Last update:
15-Jun-2001

Arch Hellen Med, 17(6), November-December 2000, 600-608

ORIGINAL PAPER

Low dose estradiol valerate plus estriol can preserve bone loss
in the forearm and attenuate climacteric symptoms
in early postmenopausal women

Z. KAMENOV,¹ G. KOLAROV,² M. ORBETZOVA,³ N. AOKI,⁴ M. IMAMURA,⁴
H. HIGASHINO,⁵ M. PROTICH,¹ B. NALBANSKI<sup>2

1</sup>Clinic of Endocrinology, "Aleksandrovska" University Hospital, Medical University, Sofia
²Clinic of Gynecology, "Maichin dom" University Hospital, Medical University, Sofia
³Clinical Centre of Endocrinology and Gerontology, Medical University, Sofia, Bulgaria
⁴Clinic of Endocrinology, 2nd Department of Internal Medicine, Kinki University, School of Medicine, Osaka
⁵Department of Pharmacology, Kinki University, School of Medicine, Osaka, Japan

OBJECTIVE The aim of the study was to establish whether a combination of low dose estradiol valerate (EV) and estriol (E3) is able to alleviate climacteric symptoms and preserve bone in early postmeno-pausal women. METHOD A one-year prospective non-randomized study was conducted of two groups of women: control group (n=31) and hormone replacement therapy (HRT) group (n=35), treated with 1 mg EV and 2 mg E3, combined with sequential levonorgestrel 0.25 mg. The criteria for inclusion were: 9–18 months after last menstrual bleeding, FSH>25 IU/L, moderate climacteric symptoms, bone mineral density (BMD) of less than 2.5 SD below peak adult bone mass. None of the women had any pre-existing medical condition which could affect bone metabolism. BMD was estimated by single-energy X-ray absorptiometry on the distal and ultradistal areas of the forearm at the start of the study and after 1 year. The Kupperman menopausal index (KI), Hamilton anxiety scale (HAMA), and adverse effects were recorded at baseline and at the 3rd, 6th and 12th months. RESULTS No differences in age, height, menstrual history, parity, physical activity, exposure to sunlight, coffee intake, HAMA and distal BMD were observed between the groups. In the control group body mass index (BMI) and ultradistal BMD were higher and KI lower than in the HRT group. During the study KI and HAMA decreased significantly in the HRT group compared to initial values and to the control group. BMD increased significantly in the HRT group for both distal and ultradistal areas while in the control group a significant decrease in these parameters was observed. CONCLUSIONS Treatment with low dose EV+E3 is sufficient to reduce climacteric symptoms and prevent bone loss with acceptable tolerability in early menopause. Key words: Bone mineral density, Early menopause, Hamilton anxiety scale, Hormone replacement therapy, Kupperman menopausal index.

During the early postmenopausal period a number of unfavourable processes take place in the female organism. Adequate treatment could considerably improve the quality of life of postmenopausal women. The unfavourable effects of estrogen deficiency in the clima-
cteric period can be divided into short-, medium- and long-term and comprise neurogenic and psychogenic symptoms. Several methods are now used to measure the severity of the climacteric syndrome. Some of these, as for example, the Kupperman menopausal index (KI),¹ refer predominantly to neurogenic aspects, while others, such as the Hamilton anxiety scale (HAMA),² Selbst-beurteilungs-Depressions-Skala (SDS), profile of mood states (POMS), etc.,³ stress on the psychological changes after menopause. Hormone replacement therapy (HRT) has proved to be effective in alleviating climacteric complaints.^4–6 The early postmenopausal period is also characterized by active bone loss, although this is asymptomatic. Taking control of bone loss could improve the long-term "bone perspective" in females. Estrogens can protect,^7,8 or even increase⁹ bone mass.

Sufficient information has been accumulated concerning the beneficial effects of treatment with standard doses of estrogens, i.e. 0.625 mg conjugated equine estrogens (CCE), 1 mg 17-beta estradiol (E2) oral or 50 μg transdermal, 2 mg estradiol valerate (EV) daily, but the issue of the minimal effective doses of estrogens is still debated. The aim of this study was the estimation of the effect of treatment with a low dose of estrogens combined with progestin in a sequential regimen on bone mineral density (BMD) and on the degree of the expression of climacteric syndrome during the early postmenopausal period.

