Changes in body composition in women treated with gonadotropin-releasing hormone agonists

Body composition and cardiometabolic health across the menopause transition

Every year, 2 million women reach menopause in the United States, and they may spend 40% or more of their life in a postmenopausal state. In the years immediately preceding menopause-known as the menopause transition (or perimenopause)-changes in hormones and body composition increase a woman's overall cardiometabolic risk. In this narrative review, we summarize the changes in weight, body composition, and body fat distribution, as well as the changes in energy intake, energy expenditure, and other cardiometabolic risk factors (lipid profile, glucose metabolism, sleep health, and vascular function), that occur during the menopause transition. We also discuss the benefits of lifestyle interventions in women in the earlier stages of menopause before these detrimental changes occur. Finally, we discuss how to include perimenopausal women in research studies so that women across the life-span are adequately represented.

A Randomized Controlled Trial of Ovarian Suppression in Premenopausal Women: No Change in Free-Living Energy Expenditure

OBJECTIVE

The purpose of this study was to determine whether suppression of ovarian function (gonadotropin-releasing hormone agonist [GnRH_AG ]) for 24 weeks in premenopausal women approaching menopause causes changes in body composition and a decline in free-living physical activity energy expenditure (PAEE) and whether endurance exercise training attenuates the changes.

METHODS

Premenopausal women who were approaching menopause (mean [SD]: age 46 [3] years, BMI 26.3 [4.8] kg/m² ) were randomized to 24 weeks of GnRH_AG (n = 14), GnRH_AG + Exercise (n = 11), or placebo (n = 9). Endurance exercise was performed 4 days per week with the goal of expending 200 to 300 kcal per session. Primary outcome measurements included body composition by dual-energy x-ray absorptiometry, total daily energy expenditure (TDEE), and PAEE by doubly labeled water, and resting energy expenditure (REE) by indirect calorimetry.

RESULTS

Changes in TDEE, PAEE, REE, or body composition were not different between groups. However, within the GnRH_AG group, fat mass increased (mean [SE]: total 1.7 [0.4] kg, trunk 0.9 [0.2] kg, leg 0.6 [0.2] kg) and fat-free leg mass decreased (mean [SE]: -0.4 [0.2] kg) significantly.

CONCLUSIONS

In premenopausal women approaching menopause, ovarian hormone suppression resulted in increased adiposity without alterations in TDEE, PAEE, or REE.

Appendicular lean mass is lower in late compared with early perimenopausal women: potential role of FSH

Age-related declines in skeletal muscle mass (i.e., sarcopenia) contribute to physical disability in older women. Although a menopause-related increase in fat mass is well documented, whether menopause influences muscle mass and sarcopenia is unclear. We determined the extent to which skeletal muscle mass differs across the stages of the menopause transition in women and whether these differences are associated with estradiol or other sex hormones. This was a cross-sectional study of 144 healthy women (aged 30-70 yr) classified as premenopausal [n = 30, 38 ± 6 yr (means ± SD)], early (n = 31, 50 ± 3 yr) and late (n = 30, 50 ± 4 yr) perimenopausal, and early (n = 26, 55 ± 3 yr) and late (n = 27, 62 ± 4 yr) postmenopausal. Appendicular lean mass (ALM) adjusted by the square of height in meters (ALM index; ALMi) was assessed by dual-energy X-ray absorptiometry. ALMi was lower (P < 0.05) in late perimenopausal and postmenopausal compared with early perimenopausal, with no significant differences between other groups (premenopausal 6.6 ± 0.6, early perimenopausal 6.8 ± 0.8, late perimenopausal 6.1 ± 0.8, early postmenopausal 6.5 ± 1.1, and late postmenopausal 6.2 ± 0.9 kg/m²). The prevalence of sarcopenia (ALMi ≤ 5.67 kg/m²) was 7%, 3%, 30%, 27%, and 32% in premenopausal, early and late perimenopausal, and early and late postmenopausal groups, respectively. ALMi measured across menopause stages was inversely correlated to follicle-stimulating hormone (FSH; r = -0.28, P = 0.003) but not to estradiol (r = 0.088, P = 0.34). The menopause transition appears to be a vulnerable period for the loss of skeletal muscle mass that may begin during the late perimenopausal transition. Future studies are necessary to investigate the potential effect of FSH on skeletal muscle.NEW & NOTEWORTHY Our data suggest that the late perimenopausal stage may be a vulnerable period for the loss of skeletal muscle, potentially related to elevations in FSH.

Influence of Estradiol Status on Physical Activity in Premenopausal Women

PURPOSE

This study aimed to determine the effects of 5 months of ovarian hormone suppression in premenopausal women on objectively measured physical activity (PA).

