New findings also in metabolic syndrome, clinical trials recruitment

By Lynn Schultz-Writsel
School of Nursing

The Beneficial Effects of Soy Trial, a Baltimore-based randomized controlled study of dietary soy, has yielded an array of results pertaining to cholesterol reduction, metabolic syndrome and recruitment for clinical trials. The multidisciplinary study team, led by Jerilyn K. Allen, a Johns Hopkins School of Nursing researcher and lead investigator, reported its findings this month in two journals — Menopause and Ethnicity and Disease — and at the American Heart Association 2006 Scientific Sessions.

In the study now appearing online in Menopause, Allen and co-authors report that among their BEST study group — 216 healthy postmenopausal African-American and white women with moderately elevated low-density lipoprotein cholesterol levels — those who received isolated soy protein containing isoflavones experienced a significant decrease in total cholesterol, LDL cholesterol and lipoprotein particles. LDL levels decreased by an average of 3.3 percent, LDL particles decreased by 5.6 percent, and beneficial high-density lipoprotein cholesterol increased 4.4 percent. Noting that because lipoprotein levels often increase as a consequence of menopause, Allen cautions that while soy protein alone will not lower cholesterol with the same effectiveness as medications, "the modest effects of soy protein on LDL cholesterol and LDL particle number may be beneficial for heart health in postmenopausal women who do not require statins or other medications to control their levels."

At the American Heart Association meeting, Allen and School of Nursing co-authors Sarah Szanton, Kathleen Lindenstruth and Carol Curtis reported additional BEST study findings on factors associated with cardiovascular disease. In "Effect of Metabolic Syndrome on Lipoprotein Subclass Particle Size and Concentration in Postmenopausal Women," the investigators reported on their evaluations of women in the study with metabolic syndrome, a clustering of at least three cardiovascular disease risk factors: high blood pressure, high triglycerides, low levels of HDL cholesterol (good cholesterol), high glucose or abdominal obesity (large waist measurement). When compared to women in the study without the syndrome, those with metabolic syndrome had lower levels of high-density lipoprotein cholesterol and higher levels of triglycerides without significant differences in total cholesterol. However, there were significant differences in major lipoprotein subclass measures, showing that women with metabolic syndrome had smaller mean LDL size, higher LDL particle concentration and smaller mean HDL size, all factors putting them at increased risk for cardiovascular disease.

During the study, investigators also compiled data on recruitment into the clinical trial. Published this month in Ethnicity and Disease, Lindenstruth's analysis — "Recruitment of African-American and White Postmenopausal Women Into Clinical Trials: The Beneficial Effects of Soy Trial Experience" — shows that African-American and white women differed significantly in their response to various forms of mass media and personalized techniques employed to recruit participation in the clinical trial. The most effective mechanism for recruiting African-American women was direct mail (52 percent), followed by radio (15 percent); newspapers were less effective. Conversely, white women responded best to newspaper ads (36 percent), followed by direct mail (32 percent); radio was less effective. These strategies were more effective than personalized techniques — health fairs, provider referrals, newsletters and churches.

The BEST study was funded by the National Heart, Lung and Blood Institute to determine the effects of soy on lipids, lipoproteins and lipoprotein subclasses in a sample of African-American and white postmenopausal women. The women in the study had low-density lipoprotein cholesterol elevations that could increase their lifetime risk for cardiovascular disease but would not qualify them for definitive pharmacotherapy under current guidelines.

The secondary aims of the study were to assess the impact of soy on menopausal quality of life, including menopausal symptoms, and to examine racial/ethnic differences in quality of life, acceptability and adherence to the soy supplementation.

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