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Low Dose Hormone Replacement Therapy Prevents Osteoporosis, Minimizes Negative Side Effects

Hormone replacement therapy (HRT), a common treatment for osteoporosis, is not used by some women because it causes a variety of negative side effects. However, a recent study published in the Annals of Internal Medicine reveals that low dose HRT, when used in conjunction with calcium and vitamin D supplements, can improve bone density in post-menopausal women as effectively as standard doses of HRT but with fewer side effects.

Researchers studied 128 healthy post-menopausal women 65 years of age or older who had below average bone density. The women were randomly assigned to take either low dose HRT (0.3 milligrams of conjugated estrogen with 2.5 milligrams of progesterone each day) or a placebo (ineffective pill) for three and a half years. All women also took calcium and vitamin D supplements to raise their daily nutrient intake to sufficient levels. Every six months, researchers measured the women’s total bone density as well as bone mass in the spine, hip, and forearm.

The results of the study revealed that after three and a half years, the women treated with low dose HRT with calcium and vitamin D supplements increased their spinal bone density by 3.5% to 5.3%. The researchers also noted significant increases in total body and forearm bone densities in the women who were on low dose HRT.

In addition to increasing bone density, low dose HRT reduced common negative side effects of standard dose HRT which include breast tenderness, spot bleeding, pelvic discomfort, and mood changes. Incidence of these side effects was minimal during the study and the majority subsided after six months of treatment.

Prior to the study, researchers believed the lowest effective dose of conjugated estrogen was 0.625 milligrams (mg) per day. The standard dosage of conjugated estrogen is between 0.625 mg and 1.25 mg daily. Some post-menopausal women who use standard dose HRT experience negative side effects such as bloating, nausea, breast tenderness, vaginal bleeding, fluid retention, weight gain, or depression.

The purpose of HRT is to "replace" female hormones (estrogen and/or progesterone) which the ovaries stop producing at menopause. Besides helping to prevent osteoporosis, HRT has been shown to prevent or improve a variety of other conditions including: menopausal symptoms (such as hot flashes or vaginal dryness), heart disease , Alzheimer’s disease , and Type II diabetes .

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