Three-year study of estrogen alone versus combined with progestin in postmenopausal women with or without hypercholesterolemia

Differential effect of hormone therapy and tibolone on lipids, lipoproteins, and the atherogenic index of plasma

The aim of our study was to assess the effect of various regimens and doses of hormone therapy and tibolone on the Atherogenic Index of Plasma (AIP). A total of 519 postmenopausal women attending our menopause clinic were studied in a prospective design. Women with climacteric symptoms were randomly assigned to receive 1 of the following regimens: tibolone 2.5 mg, conjugated equine estrogens 0.625 mg plus medroxyprogesterone acetate 5 mg (CEE/MPA), 17beta-estradiol 2 mg plus norethisterone acetate 1 mg (E2/NETA), or 17beta-estradiol 1 mg plus norethisterone acetate 0.5 mg (low E2/NETA). Serum parameters were assessed at baseline and after 6 months and included total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, apolipoprotein A1 and apolipoprotein B. The AIP was assessed as the log (triglycerides [mmol/L]/HDL-C [mmol/L]). CEE/MPA treatment associated with lower mean LDL-C but higher mean triglyceride levels (-15.5 mg/dL +/- 3.6, P = 0.0001; 12.6 mg/dL +/- 4.8, P = 0.01). Furthermore, CEE/MPA treatment resulted in higher AIP levels (0.073 +/- 0.021, P = 0.001). On the contrary, both E2/NETA regimens and tibolone associated with lower mean triglyceride and HDL-C levels (E2/NETA, triglycerides: -9.8 mg/dL +/- 5.0, P = 0.049; HDL-C: -4.9 mg/dL +/- 1.8, P = 0.01, low E2/NETA triglycerides: -12.5 mg/dL +/- 4.1, P = 0.003; HDL-C: -4.7 mg/dL +/- 1.3, P = 0.001; tibolone, triglycerides: -21.9 mg/dL +/- 2.7, P = 0.0001; HDL-C: -12.7 mg/dL +/- 1.1, P = 0.0001). None of the 3 regimens had any effect on AIP. The effect of a particular regimen of hormone therapy on the lipid-lipoprotein profile differs depending on the parameter assessed. The use of unified markers such as AIP will be helpful in evaluating the overall effect of lipid-lipoprotein modulation on the cardiovascular system. In fact, the concurrent assessment of the therapy effect on both LDL-C and AIP may be more dependable in evaluating the cardiovascular impact of a given regimen.

Relation of long chain n-3 polyunsaturated fatty acid intake to serum high density lipoprotein cholesterol among Japanese men in Japan and Japanese-American men in Hawaii: the INTERLIPID study

Epidemiologic evidence shows an inverse relationship between fish consumption and coronary heart disease (CHD) mortality. Associations between dietary intake of long chain n-3 polyunsaturated fatty acids (PUFA) and serum high density lipoprotein (HDL) cholesterol concentration are unknown. In this study, the association between n-3 PUFA (eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and docosapentaenoic acid (DPA)) intake and serum HDL cholesterol among Japanese men and women in Japan and Hawaii was examined. The study population consisted of Japanese ancestries from five research centers of the International Study of Macronutrients and Blood Pressure (INTERMAP) study, in Japan and Hawaii (672 men and 676 women), surveyed between 1996 and 1998. Four 24-h dietary recalls and one set of serum lipid measurements were performed. For men, n-3 PUFA intake and HDL cholesterol were higher in Japan than in Hawaii (n-3 PUFA: 1.32 g/day versus 0.47 g/day, p<0.001). For women, n-3 PUFA intake was higher in Japan than in Hawaii (p<0.001) but HDL cholesterol was not significantly different (p=0.752). After adjustment for age, body mass index, physical activity, number of cigarettes per day, alcohol intake, and hormone replacement therapy (for women), n-3 PUFA intake was positively associated with serum HDL cholesterol in men (4.6 mg/dl higher HDL cholesterol with 1%kcal higher n-3 PUFA intake, p=0.011). This association was not observed in women. This positive association of dietary n-3 PUFA with serum HDL cholesterol may partially explain the low mortality from CHD among Japanese men.

The HDL2/HDL3 ratio in menopause

OBJECTIVES

The influence of the menopause on the HDL2/HDL3 ratio was assessed in association with hypertriglyceridemia.

