Hormone replacement therapy, hormone levels, and lipoprotein cholesterol concentrations in elderly women.

OBJECTIVE: Our purpose was to assess the relationships of lipid and lipoprotein cholesterol levels to hormone replacement therapy and hormone levels in elderly women. STUDY
DESIGN: A sample of 292 postmenopausal women 55 to 99 years old (mean 76 years) was drawn from Leisure World Laguna Hills, California, an upper-middle-class, white independent-living population. We compared 84 women receiving unopposed estrogen replacement therapy and 38 women taking combination hormone replacement therapy with 170 women who had never used hormone replacement therapy. Nonparametric tests for differences in lipid and lipoprotein cholesterol levels among groups and multiple stepwise regression models were used.
RESULTS: Estrogen users (with and without progestin) had lower total and low-density lipoprotein cholesterol and higher high-density lipoprotein and high-density lipoprotein subfraction types 2, 2a, and 2b cholesterol levels. High density lipoprotein type 3 subfractions were lower in combination hormone replacement therapy users but higher in unopposed estrogen users relative to nonusers. The conjugated equine estrogen dose was negatively correlated with total (p = 0.0009) and low-density lipoprotein cholesterol (p <0.0001) levels and positively correlated to high-density lipoprotein cholesterol (p = 0.002) and its subfractions. The medroxyprogesterone acetate dose showed no consistent effect on cholesterol levels.
CONCLUSION: The associations found here reaffirm the significant role of estrogen replacement therapy on lipid and lipoprotein cholesterol levels and provide no evidence of a reduction in the beneficial effect of estrogen with the addition of a progestational agent to the replacement regimen.