ackground : Postmenopausal women have a high risk of cardiovascular disease than
premenopausal women and hormone replacement therapy [HRT] reduces the risk of
cardiovascular disease. Apolipoprotein(a)[apo(a)] is attached by disulfide linkage to aop B-100
of LDL, forming lipoprotein(a)[Lp(a)]. The level of this lipoprotein is an independent risk
factor for atherosclerosis. The serum level of apo(a) is stable and not affected by most
dietary interventions and lipid lowering agents. There was little information available about
the effect of HRT on levels of Lp(a). This study was conducted to asses the effect of HRT
on serum lipids and apo(a) levels in postmenopausal women.
Methods : Postmenopausal women with serum FSH level above 40 mIU/ml or no
menstruation for more than 1 year were included in the study. They received the
combination of conjugated equine estrogen (CEE) 0.625 mg a day for 25 days plus
medroxyprogesterone acetate 10 mg (group A) or 5 mg (group B) a day for the last 10 days
followed by 5 days off. Hysterectomized women received CEE 0.625 mg a day for 25 days
(group C). HRT was repeated for 2 months. The baseline levels of serum total cholesterol,
triglyceride, LDL cholesterol, VLDL cholesterol, HDL cholesterol, and apo(a) were compared
with posttreatment levels.
Results : Serum total cholesterol levels before treatment were 5.42±.09 mmol/L, 5.59±0.09
mmol/L, 5.53±.13 mmol/L in group A,B,C respectively. After HRT thery were significantly
reduced to 4.93±.08 mmol/L, 5.22±.08 mmol/L in group A,B respectively (p=0.0001).
Serum LDL cholesterol levels before treatment were 3.29±.07 mmol/L, 3.41±.07 mmol/L,
3.40±.10 mmol/L in group A,B,C respectively. After HRT they were significantly reduced to
3.00±.06 mmol/L (p=0.0001), 3.14±.06 mmol/L (p=0.0001), 3.18±.13 mmol/L (p<0.05)in group
A,B,C respectively.
Serum HDL cholesterol levels before treatment were 1.72±.04 mmol/L, 1.75±.04 mmol/L,
1.69±.06 mmol/L in group A,B,C respectively. After HRT they were significantly increased
to 1.90±.07 mmol/L in group C (p=0.0001).
Serum triglyceride levels before treatment were 1.45±.08 mmol/L, 1.54±.08 mmol/L, 1.68
±.15 mmol/L in group A,B,C respectively. After HRT they were not significantly changed.
Serum VLDL cholesterol levels before treatment were 0.39 0.03 mmol/L, 0.40 0.03 mmol/L,
0.45±0.05 mmol/L in group A,B,C respectively. After HRT they were significantly reduced to
0.30± 0.02 mmol/L (p=0.0001), 0.34± 0.03 mmol/L (p<0.05) in group A, B respectively.
Serum apo(a) levels before treatment were 357.5±33.2 U/L, 348.7±28.2 U/L, 376.8±54.2
U/L in group A,B,C respectively. After HRTT they were significantly reduced to 264.7±26.1
U/L 291.0±31.8 U/L, 228.8±47.4 U/L in group A,B,C respectively (p=0.0001).
Conclustion : These results suggest that HRT for 2 months in postmenopausal women has
beneficial effect on serm lipids and apo(a) levels and HRT in postmenopausal women can
improve their cardiovascular risk.
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