Soy use and vasomotor symptoms: Soy Estrogen Alternative follow-up study

Mara Z Vitolins¹, L Douglas Case¹, Timothy M Morgan¹, Margaret A Miller², Gregory L Burke^1
1Division of Public Health Sciences, Wake Forest University Health Sciences, Winston-Salem, North Carolina, ²National Center for Toxicology Research, Food and Drug Administration Rockville, Maryland, USA

Purpose: To evaluate vasomotor symptoms and soy and hormone therapy use in women who had previously participated in the Soy Estrogen Alternative (SEA) study, a trial conducted to compare the effects of soy protein supplements containing differing levels of isoflavones on menopausal symptoms, chronic disease risk factors, and health-related quality of life in perimenopausal and postmenopausal women.
Participants and methods: Two years after the SEA study ended participants were recontacted to complete questionnaires to quantify their health status, medications, menopausal symptoms, and their use of hormone therapy and soy-based foods and supplements. Participants were also asked to record vasomotor symptoms for seven days.
Results: Surveys were collected from 182 of the 241 participants who had been enrolled in the SEA study (76% response rate). Women were 55 ± 2.8 years of age, well educated (80% more than high school), and 93% reported good to excellent health. All but six reported experiencing at least one menopausal symptom, and 56% reported one or more hot flashes on one or more days. Eighty-one women (45%) continued to use soy for menopausal symptom relief, and 58 (32%) were using hormone therapy. Women taking hormone therapy were experiencing fewer and less severe hot flashes than those who were not taking hormone therapy (P < 0.001); hot flash frequency and severity did not differ significantly between those who did and did not use soy, after controlling for hormone therapy use.
Conclusion: Most participants reported they were still experiencing menopausal symptoms. Additionally, half of the most symptomatic women (not taking hormone therapy) were still consuming soy products for vasomotor symptoms.

Keywords: menopause, vasomotor symptoms, soy consumption, survey