At menopause (usually around age 45), women's bodies stop producing the hormone estrogen, contributing to short-term symptoms (hot flashes) and increasing long-term health risks (heart disease, stroke and osteoporosis).

Many women undergo hormone replacment therapy (HRT) to combat these risks, although treatment may cause other complications, including weight gain, pelvic discomfort, breast tenderness and mood changes.

A study of 128 elderly women with low bone mass (a risk factor for osteoporosis) investigated whether low-level hormone replacement could reduce these side effects while still providing the same benefits (especially concerning bone mass) as higher-level HRT.

Women received hormone replacement or a placebo for 3.5 years, and bone density of the spine, hip, forearm and total body was measured at six-month intervals. Calcium and vitamin D supplements were also provided to both groups during the study period.

Bone density of the spine, forearm and total body increased significantly in the hormone replacement group compared to the placebo group. Most encouraging was the observation that the usual side effects of HRT were generally mild and short-lived, often disappearing within six months.

Recker RR, Davies KM, Dowd RM, et al. The effect of low-dose continuous estrogen and progesterone therapy with calcium and vitamin D on bone in elderly women. Annals of Internal Medicine, June 1999: Vol. 130, pp897-904.