METHODS

Participants (age, 35 ± 8 yr; body mass index, 27 ± 6 kg·m) received monthly intramuscular injections of gonadotropin-releasing hormone agonist (GnRHAG) therapy, which suppresses pituitary gonadotropins and results in suppression of ovarian sex hormones. Women were randomized to receive concurrent transdermal E2 (GnRHAG + E2; n = 30) or placebo (GnRHAG + PL, n = 31). PA was assessed for 1 wk before and during each month of the 5-month intervention using a hip-worn accelerometer (Actical, Mini Mitter Co., Inc., Bend, OR). Estimates of time spent in sedentary, light, and moderate-to-vigorous PA (MVPA) were derived using a previously published equation. Subsets of participants in each group were also randomized to a supervised progressive resistance exercise training program.

RESULTS

Total MVPA tended toward being higher (P = 0.08) in the GnRHAG + E2 group at month 4. There were no significant effects of intervention or time in sedentary or light PA. In the subset of women who did not participate in structured exercise training for which Actical data were obtained (n = 16 in each group), total MVPA was higher at month 4 (P = 0.01).

CONCLUSIONS

PA levels seem to be maintained at a higher level in women undergoing pharmacological suppression of ovarian function with E2 add-back when compared with women treated with placebo. These data provide proof-of-concept data that E2 contributes to the regulation of PA in humans. However, given the exploratory nature of this study, future confirmatory investigations will be necessary.

Modulation of Energy Expenditure by Estrogens and Exercise in Women

Reducing estrogen in women results in decreases in energy expenditure, but the mechanism(s) remain largely unknown. We postulate that the loss of estrogens in women is associated with increased accumulation of bone marrow-derived adipocytes in white adipose tissue, decreased activity of brown adipose tissue, and reduced levels of physical activity. Regular exercise may counteract the effects of estrogen deficiency.

Body composition and bone mineral density after ovarian hormone suppression with or without estradiol treatment

OBJECTIVE

Suppression of ovarian hormones in premenopausal women on gonadotropin-releasing hormone agonist (GnRH(AG)) therapy can cause fat mass (FM) gain and fat-free mass (FFM) loss. Whether this is specifically caused by a decline in serum estradiol (E2) is unknown. This study aims to evaluate the effects of GnRH(AG) with placebo (PL) or E2 add-back therapy on FM, FFM, and bone mineral density (BMD). Our exploratory aim was to evaluate the effects of resistance exercise training on body composition during the drug intervention.

METHODS

Seventy healthy premenopausal women underwent 5 months of GnRH(AG) therapy and were randomized to receive transdermal E2 (GnRH(AG) + E2, n = 35) or PL (GnRH(AG) + PL, n = 35) add-back therapy. As part of our exploratory aim to evaluate whether exercise can minimize the effects of hormone suppression, some women within each drug arm were randomized to undergo a resistance exercise program (GnRH(AG) + E2 + Ex, n = 12; GnRH(AG) + PL + Ex, n = 12).

RESULTS

The groups did not differ in mean (SD) age (36 [8] and 35 [9] y) or mean (SD) body mass index (both 28 [6] kg/m). FFM declined in response to GnRH(AG) + PL (mean, -0.6 kg; 95% CI, -1.0 to -0.3) but not in response to GnRH(AG) + E2 (mean, 0.3 kg; 95% CI, -0.2 to 0.8) or GnRH(AG) + PL + Ex (mean, 0.1 kg; 95% CI, -0.6 to 0.7). Although FM did not change in either group, visceral fat area increased in response to GnRH(AG) + PL but not in response to GnRH(AG) + E2. GnRH(AG) + PL induced a decrease in BMD at the lumbar spine and proximal femur that was prevented by E2. Preliminary data suggest that exercise may have favorable effects on FM, FFM, and hip BMD.

CONCLUSIONS

Suppression of ovarian E2 results in loss of bone and FFM and expansion of abdominal adipose depots. Failure of hormone suppression to increase total FM conflicts with previous studies of the effects of GnRH(AG). Further research is necessary to understand the role of estrogen in energy balance regulation and fat distribution.

