Bioidentical Hormones Medical Research Studies

Estrogen Plus Progestin and Breast Cancer Incidence and Mortality in Postmenopausal Women

October, 2010Conclusion: In the Women’s Health Initiative randomized, placebo-controlled trial of estrogen plus progestin, after a mean intervention time of 5.6 (SD, 1.3) years (range, 3.7-8.6 years) and a mean follow-up of 7.9 (SD, 1.4) years, breast cancer incidence was increased among women who received combined hormone therapy. Breast cancer mortality among participants in the trial has not been previously reported.Estrogen plus progestin was associated with greater breast cancer incidence, and the cancers are more commonly node-positive. Breast cancer mortality also appears to be increased with combined use of estrogen plus progestin.
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Safety of testosterone use in women

May, 2009Conclusion: This was a review of the literature looking at the safety of testosterone in women. After a review of the available scientific literature the authors concluded that “the predominant data shows that low dose T use is safe in regards to the breast and endometrium with experimental data suggesting a decrease in estrogen-induced breast epithelial proliferation, and no adverse cardiovascular effects.”
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Experimental Benefits of Sex Hormones on Vascular Function and the Outcome of Hormone Therapy in Cardiovascular Disease

November, 2008Conclusion: Conclusion: A review article that looked at hormone replacement therapy and cardiovascular disease. The authors concluded that the type of hormones used and the route of administration used and age of patients among other factors could affect whether or not hormones decreased the risk of heart disease. Notably they stated that transdermal estrogen confers multiple cardiovascular benefits including relaxation of vascular smooth muscle, vascular relaxation, thickness of arteries, blocks vascular inflammation. The authors also state that progesterone has positive effects on lipids and atherosclerosis. Progesterone added to estrogen seems to improve cardiovascular outcomes even further according to the authors. Finally the authors also noted that Testosterone is anti-atherosclerotic and may exert beneficial effects on the arteries. It was also noted that Testosterone causes vasodilation. DHEA also stimulates nitric oxide in human endothelial cells which leads to vasodilation.
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Effect of estrogen plus progestin on stroke in postmenopausal women: the Women’s Health Initiative: a randomized trial

May, 2008Conclusion: The combination of progestin (synthetic progesterone) and Premarin (synthetic estrogen made from horse urine) significantly increased risk of stroke in the WHI study. Large study of 16,608 women over the course of 5.6 years.
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Unequal risks for breast cancer associated with different hormone replacement therapies: results from the E3N cohort study

January, 2008Conclusion: Conclusion: E3N cohort study report from 2008: There was a significantly increased risk of breast cancer in women treated with estrogen combined with progestin but no increased risk in women treated with estrogen combined with progesterone and authors conclude that findings suggest that it could be preferable to use progesterone over progestins.
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Effects of conjugated equine estrogen on stroke in the Women’s Health Initiative

May, 2006Conclusion: Women who took Premarin (synthetic estrogen made from horse urine) had a significantly increased risk of strokes over women who did not take Premarin.
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Breast cancer risk in relation to different types of hormone replacement therapy in the E3N-EPIC cohort

April, 2005Conclusion: 54,548 women on HRT for 5.8 yrs, mean age 52.8 yrs E3N/EPIC trial. Conclusions: When estrogen was combined with progestin the risk of breast cancer was significantly higher than for estrogen combined with natural progesterone.
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Increased risk of breast cancer following different regimens of hormone replacement therapy frequently used in Europe

May, 2004Conclusion: Progestins combined with estrogens increase the risk of breast cancer. Surveys were sent to 19,898 women – The Danish Nurse Cohort. 244 women got breast cancer. The women who were treated with estrogen alone had an increased risk of breast cancer, but the women treated with combined estrogen and progestin had the highest risk of breast cancer.
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Differential effects of progestogens on breast cancer cell lines

December, 2001Conclusion: Looks at effects of different types of progestogens on breast cancer cells. Proved that progesterone caused death and regression (apoptosis) of breast cancer cells whereas progestins (artificial progesterone) proliferation (growth) of breast cancer cells.
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Hormone Replacement Therapy and Cognition

June, 2001Conclusion: 9 randomized controlled trials and 8 cohort studies that studied the effects of HRT on cognition were reviewed. Cognitive function improved in symptomatic women especially in tests of verbal memory and vigilance. 10 case control and 2 cohort studies showed that HRT users have a 34 percent decreased risk of Alzheimers disease.
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Natural progesterone, but not medroxyprogesterone acetate, enhances the beneficial effect of estrogen on exercise-induced myocardial ischemia in postmenopausal women

December, 2000Conclusion: Several studies including this one and HERS showed that the choice of progestin is an important factor especially in high risk women with a history of cardiovascular disease. In this study, women with known cardiovascular disease were studied. They were taken off their medications for heart disease (anti-angina meds). They were treated with estradiol for 4 weeks. Then they either received natural progesterone gel or medroxyprogesterone acetate (MPA) for 12 days. Then they continued without a progesterone or progestin for another 16 days and then they were given the opposite form of progesterone or progestin (cross over study design). Exercise testing was performed after each phase. The time until patients had chest pain (angina) was measured and was found to be significantly longer with patients taking a combination of estradiol with progesterone than patients taking estradiol with MPA. The addition of the progesterone also improved the exercise time compared to estradiol by itself.
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Efficacy and safety of oral estriol for managing postmenopausal symptoms

