Long-term effects of hormone replacement therapy

Effects of different doses of soy isoflavones on bone tissue of ovariectomized rats

AIM

Studies report that hormone replacement prevents osteoporosis, but there are doubts whether isoflavones are really efficient in this process. The aim of this study was to evaluate the effects of different doses of soy isoflavones on bone tissue of ovariectomized rats.

METHODS

Forty female rats at the age of 6 months were ovariectomized and, after 3 months, the animals were divided into four groups: GI - Control (treated with drug vehicle); GII - treated with isoflavones (80 mg/kg per day); GIII - treated with isoflavones (200 mg/kg per day) and GIV - treated with isoflavones (350 mg/kg per day). Soy isoflavones were administered by gavage for 90 consecutive days. After treatment, the rats were euthanized and their distal femurs were removed for histological routine, histochemistry and biochemical study. Histological sections were stained with hematoxylin-eosin or subjected to picrosirius red and alcian blue methods. Shafts of femurs were submitted to biochemical assay and tibias were subjected to biophysical and biomechanical tests.

RESULTS

In distal femurs, the trabecular bone volume was higher in the groups treated with isoflavones, being higher in GIV, while the cortical bone width and the presence of mature type I collagen fibers were higher in GII. At the trabecular bone region, the percentage of total glycosaminoglycans (GAGs) was higher in GII and the percentage of only sulfated GAGs was higher in GIII, while the higher content of chondroitin sulfate in shafts of femurs was seen in GIV. Biophysical and biomechanical tests in tibias did not differ among the groups.

CONCLUSION

Our data indicate that soy isoflavones improve bone quality in femurs of rats by increasing histomorphometric parameters, the content of GAGs and mature type I collagen fibers. These positive effects are dose-dependent and it was different in cortical and trabecular bone.

Prevention of osteoporosis

<zakljucak> Osteoporoza je generalizovan, progresivan i ireverzibilan proces gubljenja kostane mase sa ostecenjem mikroarhitekture kostanih gredica, pre svega trabekularne kosti, zbog cega kosti postaju lako lomljive. Ispitivanja ukazuju na pretecu epidemiju bolesti u nastupajucim decenijama usled demografskih prome- na, tj., povecanom broju osoba starijih od 65 godina. Prevencijom osteoporoze potrebno je obuhvatiti sve uzraste, osobe oba pola bez procene individualnih faktora rizika. Cilj je da se u svakom zivotnom periodu, na osnovu danasnjih dobro dokumentovanih medicinskih saznanja i cinjenica maksimalno ucini za postizanje i ocuvanje zdrave i cvrste kostane strukture. Kod prevencije osteoporoze bitna su sva tri stupnja: primarni, sekundarni i tercijarni. Oni se po nacinu lecenja preplicu. Terapija mora da bude individualizovana. Socioekonomski faktori igraju bitnu ulogu, kao i nacin ishrane, fizicka aktivnost i genetsko nasledje. Dokazan je pozitivan uticaj estrogena na promene u strukturi kostiju kod zena. Hormonska supstituciona terapija je efektna u prevenciji osteoporoze i dodatno doprinosi kvalitetu zivota, poboljsava kogniciju i odlaze pocetak demencije, smanjuje opseg kolorektalnog karcinoma 51. Veci broj studija pokazao je da se zivotni vek kod zena koje primaju HRT produzava 52, 53. Bitno je da postoji individualizovan pristup prevenciji i terapiji oteoporoze koji se zasniva na zasebnom rizicnom profilu svake zene. Veci broj pitanja koja su vezana za primenu HRT zahtevaju dodatna ispitivanja, kao sto su efekti na centralni nervni sistem, delovanje na kardiovaskularni sistem i na rizik od raka dojke.

Effects of isoflavone and exercise on BMD and fat mass in postmenopausal Japanese women: a 1-year randomized placebo-controlled trial

The combined intervention of isoflavone intake and walking exercise over 1 year in postmenopausal Japanese women exhibited a trend for a greater effect on prevention of bone loss at the total hip and Ward's triangle regions.