METHODS

Fasting blood samples were collected from 607 patients. Commercially available enzymatic methods were used for determination of TG, and total HDL-C. HDL2 and HDL3 were measured by ultracentrifugation.

RESULTS

The HDL2/HDL3 ratio had a strong negative correlation with TG (r=-0.272, P<0.0001 and r=-0.314, P<0.0001) in both pre- and postmenopausal women. No significant differences were observed in HDL2, HDL3, and HDL2/HDL3 ratio between pre- and postmenopausal women without hypertriglyceridemia. Postmenopausal women had a significantly higher HDL2/HDL3 ratio than premenopausal women with hypertriglyceridemia.

CONCLUSIONS

These results indicate that menopausal status not only increases plasma LDL-cholesterol and triglyceride levels, but also increases the HDL2/HDL3 ratio when associated with elevation of plasma triglyceride levels. These changes may increase the risk for CHD due to enlargement of the lipid pool.

Effect of hormone replacement therapy, tibolone and raloxifene on serum lipids, apolipoprotein A1, apolipoprotein B and lipoprotein(a) in Greek postmenopausal women

The aim of this study was to assess the effect of estrogen, two regimens of continuous combined hormone replacement therapy (HRT), tibolone and raloxffene on serum lipid, apolipoprotein A1 and B and lipoprotein(a) levels in Greek postmenopausal women. A total of 350 postmenopausal women were studied in a prospective open design. Women were assigned to one of the following regimens depending on the presence of risk factors for osteoporosis, dimacteric symptoms and an intact uterus: conjugated equine estrogen 0.625 mg (CEE, n = 34), continuous combined CEE 0.625 mg plus medroxyprogesterone acetate (MPA) 5 mg, (n = 80), continuous combined 17beta-estradiol 2 mg plus norethisterone acetate (NETA) 1 mg (n = 58), tibolone 2.5 mg (n = 83) and raloxifene HCl 60 mg (n = 50). Forty-five postmenopausal women with no indications for HRT served as controls. Total cholesterol (TC), low-density lipoprotein (LDL) cholestrol and high-density lipoprotein (HDL) cholesterol, triglyceride (TG), apolipoprotein A1 (ApoA1), apolipoprotein B (ApoB) and lipoprotein(a) (Lp(a)) levels were assessed in each subject at baseline, and at 6 and 12 months of therapy. All therapy regimens lowered TC levels compared to baseline (4.2-8.0% decrease). This effect was more prominent in the subgoup of women with high baseline TC levels (9.1-20.4% decrease). LDL cholesterol decreased significantly in CEE, CEE/MPA and raloxifene groups (-11.2%, -11.9% and -11.0%, respectively). Hypercholesterolemic women exhibited a steeper decrease in LDL cholesterol (10.6-27.8% in all therapy groups). TG levels increased significantly in the CEE and CEE/MPA groups (23.7% and 21.8%, respectively), while estradiol/NETA had no effect on TG levels. Tibolone decreased TG levels markedly, by 20.6%, while raloxifene had no TG-lowering effect. HDL cholesterol and ApoA1 were increased by CEE and CEE/MPA (HDL cholesterol, 7.4% and 11.8%, respectively; ApoA1, 17.8% and 7.9%, respectively) and decreased by tibolone (HDL cholesterol, -13.6%; and ApoA1, -9.9%). All therapy regimens except raloxifene lowered Lp(a) levels, with tibolone having the more pronounced effect (-13.2 to -29.0%). In conclusion, each therapy regimen had a diferent effect on lipid-lipoprotein levels, exerting favorable and unfavorable modifications. Hypercholesterolemic women seemed to benefit more from the cholesterol-lowering effect of estrogen replacement therapy/HRT. The choice for a particular regimen should be based on individual needs, indications and lipid-lipoprotein profile.