MATERIAL AND METHOD

A one-year prospective, non-randomized, open study of menopausal outpatients referred to the University Clinics of Gynecology and Endocrinology in Sofia Medical University was performed. The criteria for selection were as follows:

a. Early non-operative postmenopausal period, 9–18 months after the last menstrual period, increased FSH (>25 IU/L), and absence of previous HRT

b. Moderate climacteric syndrome, showing 20–35 points according to the KI

c. Clinical and biochemical data indicating absence of other conditions leading to secondary osteoporosis. Women suffering from diseases which are known to affect mineral metabolism were not included. It was also considered necessary for the selected patients to have had no intake of medicine with osteotropic action throughout the year prior to, and during the study. Patients with osteoporosis showing BMD greater than 2.5 SD below peak adult bone mass¹⁰ on baseline investigation, which requires intensive treatment, and patients with BMD>0 SD were also excluded from the study. To ensure optimal calcium (Ca) intake all women took 600 mg Ca daily in pills during the study. All the women were examined by a gynecologist and a breast specialist. They were briefed on the advantages and the risks of HRT, following which each made her own choice about whether to start HRT or not, and signed an informed consent. The study was approved by the institutional review committee.

In this way, two groups were formed: a control group who received no treatment (n=31) and a treatment (HRT) group (n=35) to whom low doses of estrogens were administered orally in a sequential regimen: 11 days 1 mg EV and 2 mg estriol (E3), followed by 10 days 1 mg EV, 2 mg E3 and 0.25 mg levonorgestrel (Cyclo-Menorette, Wyeth-Lederle). The next course of tablets was started on the 28th day.

The following data were also recorded for each participant: age, height, weight, BMI, duration of time after the last menstrual period, mean interval and mean duration of menstrual cycle during the fertility period, parity, and the number of coffees per day. At the beginning of the study and on the 3rd, 6th and 12th months all women completed a questionnaire covering the 11 symptoms determining KI: hot flushes (with or without sweating), paresthesias, insomnia, nervousness, melancholia, vertigo, fatigue, arthralgia/myalgia, headache, palpitations, and formication. Each symptom was rated on a scale of 0–3 referring to slight, moderate, and severe complaints. To calculate the KI a multiplication factor was used as follows: 4 for hot flushes, 2 for paresthesias, insomnia, and nervousness, and 1 for all other symptoms. A total score of 15–20 indicated mild, 20–35 moderate and over 35 severe climacteric syndrome.¹ Simultaneously, the 14 symptoms of HAMA were recorded, including anxious mood, tension, fear, insomnia, intellectual, depressed mood, somatic (muscular), somatic (sensory), cardiovascular symptoms, respiratory symptoms, gastrointestinal symptoms, genitourinary symptoms, autonomic symptoms, behaviour at interview. The severity of symptoms was assessed using the following scale: 0=not present, 1=mild, 2=moderate, 3=severe. A total score of HAMA up to 14 indicated mild, from 15 to 28 moderate and over 28 severe climacteric complaints.²

Physical activity was estimated by points at the beginning and end of the study:

– Sedentary work-style without additional physical exercise=0 points

– Sedentary work-style with physical exercise during the weekends=1 point

– Sedentary work-style with physical exercise at least 3 days weekly=2 points

– Work-style associated with physical activity and exercise=3 points.

Exposure to sun was also estimated by points:

– Work indoors without exposure to sun=0 points

– Work indoors but residing at the seaside in the summer=1 point

– The same with exposure to sun during the weekends also=2 points

– Work outdoors=3 points.

The BMD was measured by the same investigator at the beginning and at the end of the study on the forearm by single-energy X-ray absorptiometry (densitometer DTX-100-Osteo-meter A/S-Denmark). Calibration with the standard phantom supplied by the producer was performed daily. BMD was recorded on the ulna and radius in g/cm² at the distal area (predominantly compact bone) and the ultradistal area (predominantly cancellous bone).¹¹ The region of measurement is automatically determined proximal and distal to the point at which the radius and ulna are separated by 8 mm. For more details concerning this method see reference 12.

The FSH was measured by the immunoenzyme method using commercial kits (Serozyme, Serono, Switzerland). The intra- and interassay coefficients of variation were 2.5% and 3.8%, respectively.

Women on HRT were followed-up for side effects, breast discomfort, bloating, nausea, headache, intermenstrual bleeding and their dynamics, if present.

On starting treatment the HRT-group numbered 37 women but afterwards two withdrew for reasons not related to the medicine. The control group initially consisted of 40 women but later 9 of them were excluded because of starting sedative therapy, improper compliance, etc.

Statistical analysis was performed using the SPSS 8.0 statistical package. All data are presented as the mean±SEM (standard error of mean). Differences at the beginning, during and at the end of the study period in each group were explored using Student's paired t-test. In the case of non-normally distributed data, the Mann-Whitney U test and Wilcoxon's test were used for unpaired and paired comparisons respectively. Pearson and Kendall correlation coefficients were calculated for relevant variables. Significance was assumed when P<0.05.

RESULTS

No substantial differences between the two groups were observed according to age, height, mean interval and duration of menstrual cycle, parity, number of the cups of coffee consumed daily, physical activity and exposure to the sun at the beginning and the end of the study (tabl. 1). The treatment group initially had a lower BMI.