INTRODUCTION

The additive effects of isoflavones and exercise on bone and lipid metabolism have been shown in estrogen-deficient animals. In this study, we determined the effects of isoflavone intake, walking exercise, and their interaction on bone, fat mass, and lipid metabolism over 1 year in postmenopausal Japanese women.

MATERIALS AND METHODS

A total of 136 postmenopausal women at <5 years after the onset of menopause were randomly assigned to four groups: (1) placebo, (2) walking (45 minutes/day, 3 days/week) with placebo, (3) isoflavone intake (75 mg of isoflavone conjugates/day), and (4) combination of isoflavone plus walking. BMD, fat mass, serum lipid, and serum and urinary isoflavone concentrations were assessed.

RESULTS

A significant main effect of isoflavone on the reduction in trunk fat mass was obtained at 12 months. Significant main effects of walking on the reduction in fat mass in the whole body and the trunk were observed at 3, 6, and 12 months and that in the legs and arms at 6 and 12 months. Serum high-density lipoprotein (HDL)-cholesterol concentration significantly increased by 12 months after the walking and the combined intervention. After 12 months, a significant main effect of isoflavone on BMD was observed only at Ward's triangle. Walking prevented bone loss at the total hip and the Ward's triangle to significant degrees. The effect of the combined intervention on BMD at total hip and Ward's triangle regions was greater than that of either alone. No significant interaction was observed between isoflavone and walking in any measurements recorded during the study.

CONCLUSIONS

Our study suggest that combined intervention of 75 mg/day of isoflavone intake and walking exercise 3 times/week for 1 year showed a trend for a greater effect on BMD at total hip and Ward's triangle regions than either alone. Intervention with isoflavone in postmenopausal Japanese women showed a modest effect on BMD compared with those in Westerners. Further studies over longer treatment duration that include assessment of BMD at various regions are necessary to ascertain the clinical significance of the combined intervention of isoflavone plus walking in postmenopausal women.

Cooperative effects of isoflavones and exercise on bone and lipid metabolism in postmenopausal Japanese women: a randomized placebo-controlled trial

Cooperative effects of isoflavones and exercise on bone and lipid metabolism have been exhibited in estrogen-deficient animals; however, results from clinical trials have not been published. In this study, we determined the effects of isoflavone intake and walking and their interaction on bone and lipid metabolism in postmenopausal women over 24 weeks. The bioavailability and metabolism of isoflavones (daidzein in particular) were also examined to clarify the mechanism of their bone-protective effects in humans. One hundred twenty-eight subjects were randomly assigned to 4 groups: placebo; placebo combined with walking (3 times per week); isoflavone intake (75 mg of isoflavones conjugates per day); and isoflavone combined with walking. The subjects were classified by equol status (producers or nonproducers) as identified using production of equol from daidzein in fecal culture. Bone mineral density (BMD), body composition, and serum concentrations of isoflavones were assessed. Serum high-density lipoprotein cholesterol concentration significantly increased (6.1%, P = .03), and fat mass in the whole body significantly decreased (-4.3%, P = .0003) from the baseline in the combined intervention group. There were no significant differences in BMD between baseline and postintervention in any of the treatment groups. However, the percent changes in BMD in equol producers were -0.53% and +0.13% in the sub-whole body and total hip, respectively. This was significantly different compared with -1.35 and -1.77 for the sub-whole body and total hip, respectively, in nonproducers in the isoflavone group (P = .049 and .040, respectively). The mean serum equol concentration was significantly higher in equol producers than in nonproducers in the isoflavone groups, but not in the placebo group. The combination of isoflavones and exercise exhibited favorable effects on serum lipid and body composition of postmenopausal women. The findings of this study suggest that the preventive effects of isoflavones on bone loss depend on the individual's intestinal flora for equol production.