Regulation of energy expenditure by estradiol in premenopausal women

Suppressing sex hormones in women for 1 wk reduces resting energy expenditure (REE). The effects of more chronic suppression on REE and other components of total energy expenditure (TEE), and whether the reduction in REE is specifically due to loss of estradiol (E2), are not known. We compared the effects of 5 mo of sex hormone suppression (gonadotropin releasing hormone agonist therapy, GnRHAG) with placebo (PL) or E2 add-back therapy on REE and the components of TEE. Premenopausal women received GnRHAG (leuprolide acetate 3.75 mg/mo) and were randomized to receive transdermal therapy that was either E2 (0.075 mg/d; n = 24; means ± SD, aged = 37 ± 8 yr, BMI = 27.3 ± 6.2 kg/m(2)) or placebo (n = 21; aged = 34 ± 9 yr, BMI = 26.8 ± 6.2 kg/m(2)). REE was measured by using a metabolic cart, and TEE, sleep EE (SEE), exercise EE (ExEE, 2 × 30 min bench stepping), non-Ex EE (NExEE), and the thermic effect of feeding (TEF) were measured by using whole room indirect calorimetry. REE decreased in GnRHAG+PL [mean (95% CI), -54 (-98, -15) kcal/d], but not GnRHAG+E2 [+6 (-33, +45) kcal/d] (difference in between-group changes, P < 0.05). TEE decreased in GnRHAG+PL [-128 (-214, -41) kcal/d] and GnRHAG+E2 [-96 (-159, -32) kcal/d], with no significant difference in between-group changes (P = 0.55). SEE decreased similarly in both GnRHAG+PL [-0.07 (-0.12, -0.03) kcal/min] and GnRHAG+E2 [-0.07 (-0.12, -0.02) kcal/min]. ExEE decreased in GnRHAG+PL [-0.46 (-0.79, -0.13) kcal/min], but not GnRHAG+E2 [-0.30 (-0.65, +0.06) kcal/min]. There were no changes in TEF or NExEE in either group. In summary, chronic pharmacologic suppression of sex hormones reduced REE and this was prevented by E2 therapy.

Regulation of Body Composition and Bioenergetics by Estrogens

Evidence points to an important role of estradiol (E2) in the regulation of body composition and bioenergetics. Basic and preclinical research shows that the disruption of E2 signaling through either genetic manipulation or surgical intervention accelerates fat accumulation, with a disproportionate increase in abdominal fat. Clinical evidence for the regulation of body composition and bioenergetics by E2 is less consistent. Evidence exists both for and against menopause as the mediator of changes in body composition. Thus, a need remains to better understand the metabolic actions of estrogens in women and the potential impact on health after the menopause.

Estrogen or raloxifene during postmenopausal weight loss: adiposity and cardiometabolic outcomes

OBJECTIVE

Estrogen-based hormone therapy (HT) attenuates abdominal fat gain after menopause, but whether HT improves abdominal fat loss during weight loss is unknown. It was hypothesized that HT or a selective estrogen receptor modulator (raloxifene) would augment reductions in abdominal visceral fat during weight loss when compared to placebo, potentially increasing improvements in glucose tolerance and lipid profile.

METHODS

Healthy postmenopausal women (n = 119; age 50-70 yr) underwent a 6-month weight-loss (primarily exercise) intervention with randomization to raloxifene (60 mg/d), HT (conjugated estrogens, 0.625 mg/d), or placebo. Outcomes were change in total and abdominal (visceral and subcutaneous) fat mass, lipid profile, and fasting and post-challenge glucose and insulin.

RESULTS

Neither HT nor raloxifene augmented loss of total or abdominal fat mass during exercise-induced weight loss when compared with placebo. Weight loss-induced improvements in risk factors were similar among the three groups, except for a greater reduction in fasted glucose in the HT group (difference in change [95%CI] from placebo; -0.40 [-0.76, -0.05]) and greater reductions in LDL (-0.36 [-0.63, -0.09]) and increases in HDL (0.15 [0.07, 0.24]) in both treatment groups.

CONCLUSIONS

Postmenopausal HT and raloxifene did not increase abdominal fat loss during weight loss, but did improve some cardiometabolic outcomes.

Estrogen: a master regulator of bioenergetic systems in the brain and body

Estrogen is a fundamental regulator of the metabolic system of the female brain and body. Within the brain, estrogen regulates glucose transport, aerobic glycolysis, and mitochondrial function to generate ATP. In the body, estrogen protects against adiposity, insulin resistance, and type II diabetes, and regulates energy intake and expenditure. During menopause, decline in circulating estrogen is coincident with decline in brain bioenergetics and shift towards a metabolically compromised phenotype. Compensatory bioenergetic adaptations, or lack thereof, to estrogen loss could determine risk of late-onset Alzheimer's disease. Estrogen coordinates brain and body metabolism, such that peripheral metabolic state can indicate bioenergetic status of the brain. By generating biomarker profiles that encompass peripheral metabolic changes occurring with menopause, individual risk profiles for decreased brain bioenergetics and cognitive decline can be created. Biomarker profiles could identify women at risk while also serving as indicators of efficacy of hormone therapy or other preventative interventions.