Biology: risk factor modification by OCs and HRT lipids and lipoproteins

The many effects that the oestrogens and progestagens used in oral contraceptive (OC) and postmenopausal hormone replacement therapies (HRTs) have on lipoprotein metabolism are of importance because of the involvement of lipoproteins in endothelial damage and arterial occlusion. Lipoproteins promoting endothelial damage include: low density lipoprotein (LDL), particularly the small dense subfraction (sdLDL), remnants of very low density lipoprotein (VLDL) and chylomicron metabolism, and lipoprotein (a). High density lipoprotein (HDL) has pleiotropic effects that prevent or alleviate endothelial damage. Orally administered oestrogens increase hepatic triglyceride synthesis and VLDL secretion and increase the proportion of sdLDL. Oestrogens increase the rates of elimination of LDL, VLDL remnants and chylomicrons, suppress the synthesis of key enzymes of lipoprotein metabolism, hepatic and lipoprotein lipase, and increase synthesis of the principal apoprotein of HDL, apoAI. In general, progestagens oppose these effects according to type and dose. In OC and HRT users, this leads to a range of different lipoprotein profiles, which may differ from those evaluated with respect to vascular disease risk in population studies. Accumulating evidence suggests that the clinical implications of steroid induced changes in the lipoprotein profile will need to be evaluated independently of population-based evidence.

Associated response in bone and lipids during hormone replacement therapy

OBJECTIVE

In postmenopausal women, we investigated if the response in bone mineral density (BMD) was associated with the response in the atherogenic lipid profile during hormone replacement therapy.

METHODS

We performed an exploratory, post-hoc analysis of data from a prospective double-blind placebo-controlled trial. Healthy postmenopausal women were randomised into five groups, each receiving different combinations of 17 beta-estradiol and gestodene or placebo. A total of 133 women completed the study. The study period was 3 years. The response in bone mass was expressed as the percentage change in BMD from baseline calculated by linear regression from semi-annual measurements. The change in lipid profile was evaluated as the average of three mid-cycle and end-cycle values in percentage from baseline in order to account for cyclic changes during sequential hormone therapy.

RESULTS

A significant correlation between the increase in BMD of the spine and hip and forearm with the decrease in serum low density lipoprotein (LDL) and cholesterol was found. Additionally, the decrease in atherogenic lipids correlated significantly with the response in biochemical bone markers for resorption and formation.

CONCLUSION

In conclusion, our study shows that it is the same women who have a favourable response in BMD as in the lipid-profile during hormone replacement therapy (HRT). The association is most likely driven by a common response in FSH to exogenous estradiol therapy. This indicates that common denominators for the response to HRT exist. Further studies are needed to explore and identify such predictors.

Serum lipids and apolipoproteins in Greek postmenopausal women: association with estrogen, estrogen-progestin, tibolone and raloxifene therapy

The aim of this study was to assess lipid and apolipoprotein levels in postmenopausal women taking various regimens of replacement therapy or no therapy. Seven hundred forty-eight postmenopausal women followed in the Menopause Clinic of the 2nd Department of Obstetrics and Gynecology, University of Athens, Aretaieion Hospital, were studied in a cross-sectional design. Women were either non-users of replacement therapy (no. = 511) or users of one of the following regimens: conjugated equine estrogen 0.625 mg (CEE, no. = 34), CEE 0.625 mg plus medroxyprogesterone acetate 5 mg (CEE/MPA, no. = 60), 17beta-estradiol 2 mg plus norethisterone acetate 1 mg (E2/NETA, no. = 44), tibolone 2.5 mg (no. = 84), raloxifene HCI 60 mg (no. = 51). Total cholesterol (TC), LDL-cholesterol (LDL-C) and HDL-cholesterol (HDL-C), triglycerides (TG), apolipoprotein A1 (ApoA1) and apolipoprotein B (ApoB) levels were assessed. Women were grouped according to replacement regimen and mean levels of lipid and apolipoproteins were compared between groups. Women in the raloxifene group were older and longer menopaused. After adjustment for age and duration of menopause, TG levels were significantly lower in the tibolone and E2/NETA groups (75 and 89.9 mg/dl, respectively) compared to non-users. TC was lower in all therapy groups, but the difference acquired significance only in the E2/NETA (207.8 mg/dl), compared to non-users (231.5 mg/dl). LDL-C levels were significantly lower in the CEE (133.8 mg/dl), CEE/MPA (130.4 mg/dl) and raloxifene group (129.9 mg/dl) compared to non-users (151.9 mg/dl). There was no difference in HDL-C levels between users and non-users (58.9 mg/dl) except for the tibolone group where HDL-C was significantly lower (48.6 mg/dl). ApoA1 levels were significantly higher in the CEE/MPA group (194.4 mg/dl) and significantly lower in the tibolone group (141.6 mg/dl) compared to non-users (170.4 mg/dl). No difference was detected between groups concerning ApoB levels. In conclusion, tibolone therapy is associated with lower TG levels as well as lower HDL and ApoA1 levels. ERT, continuous combined estrogen-progestin therapy (HRT) and raloxifene are associated with lower LDL-C levels. Among continuous combined HRT users, CEE/MPA is associated with higher ApoA1 levels, while E2/NETA with lower TG levels. Large prospective randomized studies are required to validate these results.