Prevalence and correlates of hormonal therapy among Israeli women in the post-WHI era

OBJECTIVES

Following the results of recent randomized controlled trials on the risks and benefits of the long-term use of hormonal therapy (HT), practice guidelines regarding HT use have been revised. The aim of the study is to assess the prevalence and the correlates of HT use in Israel in 2003.

METHODS

This is a cross-sectional study, conducted on a representative sample of the general population in Israel aged 21 years and over. The study questionnaire is based on the European Health Interview Survey (EUROHIS) project, aimed to develop uniform study tools, to enable international comparisons. The current module of the survey focused on women's health, and telephone interviews were conducted with 1396 women by trained interviewers in the year 2003.

RESULTS

Out of a total of 1396 participants, 535 were defined as peri- or postmenopausal (38%). Of them, 9.9% were currently using HT (11.7% and 2.9% among the Jewish and Arab participants, respectively), and their mean age (S.D.) was 57.7 (6.5) years. Mean duration of HT use was 8.0 (5.5) years. Treatment of menopausal symptoms was the most common reason for HT use (69.2%). Significant correlates of HT use were age, being secular and having seen a gynecologist in the previous 12 months.

CONCLUSIONS

Current HT use rates reported are lower than those reported 3 years ago for Israeli women. Awareness of both physicians and patients to the WHI results (2002), may have accounted for this trend, at least partially.

Justification for the use of HRT in the long-term prevention of osteoporosis

Osteoporosis is a common condition in postmenopausal women and is associated with significant healthcare costs, morbidity and mortality. It is clear that long-term hormone replacement therapy (HRT) has a role to play in preventing osteoporosis by increasing bone mineral density and reducing fracture rate. It is important that these benefits, as well as those on climacteric symptoms, quality of life, colorectal carcinoma and cognition, are not underestimated in the face of the postulated risks with regard to breast cancer and cardiovascular disease. In conclusion, HRT should currently be used only for women with climacteric symptoms or an increased risk of osteoporosis, and it is important that there is an individualised approach to treatment based on each woman's risk profile.

Combined intervention of soy isoflavone and moderate exercise prevents body fat elevation and bone loss in ovariectomized mice

Body fat accumulation and bone loss are both often associated with estrogen deficiency following menopause. In this study, we examined whether soy isoflavone, one of the phytoestrogens, and moderate exercise interventions exhibit cooperative effects on body composition and bone mass in ovariectomized (OVX) mice. Eight-week-old female mice were assigned to 6 groups: (1) sham-operated (sham); (2) OVX; (3) OVX with received a soy isoflavone diet (OVX+ISO); (4) OVX with exercised on a treadmill (OVX+EX); (5) OVX with given both isoflavone and exercise (OVX+ISO&EX ); and (6) OVX with treated with 17 beta-estradiol subcutaneously (OVX+E2). Body composition and bone mineral density (BMD) were estimated by dual-energy x-ray absorptiometry (DXA). After the 6-week intervention, whole body fat (%) in the OVX group showed significantly higher than that in the sham group. Intervention of exercise and isoflavone alone partially inhibited OVX-induced body fat gain, and the combined intervention as well as E2 treatment completely restored fat mass to the sham level. Lean body mass in the whole body was not different in OVX group compared with that in OVX+ISO, OVX+EX, and OVX+E2 groups, but it was significantly higher in OVX+ISO&EX than in other groups. BMD of the whole body, lumbar spine, or femur showed significantly reduced by OVX, and the bone loss was partially inhibited by intervention of exercise or isoflavone alone. However, the combined intervention completely restored the bone mass to the level of sham, as did E2. Serum total cholesterol was significantly increased by OVX, which was normalized by the combined intervention or E2 treatment. These results demonstrate that combined intervention of soybean isoflavone and exercise prevented body fat accumulation in the whole body with an increase in lean body mass and restoration of bone mass, and reduced high serum cholesterol in OVX mice.