Does tibolone affect serum leptin levels and body weight in postmenopausal women?

Is there evidence that estrogen therapy promotes weight maintenance via effects on leptin?

OBJECTIVE

Leptin, a hormone secreted by adipocytes, plays a crucial role in regulating energy balance. Estrogen, like leptin, reduces food intake and adiposity while increasing energy expenditure in animals and humans of both sexes through its actions on the central nervous system. We reviewed the literature for studies of the effects of exogenously administered estrogen on serum leptin concentrations and adiposity in women.

METHODS

Using PubMed/Medline, we searched for studies of hormone therapy that enrolled healthy postmenopausal women. Studies were further evaluated to determine if leptin and adiposity were monitored both at baseline and throughout a treatment period of at least 2 months.

RESULTS

Twenty articles met inclusion criteria. We found no consistent effects of exogenous estrogen on serum leptin concentrations, adiposity, or weight gain.

CONCLUSIONS

Despite suggestive data from animal studies, the current literature does not provide compelling evidence that estrogen therapy attenuates weight gain, alters circulating leptin levels, or improves leptin action in postmenopausal women.

Early menopause association with employment, smoking, divorced marital status and low leptin levels

AIMS

The aims of this study were (1) to investigate the determining risk factors related to early menopause and (2) to compare the relationships between demographic characteristics and hormonal status and leptin levels in subjects with early (no surgical) and natural menopause.

STUDY DESIGN

The prospective study was conducted on 500 women with early and 2700 women with natural menopause. Detailed information was collected about their employment status, past and present smoking habits, coffee and alcohol use, educational level and other factors relevant to health. Thirty participants with early menopause and 30 participants with natural menopause were evaluated for hormone and leptin levels.

RESULTS

Employment status (OR: 1.94), current smoking (OR: 1.80) and divorced marital status (OR: 1.79) were found to be significant risk factors for early menopause. Mean levels of leptin in natural and early menopause were measured 11.40 ± 4.1 ng/ml and 8.01 ± 3.9 ng/ml, respectively (p = 0001). Leptin levels in the early (r = 0.765, p = 0.001) and natural (r = 0.750, p = 0.001) menopause subjects correlated positively with oestradiol (E2) levels.

CONCLUSION

This study shows that early onset of menopause is correlated with smoking, employment status, divorced marital status and lower leptin levels.

Effects of tibolone on abdominal subcutaneous fat, serum leptin levels, and anthropometric indices: a 6-month, prospective, randomized, placebo-controlled, double-blind study

This study was undertaken to evaluate the effects of tibolone on abdominal subcutaneous fat, serum leptin levels (SLLs), and anthropometric indices, and to investigate potential relationships between SLLs, subcutaneous abdominal fat thickness, and anthropometric indices in postmenopausal women. In a 6-mo, prospective, randomized, double-blind, placebo-controlled study, 40 healthy postmenopausal women aged 42 to 67 y (mean: 50+/-4.7 y) were randomly assigned to 1 of 2 groups; during a 6-mo treatment period, the first group received tibolone (Livial tablet; Organon, The Netherlands; 2.5 mg/d; n=19) and the other group was given placebo (n=21). Fasting SLLs determined by enzyme-linked immunosorbent assay, subcutaneous abdominal fat thickness assessed by ultrasound, and anthropometric indices of body weight, body mass index, waist and hip circumference, and waist-to-hip ratio (WHR) were recorded at the beginning and the end of the study. Statistical analyses were performed with Mann-Whitney, Wilcoxon, and Spearman tests. P values <.05 were considered significant. No significant differences between the 2 groups were reported in terms of all baseline characteristics. After 6 mo, body weight (+0.77+/-0.43 kg) and SLLs (+14.7+/-6.4 ng/mL) increased in the placebo control group, whereas waist circumference (-2.6+/-3.0 cm), hip circumference (-3.6+/-3.5 cm), and subcutaneous abdominal fat thickness (-4.3+/-4.8 cm) decreased significantly in the tibolone group (P<.05). At the end of the study, group comparisons revealed significant differences in waist and hip circumference and subcutaneous abdominal fat thickness (P<.05). At baseline, SLLs were correlated with subcutaneous abdominal fat thickness and all anthropometric indices except WHR (P<.05). Subcutaneous abdominal fat thickness was also highly correlated with all indices except WHR (P<.0001). Tibolone was found to decrease waist and hip circumference, as well as subcutaneous abdominal fat thickness. Also, tibolone appeared to attenuate weight gain and leptin increase. SLLs and subcutaneous abdominal fat thickness were positively correlated with all anthropometric indices except WHR.

