Postmenopausal Heart, Stroke Risk Best Determined Before the Change

FOR RELEASE: 4 p.m. EDT, ThursdayMay 3, 2001

CONTACT: For journal copies only,please call: (214) 706-1396For other information, call:Carole Bullock: (214) 706-1279 [email protected]Bridgette McNeill: (214) 706-1135

American Heart Association journal report:Postmenopausal heart, stroke risk best determined before "the change"

DALLAS, May 4 -- A woman's cardiovascular risk factors such as cholesterol and blood pressure readings before menopause are a more accurate predictor of whether she will develop heart disease or stroke after menopause, researchers report in the May issue of Stroke: Journal of the American Heart Association.

"The premenopausal risk factors may be a stronger predictor of carotid atherosclerosis because they represent cumulative risk factor exposure during the premenopausal years whereas the risk factor changes during the early postmenopausal years have a shorter time for influence," says Karen A. Matthews, Ph.D., professor of psychiatry and epidemiology at the University of Pittsburgh Medical Center and lead author of the study.

This means that women who are at high risk for strokes and heart attacks after menopause can be identified during the years before menopause. "Prevention strategies should not be put off until menopause when a women's risk of cardiovascular disease increases dramatically," says Matthews.

The study was designed to describe changes in cardiovascular risk factors shortly before menopause and up to five years after menopause. A second goal was to evaluate the association between risk factors before and after menopause and carotid atherosclerosis.

The researchers evaluated 372 women (339 of whom were white) who completed examinations before menopause and again at one and five years after cessation of their menstrual cycles. Their average age was 47.5 at premenopause examinations in 1983 and 1984. The exams included measurements of cholesterol, blood pressure, glucose, body weight, and body mass index (BMI, which is weight in proportion to height). Beginning in 1993, the postmenopausal exam included evaluation of the carotid arteries to determine whether thickening had occurred by ultrasound imaging -- 314 of the 372 women had ultrasound studies.

During the time from perimenopausal (the few years immediately preceding menopause) to first-year postmenopausal examination the changes in LDL, triglycerides and body mass index were larger than those between the first and fifth year after menopause. LDL increased .47 mmol/L (17.7 mg/dl) in perimenopause compared to an .06 mmol/L (2.5 mg/dl) increase after menopause; the triglyceride change was .23 mmol/L (20.5 mg/dl) and .11 mmol/L (9.3 mg/dl), respectively.

Premenopausal risk factors were a stronger predictor of the amount of carotid thickening and plaque revealed by ultrasound.

"Women who had elevated cholesterol, higher blood pressures and increased body weight before menopause had increased blood vessel thickening and atherosclerotic plaque formation in the neck arteries after menopause. Such changes in the carotid arteries are associated with an increased heart attack and stroke risk," says Matthews.

None of the changes in risk factors during the early postmenopause period were associated with plaque formation.

The risk of heart disease and stroke increases after menopause in part because estrogen production decreases. Doctors often step up efforts to encourage postmenopausal women to adopt habits and treatments that may ward off heart disease and stroke. However, the new study suggests taking preventive steps earlier because it finds that many women already have risk factors -- elevated levels LDL and triglycerides -- as they approach menopause. More importantly, these premenopausal risk factors, even if they are within normal range, were more strongly related to the development of blockages in the blood vessels than risk factors measured at or after menopause.

"At least five years after menopause a substantial number of women had measurable plaque," says Matthews. "Women with elevated plaque had risk factors for cardiovascular disease when they were premenopausal, including elevated systolic blood pressure, LDL cholesterol and low levels of the good HDL cholesterol.

"This suggests that we can look relatively early, before the onset of symptoms, to see who is at high risk. Prevention efforts should begin when a women is in her 40s or even younger, so we don't have to deal with lots and lots of people who are very ill later in life."

An accompanying editorial by Gretchen E. Tietjen, M.D. and Robin Brey, M.D. says the study highlights the importance of reestablishing normal ranges of blood pressure and lipids for premenopausal women and of investigating cholesterol-lowering statin drugs and aggressive blood pressure control as a means of preventing a stroke in postmenopausal women.

"Those risk factors don't necessarily have to be abnormal to increase the risk," says Tietjen, associate professor and chair of neurology at the Medical College of Ohio in Toledo. "Maybe we ought to be setting the bar a little lower for what we determine to be abnormal."

The study did not directly address the impact of hormone replacement therapy on cardiovascular risk factors. That impact could be assessed in future evaluations to determine whether altering risk factors with hormone replacement therapy or other interventions translates into less atherosclerotic disease, they write.

Co-authors were Lewis H. Kuller, M.D., DrPH; Kim Sutton-Tyrrell, DrPH; and Yue-Fang Chang, Ph.D.

The work was funded in part by the National Institutes of Health.

###NR01-1282 (Stroke/Matthews)

Media Advisory: Dr. Matthews can be reached at (412) 624-2041 and by e-mail: [email protected]. Dr. Tietjen can be reached at (419) 383-6187. (Please do not publish contact information.)