Methods We studied the effect of raloxifene, a non-steroidal benzothiophene, on bone mineral density, serum lipid concentrations, and endometrial thickness in 601 postmenopausal women. The women were randomly assigned to receive 30, 60, or 150 mg of raloxifene or placebo daily for 24 months.

Results The women receiving each dose of raloxifene had significant increases from base-line values in bone mineral density of the lumbar spine, hip, and total body, whereas those receiving placebo had decreases in bone mineral density. For example, at 24 months, the mean (+/-SE) difference in the change in bone mineral density between the women receiving 60 mg of raloxifene per day and those receiving placebo was 2.4+/-0.4 percent for the lumbar spine, 2.4+/-0.4 percent for the total hip, and 2.0+/-0.4 percent for the total body (P<0.001 for all comparisons). Serum concentrations of total cholesterol and low-density lipoprotein cholesterol decreased in all the raloxifene groups, whereas serum concentrations of high-density lipoprotein cholesterol and triglycerides did not change. Endometrial thickness was similar in the raloxifene and placebo groups at all times during the study. The proportion of women receiving raloxifene who reported hot flashes or vaginal bleeding was not different from that of the women receiving placebo.

Conclusions Daily therapy with raloxifene increases bone mineral density, lowers serum concentrations of total and low-density lipoprotein cholesterol, and does not stimulate the endometrium. (C) 1997, Massachusetts Medical Society.