Serum leptin levels and body composition in postmenopausal women treated with tibolone and raloxifene

OBJECTIVE

To compare body composition and serum leptin levels in untreated postmenopausal women and postmenopausal women treated with tibolone or raloxifene.

DESIGN

This was a prospective, randomized, controlled study. Sixty-eight postmenopausal women were randomized to receive either no treatment (group A, n = 21) or tibolone 2.5 mg/day (group B; n = 23) or raloxifene 60 mg/day (group C; n = 24). All women underwent height, weight, body mass index evaluation and dual energy x-ray absorptiometry determination of body composition at the beginning of the study and after 12 months. Serum leptin levels were determined at the beginning of the study and after 1, 3, 6, and 12 months in all groups.

RESULTS

Women in group A showed no significant changes in both fat and lean mass of arms and legs, whereas a significant increase in trunk fat mass, total fat mass, total percentage of body fat, and trunk percentage of fat was detected 1 year after the beginning of the study. After 12 months, the total percentage of fat mass was significantly higher in group A compared with group B, and the trunk percentage of fat mass was significantly higher in group A compared with groups. In subjects in groups B and C, after 1 year, fat mass, both total and at all areas evaluated, did not show any significant change compared with baseline values. In subjects in group B, total lean and lean mass of the trunk and legs increased significantly at the end of the study, whereas no significant changes were observed in lean mass, total and at all areas evaluated in subjects in group C. After 12 months, total lean mass and lean mass of the legs were significantly higher in group B compared with the other groups. In group A, serum leptin levels were significantly increased at the end of the study compared with baseline values. Leptin concentrations were significantly higher in group A compared with groups B and C after 6 and 12 months. No significant change in serum leptin levels in subjects in groups B and C was detected throughout the study. Serum leptin levels showed a positive, significant correlation with all body composition parameters and body mass index in all groups at the beginning and at the end of the study.

CONCLUSIONS

The present study confirms that postmenopausal hypoestrogenism leads to increased fat content and serum leptin levels. Raloxifene and tibolone seem to prevent postmenopausal body composition changes without significant modifications of serum leptin levels.

Serum leptin concentrations in pre- and postmenopausal women on sex hormone therapy

AIM

The aim of the present study was to investigate the influence of endogenous estradiol and estrogen and estrogen-progestin therapies on concentration in pre- and postmenopausal women.

MATERIALS AND METHODS

The study groups consisted of 26 women with surgical menopause (mean+/-standard deviation (SD): age 51.8+/-2.6 years, body mass index (BMI) 26.45+/-4.56 kg/m(2)), 54 with natural menopause (mean+/-SD: age 50.5+/-3.0 years, BMI 25.75+/-4.09 kg/m(2)) and 40 premenopausal controls (mean+/-SD: age 48.3+/-2.3 years, BMI 26.23+/-4.12 kg/m(2)). The group with surgical menopause received estradiol transdermally (50 microg/day) and those with natural menopause received additionally medroxyprogesterone acetate (5 mg/day) for the last 12 days of the cycle. Before and after 4 months of therapy, body weight, waist and hip circumferences and blood pressure were measured, and BMI and waist-to-hip ratio (WHR) were calculated. Serum leptin, follicle-stimulating hormone (FSH), estradiol (E(2)), testosterone, prolactin and dehydroepiandrosterone sulfate (DHEAS) were measured prior to and after treatment.

RESULTS

Leptin concentrations did not differ statistically among the groups. No correlations between leptin and E(2), FSH, prolactin, testosterone and DHEAS concentrations were found in any of the groups before and after treatment. Leptin level correlated positively with body mass, BMI and hip and waist circumferences in all groups. There were no correlations between leptin and WHR in the pre- and postmenopausal groups. In the premenopausal group and in some postmenopausal groups, serum leptin level correlated with blood pressure.

CONCLUSIONS

Endogenous E(2) and androgens in premenopausal women and estrogen and estrogen-progestin therapies in postmenopausal subjects do not influence serum leptin concentrations. Leptin level is related to body mass and BMI, but not to sex hormone status. The distribution of adipose tissue and the type of obesity (android or gynoid) have no influence on serum leptin concentration. The correlation between serum leptin level and blood pressure requires further investigation.