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Soy Estrogen Alternative Study (SEA)

This study has been completed.
Information provided by:
National Heart, Lung, and Blood Institute (NHLBI) Identifier:
First received: October 27, 1999
Last updated: May 12, 2016
Last verified: November 2000
To conduct a three-armed trial assessing the effect of soy phytoestrogens on menopausal complaints, plasma lipids and lipoproteins, vaginal bleeding and endometrial proliferation, and health related quality of life.

Condition Intervention Phase
Cardiovascular Diseases
Endometrial Hyperplasia
Heart Diseases
Menopausal Complaints
Uterine Diseases
Drug: estrogens, conjugated
Behavioral: diet, soy proteins
Behavioral: dietary supplements
Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Masking: Double-Blind
Primary Purpose: Prevention

Further study details as provided by National Heart, Lung, and Blood Institute (NHLBI):

Study Start Date: January 1996
Study Completion Date: December 1998
Detailed Description:


The results of many studies indicate that estrogen replacement therapy (ERT) reduces the risk of coronary heart disease (CHD) in postmenopausal women. However, less than 9 percent of these women choose to take ERT because of unwanted side effects and concerns about increased risk of cancer associated with ERT. Therefore, alternative therapies are needed.

The isoflavonoids found in soy protein (specifically genistein) have many properties that may reduce the risk of coronary heart disease. These include favorable effects on plasma lipids and coronary artery vasomotion. Furthermore, genistein is a tyrosine kinase (TK) inhibitor with inhibitory effects on thrombin activity and TK receptor-linked mitogens that may be associated with atherogenesis and neointimal formation after angioplasty.


Randomized, double-blind, placebo-controlled. The women were randomized into one of three groups: placebo, conjugated equine estrogens, or soy supplementation. Primary endpoints were the impact on menopausal complaints such as hot flushes, mood lability, anxiety, sleep disturbances; effects on plasma lipids and lipoproteins, including lipoprotein (a); effects on vaginal bleeding and endometrial proliferation; changes in health-related quality of life. Secondary endpoints included: assessment of the impact of these interventions on the progression of carotid artery intimal medial wall thickening as assessed by B-mode ultrasonography; bone density and bone turnover; additional measures to monitor the compliance and safety of the intervention such as mammography, anticipated or known side effects of hormone replacement therapy, blood levels of genistein, and clinical outcomes such as hospitalizations, physician visits, and symptoms. The study ended in December, 1998.

The study was a subproject within a program project on coronary atherosclerosis in females, primarily monkeys. Dr. Thomas B. Clarkson was the P.I. The subproject dollars were estimated based on the CRISP dollars assigned to the study which were approximately 12 percent of the total program project dollars and were broken down as follows: FY 1996 - 219,254; FY 1997 - $217,000; FY 1998 - $221,000.

The study completion date listed in this record was obtained from the "End Date" entered in the Protocol Registration and Results System (PRS) record.


Ages Eligible for Study:   45 Years to 55 Years   (Adult)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   No
Perimenopausal/menopausal women, ages 45 to 55.
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No Contacts or Locations Provided
  More Information

Publications: Identifier: NCT00000612     History of Changes
Other Study ID Numbers: 115
P01HL045666 ( US NIH Grant/Contract Award Number )
Study First Received: October 27, 1999
Last Updated: May 12, 2016

Additional relevant MeSH terms:
Cardiovascular Diseases
Heart Diseases
Uterine Diseases
Genital Diseases, Female
Endometrial Hyperplasia
Pathologic Processes
Estrogens, Conjugated (USP)
Hormones, Hormone Substitutes, and Hormone Antagonists
Physiological Effects of Drugs processed this record on April 28, 2017