Effects of 2 years of hormone replacement upon bone mass, serum lipids and lipoproteins

The objective of this study was to measure the effects on postmenopausal women of 2 years of either a low dose or a moderate dose regimen of hormone replacement upon bone mass and serum cardiovascular risk factors. After 6 months of calcium supplementation, 75 women chose to add hormone replacement or to remain on calcium. Those choosing hormones were randomised to either 0.3 mg/day equine estrogen and 2.5 mg/day medroxyprogesterone or 0.625 mg/day equine estrogen, days 1-25, and 5 mg/day medroxyprogesterone, days 16-25. On calcium only, lumbar spine bone mineral content and radius bone mass fell. Serum concentrations of cholesterol and triglycerides increased while HDL concentration fell. The low dose continuous regime reduced whole body bone turnover and prevented the age related reductions in bone mass and serum cardiovascular risk profile. The moderate dose regimen reduced whole body bone turnover and increased lumbar spine bone mass. Total serum cholesterol was unchanged while HDL levels increased, LDL levels fell and triglyceride concentration increased.