The initial KI was significantly lower in the control group than is the treatment group (25.8±0.76 vs 29.1±0.58, P<0.01). At the end of the study period it decreased significantly in the controls (P<0.001) compared to the initial data. In the HRT group there was a highly significant decrease (P<0.001) even during the first 3 months and persisting between the 3rd and the 6th months. During the second half-year the KI kept on decreasing, though not reaching a significant difference from the 6th month. The differences between the groups were highly significant (P<0.001) starting from the 3rd month (tabl. 2, fig. 1). A similar pattern was observed concerning the HAMA (tabl. 3, fig. 2). No significant difference was found between the groups at the onset of the study. A significant decrease of the HAMA was observed in the control group (P<0.001) at the end of the study period compared to the initial data. In the treatment group the HAMA score fell significantly starting from the 3rd month (P<0.001) continuing to be low until the 12th month. The intergroup differences reached significance as early as the 3rd month (P<0.001).

The side effects reported in the treatment group are shown on table 4. Sixteen women (46%) had acceptable side effects (some of them more than one) on the 3rd month which did not present a sufficient argument for discontinuation of the treatment and their number had decreased to 3 (8.6%) by the end of the study. Thus, on the 12th month only 2 women reported 1 adverse effect and 1 woman had two. No overt climacteric symptoms occurred during the 7-day drug free period.

Initially there was no significant difference in BMD at the distal area between both groups (tabl. 5). Throughout the study a 1.6±0.23% decrease was established in the control group whereas in the treatment group distal BMD increased by 0.6±0.15% (fig. 3). The BMD dynamics were more pronounced in the ultradistal part. Initially the BMD was substantially lower in the treatment group than in the control group, but it rose significantly by 1.9±0.41% in the course of the treatment, while in the control group it diminished considerably by 3.4± 0.23% (P<0.001) (tabl. 5, fig. 3).

Correlation coefficients of the main initial parameters in all women participating in this study are shown on table 6. A highly significant positive correlation between KI and HAMA at the beginning of the study (r=0.69) as well as during the whole study period in both groups was observed. The percentage decrease of KI and HAMA at the end of the study was also significantly correlated (r=0.94 in the HRT group; r=0.80 in the control group). The distal and ultradistal BMD were also significantly correlated with physical activity (r=0.34; r=0.37, respectively) and exposure to sunlight (r=0.33; r=0.39, respectively). During the treatment a significant positive correlation was established between the percentage increase in ultradistal BMD and the percentage decrease of KI (r=0.59) and HAMA (r=0.56). The increase in distal BMD was not significantly correlated with the above variables.

DISCUSSION

This study was designed to answer the question whether the combination of low doses of estrogens with progestin in a sequential regimen with a drug free interval, started in the early postmenopausal period, is able to diminish climacteric symptoms and arrest bone loss.

The doses (minimal-effective, optimal, etc.) and the time to start treatment of neurogenic and psychological symptoms in order to reach an optimal benefit/risk ratio are still under discussion.^13–15 As in our study, a good effect from treatment with low doses of estrogens in women with moderately expressed climacteric syndrome was also established by Maclennan et al,¹⁶ and others.^17,18 Gangar et al reported abolishment of menopausal symptoms after continuous administration of 1 mg EV+5 mg medroxyprogesterone acetate daily in patients treated with GnRH analogues.¹⁹ Although considered a "weak" estrogen, E3 has proved its favorable effect on symptoms caused by urogenital atrophy²⁰ and on other menopausal complaints.^21,22 In some cases E3 is preferred because of its safety.²³

Initially in this study the women who preferred to start HRT had significantly more marked neurological complaints as estimated by the KI and they displayed a trend towards more severe symptoms as indicated by the HAMA. The women in the control group generally showed spontaneous alleviation of the reported symptoms in the course of the study. After 1 year some of the control women failed to improve while in others the complaints had diminished considerably. In the treatment group the most pronounced improvement was reached during the first 3 months and this beneficial effect persisted till the end of the study. The percentage change in KI between the beginning and the end of the study was 20.3±1.02% in the control group and 65.4±2.25% in the HRT group. These data are similar to the results obtained by Marslew et al after the first year of treatment. In a two-year placebo-controlled study this group administered 2 mg EV continuously, combined with 1 mg cyproteron acetate continuously or with sequential levo-norgestrel 75 μg, and achieved a reduction in KI of 72% and 78% respectively. In the placebo group the change was 19%. They found no difference between the two treatment regimens in reducing menopausal symptoms. The initial KI of their patients was lower than that of the groups in this study, perhaps because of the longer postmenopausal period (6 months to 3 years) before initiation of treatment.²⁴

Summarising the results of numerous studies it may be concluded that the yearly postmenopausal loss of bone mass ranges between 1% and 10%, 2–3% on the average, and it is more marked during the first years and in the cancellous bone.^25,26 The administration of HRT results, according to some authors,^27,28 in a 5–7% increase of bone mass in the space of 12 to 18 months, followed by a plateau. Other authors find no difference in bone density throughout the treatment period and some report a decrease.²⁹ These differences may be related to various factors, including the continuation and the scheme of treatment, the hormone and the dose applied, the site of measurement, ethnic and geographical factors, etc.

