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Effects of a 2-year randomized soy intervention on sex hormone levels in premenopausal women.

Abstract

OBJECTIVE

Several epidemiologic studies have described protective effects of soy consumption against breast cancer. The goal of this trial among premenopausal women was to examine the effect of soy foods on menstrual cycle length and circulating sex hormone levels.

METHODS

This 2-year dietary intervention randomized 220 healthy premenopausal women. The intervention group consumed two daily servings of soy foods containing approximately 50 mg of isoflavones; the control group maintained their regular diet. Five blood samples (obtained in months 0, 3, 6, 12, and 24) were taken 5 days after ovulation as determined by an ovulation kit. The serum samples were analyzed for estrone, estradiol, sex hormone binding globulin, androstenedione, and progesterone by immunoassay.

RESULTS

At baseline, both groups had similar demographic, anthropometric, and nutritional characteristics. The dropout rates of 15.6% (17 of 109) in the intervention group and 12.6% (14 of 111) in the control group did not differ significantly. According to soy intake logs, 24-hour recalls, and urinary isoflavone excretion, the women closely adhered to the study regimen. Menstrual cycles became slightly shorter in both groups but did not differ by group. Mixed general linear models indicated no significant intervention effect on any of the serum hormones. However, androstenedione and progesterone decreased significantly over time in both groups.

CONCLUSIONS

The results of this study suggest that the preventive effects of soy on breast cancer risk in premenopausal women may not be mediated by circulating sex hormone levels. Different mechanisms of actions or effects of exposure earlier in life are alternate hypotheses that require further investigation.

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  • Authors+Show Affiliations

    ,

    Cancer Research Center of Hawaii, 1236 Lauhala Street, Honolulu, HI 96813, USA. gertraud@crch.hawaii.edu

    , , , , ,

    Source

    MeSH

    Adult
    Breast Neoplasms
    Diet
    Female
    Gonadal Steroid Hormones
    Humans
    Isoflavones
    Menstrual Cycle
    Middle Aged
    Premenopause
    Soybean Proteins

    Pub Type(s)

    Clinical Trial
    Journal Article
    Randomized Controlled Trial
    Research Support, U.S. Gov't, P.H.S.

    Language

    eng

    PubMed ID

    15533901

    Citation

    Maskarinec, Gertraud, et al. "Effects of a 2-year Randomized Soy Intervention On Sex Hormone Levels in Premenopausal Women." Cancer Epidemiology, Biomarkers & Prevention : a Publication of the American Association for Cancer Research, Cosponsored By the American Society of Preventive Oncology, vol. 13, no. 11 Pt 1, 2004, pp. 1736-44.
    Maskarinec G, Franke AA, Williams AE, et al. Effects of a 2-year randomized soy intervention on sex hormone levels in premenopausal women. Cancer Epidemiol Biomarkers Prev. 2004;13(11 Pt 1):1736-44.
    Maskarinec, G., Franke, A. A., Williams, A. E., Hebshi, S., Oshiro, C., Murphy, S., & Stanczyk, F. Z. (2004). Effects of a 2-year randomized soy intervention on sex hormone levels in premenopausal women. Cancer Epidemiology, Biomarkers & Prevention : a Publication of the American Association for Cancer Research, Cosponsored By the American Society of Preventive Oncology, 13(11 Pt 1), pp. 1736-44.
    Maskarinec G, et al. Effects of a 2-year Randomized Soy Intervention On Sex Hormone Levels in Premenopausal Women. Cancer Epidemiol Biomarkers Prev. 2004;13(11 Pt 1):1736-44. PubMed PMID: 15533901.
    * Article titles in AMA citation format should be in sentence-case
    TY - JOUR T1 - Effects of a 2-year randomized soy intervention on sex hormone levels in premenopausal women. AU - Maskarinec,Gertraud, AU - Franke,Adrian A, AU - Williams,Andrew E, AU - Hebshi,Sandra, AU - Oshiro,Caryn, AU - Murphy,Suzanne, AU - Stanczyk,Frank Z, PY - 2004/11/10/pubmed PY - 2005/2/3/medline PY - 2004/11/10/entrez SP - 1736 EP - 44 JF - Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology JO - Cancer Epidemiol. Biomarkers Prev. VL - 13 IS - 11 Pt 1 N2 - OBJECTIVE: Several epidemiologic studies have described protective effects of soy consumption against breast cancer. The goal of this trial among premenopausal women was to examine the effect of soy foods on menstrual cycle length and circulating sex hormone levels. METHODS: This 2-year dietary intervention randomized 220 healthy premenopausal women. The intervention group consumed two daily servings of soy foods containing approximately 50 mg of isoflavones; the control group maintained their regular diet. Five blood samples (obtained in months 0, 3, 6, 12, and 24) were taken 5 days after ovulation as determined by an ovulation kit. The serum samples were analyzed for estrone, estradiol, sex hormone binding globulin, androstenedione, and progesterone by immunoassay. RESULTS: At baseline, both groups had similar demographic, anthropometric, and nutritional characteristics. The dropout rates of 15.6% (17 of 109) in the intervention group and 12.6% (14 of 111) in the control group did not differ significantly. According to soy intake logs, 24-hour recalls, and urinary isoflavone excretion, the women closely adhered to the study regimen. Menstrual cycles became slightly shorter in both groups but did not differ by group. Mixed general linear models indicated no significant intervention effect on any of the serum hormones. However, androstenedione and progesterone decreased significantly over time in both groups. CONCLUSIONS: The results of this study suggest that the preventive effects of soy on breast cancer risk in premenopausal women may not be mediated by circulating sex hormone levels. Different mechanisms of actions or effects of exposure earlier in life are alternate hypotheses that require further investigation. SN - 1055-9965 UR - https://www.unboundmedicine.com/medline/citation/15533901/Effects_of_a_2_year_randomized_soy_intervention_on_sex_hormone_levels_in_premenopausal_women_ L2 - http://cebp.aacrjournals.org/cgi/pmidlookup?view=long&pmid=15533901 DB - PRIME DP - Unbound Medicine ER -