Combination therapy of low-dose medroxyprogesterone acetate and oral estrogen does not affect endothelial function in the forearms of postmenopausal women

OBJECTIVE

We investigated whether low-dose medroxyprogesterone acetate (MPA) combined with oral estrogen had adverse effects on endothelial function compared with oral estrogen alone in postmenopausal women with mild hypercholesterolemia.

DESIGN

Subjects were divided into two groups. One group received conjugated equine estrogen (CEE, 0.625 mg daily) orally for the first 3 months, followed by estrogen combined with MPA (2.5 mg daily) orally for an additional 3 months ( = 26). The other group received no treatment (control group, = 12). Forearm blood flow (FBF) during reactive hyperemia and after sublingual nitroglycerin administration was measured by strain-gauge plethysmography. Nitrite/nitrate, angiotensin-converting enzyme, and lipid concentrations were measured in the serum.

RESULTS

Both CEE and CEE combined with MPA significantly increased the FBF during reactive hyperemia. This increase was similar in both active treatment phases. No changes were seen in controls. FBF after sublingual nitroglycerin did not change over 6 months in either group. Significant and similar increases in serum concentration of nitrite/nitrate and plasma renin activity as well as decreases in angiotensin-converting enzyme activity were found in both treatment phases. No such changes occurred in the control group. There was no significant increase in high-density lipoprotein cholesterol or decrease in low-density lipoprotein cholesterol between the treatment phases. Likewise, no such changes were observed in the control group.

CONCLUSIONS

Our 6-month study suggests that the addition of low-dose MPA with CEE had no adverse effects on forearm resistance artery endothelial function compared with CEE alone.

Effects of a lipid lowering fibrate and hormone replacement therapy on serum lipids and lipoproteins in overweight postmenopausal women with elevated triglycerides

BACKGROUND

Cardiovascular disease (CVD) is the leading cause of death in women after menopause. In essence major risk factors for CVD are similar in women as for men inclusive of serum lipid perturbations. The effects of estrogens and hormone replacement therapy on lipid metabolism is widely discussed and warrant further evaluation especially when combined with other lipid lowering drugs.

STUDY DESIGN

Postmenopausal women were studied by an open randomised study during 9 months. Subjects were recruited from outpatient clinics in a rural area of Sweden. Major inclusive criteria comprised body mass index (BMI) >28, serum triglycerides >1.5 mmol/l. Participants were at least 12 months postmenopause with a concomitant serum Follicle Stimulating Hormone (FSH) above 28 IU/l. After inclusion in the study patients were instructed to adhere to a low-fat and caloric diet for 3 months and after this period randomised into two groups of intervention; a lipidlowering fibrate (LLF) group and one hormone replacement therapy group (HRT). The LLF group was given gemfibrozil 600 mg orally twice daily and HRT group received 2 mg oestradiol in combination with 1 mg norethisterone acetate as a continuous combined therapy once daily. After 3 months, the LLF group added the HRT regimen and patients in the HRT group added gemfibrozil. Hence, all participants received the regimens combined for the last 6 months of the study.

RESULTS

Serum s-cholesterol was markedly decreased in both groups during the first 3 months of single treatment (P<0.0001). This decrease reflected a reduction especially of calculated low density lipoprotein (LDL) s-cholesterol (P<0.001). High density lipoprotein (HDL) s-cholesterol was reduced in the HRT group (P<0.005) but increased (P<0.004) in the LLF group. Triglycerides were also decreased by both treatments but more marked in the LLF group (P<0.0001) than in the HRT group (P<0.02). After 9 months the reduction remained in both groups but no additive effects were encountered in any of the groups.