The various studies have not yet solved the problem of the minimal estrogen dose required to preserve bone. It is accepted that the minimum effective dose with osteoprotective effect for CEE is 0.625 mg, for E2 1 mg oral, 50 μg transdermal and for EV 2 mg daily.^30,31 The report of Εttinger et al,³² and more recent studies^33,34 showed that a dose of 0.3 mg CEE daily protects bone as does 0.625 μg if adequate calcium intake is available. Edmonds established significant reduction in bone loss during GnRH analogue treatment when a 25 μg E2 patch is applied.³⁵ Evans and Davie found no difference between the bone preserving effect of low (25 μg) and standard (50 μg) doses of transdermal E2 after 3 years of treatment.³⁶ There is scanty information concerning the effect of low-dose EV on bone. Duursma et al in a 3.7-year study compared the effect of 1 mg EV daily to 0.625 mg CCE by using dual photon absorptiometry.³⁷

Data about the effect of E3 on bone are contradictory. Lindsay et al³⁸ and recently Hart et al, and Devogelaer et al^39,40 failed to establish any efficacy of the E3 treatment (1 and 2 mg respectively). Lately some Ja-panese centres have reported a powerful osteoprotective action of E3 in a dosage 2 mg daily cyclically or continuously. By using dual energy X-ray absorptiometry Nozaki et al⁴¹ and Minaguchi et al²² showed a significant increase of 1.66% and 1.79% respectively in the spine and a corresponding decrease in biochemical markers after an 1-year treatment of initially osteopenic women, coupled with improvement in KI and good tolerability. Itoi et al found a bone-preserving effect of E3 comparable to 0.625 CEE in early postmenopausal women after 2 years of treatment.⁴² Nishibe et al in a 10-month study involving 29 women aged 70–84 years established that E3 is effective against senile osteoporosis, and low-turnover bones in elderly women are also responsive to E3.⁴³ Other studies (H. Mitsuhashi-unpublished data) also support a beneficial effect of E3 in Japanese women. According to the above data a speculative conclusion could be made about race differences in E3 action. In this study, 1 mg EV plus 2 mg E3 administered cyclically blocked early postmenopausal bone loss, measured on the forearm in Caucasian women.

The early postmenopausal period is of particular interest because it marks the highest rate of bone loss, although activation of bone turnover starts in the premenopausal period.⁴⁴ The study showed a decrease in BMD in the control group which was statistically more marked in the cancellous bone, 3.4%, whereas in the treatment group BMD increased significantly by 1.9%. This can be related to more active role of trabecular bone in maintaining calcium balance which is well-known.⁴⁵ Gambacciani et al, investigating bone density of the distal radius with dual-photon absorptiometry in the early postmenopausal period (6–12 months after the last bleeding) found a 4.6% loss in the control group and a 4.2% increase in group treated with 50 μg E2 transdermally after an 1-year follow-up.⁴⁶ Other authors⁴⁷ report a less severe bone loss per year on the distal forearm after the menopause, 2% in controls and 0.5% in patients treated with conventional doses of oral estrogens.

This study established a positive correlation between BMD and BMI, stature, physical activity and exposure to sunlight, and a negative correlation between BMD and both FSH levels and menopausal KI and HAMA scores (tabl. 6). Short stature, low BMI, insufficient physical activity and sunlight are well known risk factors for osteoporosis.¹⁰ In obese women there is a beneficial effect of the even small quantity of estron generated from supra-renal steroids in the fatty tissue. This, in addition to the higher mechanical load on the skeleton, is of substantial importance for women with higher BMI. Bone loss has been shown to correlate positively with climacteric symptoms⁴⁸ and FSH⁴⁹ and this study confirmed these data. During the treatment the increase in BMD in more metabolically active cancellous bone was correlated with fast improvement in climacteric symptoms.

The sum effect of the treatment in this study cannot be precisely estimated because of the non-random pa-tient selection, but the positive change of BMD in treated patients implies a marked favorable effect. Adverse effects during the study period were mild and temporary, and did not cause its discontinuation.

In conclusion, treatment with 1 mg EV combined with 2 mg E3 and 0.25 mg levonorgestrel is sufficient to reduce the climacteric symptoms and prevent bone loss with acceptable tolerability in early postmenopausal wo-men. Longer, prospective and randomised studies are necessary to determine the long-term efficacy of this treatment as well as its potency in osteoporotic patients.

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