A randomized trial of oral contraceptive and hormone replacement therapy on bone mineral density and coronary heart disease risk factors in postmenopausal women.

OBJECTIVE

To identify the effects of oral contraceptive (OC) and hormone replacement therapy (HRT) on bone mineral density and coronary heart disease risk factors in postmenopausal women.

METHODS

Eighty healthy postmenopausal women were randomly assigned to a cyclic regimen of OC containing 30 microg of ethinyl estradiol and 150 microg of desogestrel or HRT containing 0.625 mg of conjugated equine estrogens 21 days per cycle and 5 mg of medrogestone 10 days per cycle for 12 months. Bone mineral density of lumbar spine and hip, biochemical markers of bone turnover, lipid-lipoprotein profiles, coagulation profiles, fasting plasma glucose, and blood pressure were evaluated.

RESULTS

Both regimens caused significant increase in bone mineral density of lumbar spine, trochanter, intertrochanteric region, total hip, and Ward triangle. Only OC therapy was associated with a significant increase in femoral neck bone mineral density (mean score +/- standard error 2.5% +/- 0.7%, P < .01). Biochemical markers of bone turnover, total cholesterol, and low-density lipoprotein cholesterol decreased significantly in both groups. Posttreatment levels of those bone markers and lipid-lipoprotein were significantly lower after OC therapy than HRT. Fasting plasma glucose and systolic blood pressure decreased significantly in both groups; however, only the OC group showed a significant decrease in diastolic blood pressure.

CONCLUSION

Both OC and HRT increased bone mineral density of lumbar spine and hip, but OC suppressed bone turnover more than HRT. Both methods favorably affected lipid-lipoprotein metabolism, fasting plasma glucose, and blood pressure during the 12 months of treatment.