Transdermal estrogen replacement therapy and plasma lipids in 693 French women

The cardiovascular effects of transdermal estrogen are not so well established than those induced by oral estrogen. In a representative sample of French postmenopausal women, we assessed plasma lipid changes induced by transdermal 17 beta-estradiol.

This cross-sectional study was carried out among the population sample of the third MONICA survey on cardiovascular risk factors. We selected 693 postmenopausal women according to the followed criteria; women with intact uterus and no menstruation for more than 12 months, women with bilateral oophorectomy, hysterectomized women older than 55 years and hysterectomized women who had followed hormone replacement therapy. We used multivariate linear regression models, taking into account confounding variables, to assess lipid changes induced by estrogen.

We compared 192 women currently taking transdermal 17 beta-estradiol (27 unopposed estrogen and 165 estrogen plus progestin) with 501 women without any hormonal treatment. After adjustment for living area, education level, income tax, smoking, alcohol consumption, physical activity, age and body mass index, transdermal estrogen replacement therapy (ERT) was significantly associated with lower levels of serum total cholesterol [6.10 (S.E., 0.11) vs 6.35 (0.09) mmol/l, P < 0.01], triglycerides [1.06 (0.06) vs 1.23 (0.05) mmol/l, P < 0.001], LDL-cholesterol [3.93 (0.11) vs 4.13 (0.09) mmol/l, P < 0.05], VLDL-cholesterol [0.48 (0.03) vs 0.56 (0.02) mmol/l, P < 0.001] and apolipoprotein B [1.20 (0.03) vs 1.26 (0.02) g/l, P < 0.01]. Levels did not differ significantly for HDL-cholesterol [1.68 (0.05) vs 1.66 (0.04) mmol/l] and apolipoprotein A1 [1.79 (0.03) vs 1.81 (0.02) g/l].

Transdermal ERT may confer a cardiovascular protection by lowering atherogenic lipoproteins.