscosity and three major elements that determine blood stickiness: plasma viscosity, fibrinogen, and the red-blood-cell count.

Co-authors of the paper are Philip I. Mowbray, B.Sc.; Gordon D.O. Lowe, F.R.C.P.; Ann Rumley, Ph.D.; F. Gerald R. Fowkes, F.R.C.P.E.; and Paul L. Allan, F.R.C.R. The study was funded by the British Heart Foundation.
-end-
Media advisory: : Dr. Lee can be contacted by phone 011-44-131-650-3216. (Please do not publish telephone numbers.)



American Heart Association

Related Blood Pressure Articles from Brightsurf:

Children who take steroids at increased risk for diabetes, high blood pressure, blood clots
Children who take oral steroids to treat asthma or autoimmune diseases have an increased risk of diabetes, high blood pressure, and blood clots, according to Rutgers researchers.

High blood pressure treatment linked to less risk for drop in blood pressure upon standing
Treatment to lower blood pressure did not increase and may decrease the risk of extreme drops in blood pressure upon standing from a sitting position.

Changes in blood pressure control over 2 decades among US adults with high blood pressure
National survey data were used to examine how blood pressure control changed overall among U.S. adults with high blood pressure between 1999-2000 and 2017-2018 and by age, race, insurance type and access to health care.

Transient increase in blood pressure promotes some blood vessel growth
Blood vessels are the body's transportation system, carrying oxygen and nutrients to cells and whisking away waste.

Effect of reducing blood pressure medications on blood pressure control in older adults
Whether the amount of blood pressure medications taken by older adults could be reduced safely and without a significant change in short-term blood pressure control was the objective of this randomized clinical trial that included 534 adults 80 and older.

Brain blood flow sensor discovery could aid treatments for high blood pressure & dementia
A study led by researchers at UCL has discovered the mechanism that allows the brain to monitor its own blood supply, a finding in rats which may help to find new treatments for human conditions including hypertension (high blood pressure) and dementia.

Here's something that will raise your blood pressure
The apelin receptor (APJ) has been presumed to play an important role in the contraction of blood vessels involved in blood pressure regulation.

New strategy for treating high blood pressure
The key to treating blood pressure might lie in people who are 'resistant' to developing high blood pressure even when they eat high salt diets, shows new research published today in Experimental Physiology.

Arm cuff blood pressure measurements may fall short for predicting heart disease risk in some people with resistant high blood pressure
A measurement of central blood pressure in people with difficult-to-treat high blood pressure could help reduce risk of heart disease better than traditional arm cuff readings for some patients, according to preliminary research presented at the American Heart Association's Hypertension 2019 Scientific Sessions.

Heating pads may lower blood pressure in people with high blood pressure when lying down
In people with supine hypertension due to autonomic failure, a condition that increases blood pressure when lying down, overnight heat therapy significantly decreased systolic blood pressure compared to a placebo.

Read More: Blood Pressure News and Blood Pressure Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.