CONCLUSION

The effects by gemfibrozil on s-cholesterol and triglycerides levels seem to be superior to continuous combined HRT in overweight women with elevated triglycerides. The combination of the two drugs did not seem to offer any additional benefit concerning the routine serum lipid or lipoprotein profile.

A comparison of continuous combined hormone replacement therapy, HMG-CoA reductase inhibitor and combined treatment for the management of hypercholesterolemia in postmenopausal women

OBJECTIVE

To compare the lipid-altering effects of hormone replacement therapy alone and in combination with HMG-CoA reductase inhibitor in postmenopausal women with hypercholesterolemia.

METHODS

This was a prospective randomized controlled trial with 3 parallel groups. The patients (n = 35) were randomly assigned to receive pravastatin 20 mg/day (n = 12); continuous combined hormone replacement therapy (0.625 mg conjugated estrogen/day combined with medroxyprogesterone 5 mg/day) (n = 12); continuous combined hormone replacement therapy plus pravastatin (n = 11) for 16 weeks.

RESULTS

Among patients treated with continuous combined hormone replacement therapy levels of total cholesterol (10.7%) and LDL cholesterol (12.6%) decreased significantly (p < 0.05), while levels of high density lipoprotein cholesterol (5%) and triglycerides (6.2%) increased insignificantly (p > 0.05). Patients in the pravastatin group achieved significant reductions of 18.8 and 21.4% in total cholesterol and low density lipoprotein cholesterol levels, respectively (p < 0.05). Among patients treated with a combination of continuous combined hormone replacement therapy plus pravastatin, levels of total cholesterol (20.5%) and low density lipoprotein cholesterol (23.8%) decreased the most, while levels of triglycerides (2.1%) decreased lower than the pravastatin-only group. The mean percentage of the differences between the baseline and treatment levels of the lipids and lipoproteins were not significant between the 3 study groups (p > 0.05).

CONCLUSION

No significant difference between hormone replacement therapy alone and in combination with HMG-CoA reductase inhibitor in the treatment of postmenopausal women with hypercholesterolemia was noted in this study. The combination of hormone replacement therapy not only does not adversely affect the lipid-lowering effect of pravastatin alone, but hormone replacement therapy also offers additional benefits in the treatment of hypoestrogenic hypercholesterolemia in postmenopausal women.

Effects of postmenopausal hormone replacement therapy on lipid, lipoprotein, and apolipoprotein (a) concentrations: analysis of studies published from 1974-2000

OBJECTIVE

To establish reference estimates of the effects of different hormone replacement therapy (HRT) regimens on lipid and lipoprotein levels.

DESIGN

Review and pooled analysis of prospective studies published up until the year 2000.

SETTING

Clinical trials centers, hospitals, menopause clinics.

PATIENT(S)

Healthy postmenopausal women.

INTERVENTION(S)

Estrogen alone, estrogen plus progestogen, tibolone, or raloxifene in the treatment of menopausal symptoms.

MAIN OUTCOME MEASURE(S)

Serum high- and low-density lipoprotein (HDL and LDL) cholesterol, total cholesterol, triglycerides, and lipoprotein (a).

RESULT(S)

Two-hundred forty-eight studies provided information on the effects of 42 different HRT regimens. All estrogen alone regimens raised HDL cholesterol and lowered LDL and total cholesterol. Oral estrogens raised triglycerides. Transdermal estradiol 17-beta lowered triglycerides. Progestogens had little effect on estrogen-induced reductions in LDL and total cholesterol. Estrogen-induced increases in HDL and triglycerides were opposed according to type of progestogen, in the order from least to greatest effect: dydrogesterone and medrogestone, progesterone, cyproterone acetate, medroxyprogesterone acetate, transdermal norethindrone acetate, norgestrel, and oral norethindrone acetate. Tibolone decreased HDL cholesterol and triglyceride levels. Raloxifene reduced LDL cholesterol levels. In 41 studies of 20 different formulations, HRT generally lowered lipoprotein (a).

CONCLUSION(S)

Route of estrogen administration and type of progestogen determined differential effects of HRT on lipid and lipoprotein levels. Future work will focus on the interpretation of the clinical significance of these changes.