February, 2000Conclusion: This is a Japanese study which looked at 68 women and the efficacy and safety of oral estriol. The women had improvement in menopausal symptoms especially hopt flushes, night sweats and insomnia. After one year ultrasound of the breasts and the endometrium was normal. The conclusion of the study was that estriol is safe and effective for relieving climacteric symptoms.
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Estradiol and Progesterone Regulate the Proliferation of Human Breast Epithelial Cells

November, 1998Conclusion: Estradiol will increase proliferation (growth) of normal breast cells but when add progesterone for 14 days the growth is significantly inhibited. Shows the necessity for progesterone in breast tissue when estrogen is used.
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Estriol: Safety and Efficacy

April, 1998Conclusion: Literature review of prior estriol studies. Prior studies showed significant improvement in menopausal symptoms. Unopposed estrogens have been shown in several studies to decrease risks of cardiovascular disease and estriol was specifically found effective in improving lipid parameters in a Japanese study. Estriol has been shown not to increase blood pressure as some other HRT regimens have been shown to. Estriol has been shown to have positive effects on the skin. Effects of estriol on bone density are equivocal. Regarding the safety of estriol: Biopsy studies of the endometrium have shown no increased risk of endometrial cancer. Animal studies have shown a protective effect of estriol in breast cancer when rats were exposed to a breast tumor inducing carcinogen. Higher estriol levels have been demonstrated in populations at low risk of breast cancer. One study even showed that estriol decreased or resolved breast cancer metastases.
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The Postmenopausal Estrogen/Progestin Interventions Study: primary outcomes in adherent women

July, 1997 Conclusion: This study looked at 847 women 45-64 yrs old and put them in groups receiving either Premarin (horse urine estrogen), Prempro (horse urine estrogen plus artificial form of progesterone), Premarin plus natural progesterone or placebo. The women who received the estrogen combined with natural progesterone had better HDL (good cholesterol) levels than those who received estrogen combined with progestin (artificial progesterone). Also blood sugar was shown to be increased in the group having estrogen with progestin but not in the group that used estrogen plus natural progesterone. Finally, the study showed that the natural progesterone protected the uterine lining from the cancer promoting effects of estrogen alone as well as progestin. So the authors concluded that estrogen combined with natural progesterone is a better choice than estrogen combined with progestin.
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Influences of percutaneous administration of estradiol and progesterone on Human breast epithelial cell cycle in vivo

February, 1997Conclusion: 25 women with NIDDM were treated with estradiol for 3 months in a double blind, cross over, placebo controlled trial. The study showed that when the women were on estradiol their levels of SHBG were increased which decreased their excess levels of androgens which overall significantly decreased glucose, hemoglobin a1c, LDL cholesterol and raised HDL cholesterol. Also IGF-1, a marker for growth hormone, increased significantly.
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Estrogen Replacement Therapy Decreases Hyperandrogenicity and Improves Glucose Homeostasis and Plasma Lipids in Postmenopausal Women With Noninsulin-Dependent Diabetes Mellitus

August, 1996Conclusion: 25 women with NIDDM were treated with estradiol for 3 months in a double blind, cross over, placebo controlled trial. The study showed that when the women were on estradiol their levels of SHBG were increased which decreased their excess levels of androgens which overall significantly decreased glucose, hemoglobin a1c, LDL cholesterol and raised HDL cholesterol. Also IGF-1, a marker for growth hormone, increased significantly.
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Effect of estrogen during menopause on risk and age at onset of Alzheimer’s disease

August, 1996Conclusion: A study was conducted amongst 1124 elderly women. In the women who had taken hormone replacement therapy that included estrogens their risk of Alzheimer’s disease was significantly reduced or if they did get Alzheimer’s disease the onset of the disease was significantly later in life.
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A Controlled Trial of Intravaginal Estriol in Postmenopausal Women with Recurrent Urinary Tract Infections

September, 1993Conclusion: Vaginal estriol was used in 93 postmenopausal women and shown to provide significant relief from urinary tract infections. The women who used the estriol were found to have a lower vaginal ph (desireable), return of lactobacilli (more healthy for the vagina) and lower rates of colonization with enterobacter (a pathogenic bacterium). All in all there was a significant decrease in the number of urinary tract infections experienced by these women likely because of changes in vaginal microflora.
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The effect of percutaneous estradiol and natural progesterone on postmenopausal bone loss

January, 1987Conclusion: Estrogen transdermal (through the skin) with natural progesterone maintained bone density as opposed to a placebo group that lost 5 to 7% of their bone density over two years of treatment in menopausal women.
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Long-term effects of percutaneous estrogens and oral progesterone on serum lipoproteins in postmenopausal women

January, 1987Conclusion: This study looked at 847 women 45-64 yrs old and put them in groups receiving either Premarin (horse urine estrogen), Prempro (horse urine estrogen plus artificial form of progesterone), Premarin plus natural progesterone or placebo. The women who received the estrogen combined with natural progesterone had better HDL (good cholesterol) levels than those who received estrogen combined with progestin (artificial progesterone). Also blood sugar was shown to be increased in the group having estrogen with progestin but not in the group that used estrogen plus natural progesterone. Finally, the study showed that the natural progesterone protected the uterine lining from the cancer promoting effects of estrogen alone as well as progestin. So the authors concluded that estrogen combined with natural progesterone is a better choice than estrogen combined with progestin.
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