Vascular and metabolic effects of sex steroids: new insights into clinical trials

The early discontinuation of the Women's Health Initiative trials of daily conjugated estrogens and medroxyprogesterone and of conjugated estrogens only was hailed as the "death to the use of hormone replacement regimens" in menopause. The analyses showed risks outweighing benefits of hormone therapy when given broadly to postmenopausal women. The expanding basic science and clinical research on the specific actions of sex steroids at the genomic and nongenomic level, however, shed new insight into these results. This review focuses on the vascular and metabolic effects of sex steroids to illustrate new advances. Understanding the mechanisms of sex steroid receptor action in a tissue-specific manner, ligand-specific dose responses, and the effects of steroid hormones in normal compared to diseased tissues may explain some of the outcomes in the clinical trials. Further research will clarify the potential benefits and risks of hormone therapy after menopause, both in individual patients and in selected populations.

Acute modulation of adipose tissue lipolysis by intravenous estrogens

OBJECTIVE

The aim of this study was to determine whether intravenous (IV) conjugated estrogens (EST) acutely enhance the suppression of whole-body or regional subcutaneous adipose tissue (SAT) lipolysis by insulin in postmenopausal women.

RESEARCH METHODS AND PROCEDURES

We assessed whole-body lipolysis by [(2)H(5)]glycerol rate of appearance (Glyc(RA)) and abdominal and femoral SAT lipolysis (interstitial glycerol; Glyc(IS)) by subcutaneous microdialysis. Postmenopausal women (n = 12) were studied on two occasions, with IV EST or saline control (CON), under basal conditions and during a 3-stage (4, 8, and 40 mU/m(2)/min) hyperinsulinemic, euglycemic clamp. Ethanol outflow/inflow ratio and recovery of [(13)C]glycerol during microdialysis were used to assess blood flow changes and interstitial glycerol concentrations, respectively.

RESULTS

Compared with CON, EST did not affect systemic basal or insulin-mediated suppression of lipolysis (Glyc(RA)) or SAT nutritive blood flow. Basal Glyc(IS) in SAT was reduced on the EST day. However, insulin-mediated suppression of lipolysis in SAT was not significantly influenced by EST.

DISCUSSION

These findings suggest that estrogens acutely reduce basal lipolysis in SAT through an unknown mechanism but do not alter whole-body or SAT suppression of lipolysis by insulin.

Sex hormone suppression reduces resting energy expenditure and {beta}-adrenergic support of resting energy expenditure

Resting energy expenditure (REE) decreases with aging and may decrease in women as a result of the menopause, potentially contributing to weight gain. REE has been observed to fluctuate during the menstrual cycle, suggesting regulation by sex hormones. The aim of the present study was to determine the effects of suppressing estrogen and progesterone on REE. Fourteen premenopausal women, 29 +/- 5 yr old (mean +/- sd), were studied in the midluteal menstrual phase (ML) and after 6 d of GnRH antagonist therapy (GnRHant) administered in the follicular menstrual phase. REE was measured by indirect calorimetry in the morning after a 12-h fast and again during beta-adrenergic blockade to determine sympathetic nervous system (SNS) support of REE. Treatment with GnRHant significantly decreased REE (1405 +/- 42 vs. 1334 +/- 36 kcal/d, mean +/- se, ML vs. GnRHant; P = 0.002). Additionally, SNS blockade tended to alter REE more during ML than during GnRHant (-19 +/- 10 vs. 5 +/- 11 kcal/d; P = 0.14). Suppression of sex hormones to postmenopausal levels by GnRHant reduced REE in young healthy women. These findings suggest that the withdrawal of estrogen and/or progesterone attenuates REE, possibly through a SNS-mediated mechanism.

Precedence of bone loss over changes in body composition and body fat distribution within a few years after menopause

OBJECTIVE

The present study investigated the sequence of certain phenomena with a few years after menopause: bone mineral loss, decrease in lean body mass, increase in body fat mass, or the shift toward upper body fat distribution.

METHODS

Subjects were 64 postmenopausal women aged 50-53 years with right side dominance (mean age+/-S.D., 51.4+/-1.1 years), and 59 age-matched regularly menstruating premenopausal women (51.7+/-1.2 years) serving as controls. Height, weight, body mass index (BMI, wt./ht.(2)), age at menopause (in postmenopausal women), and years since menopause (YSM) were recorded. Anthropometries, bone mineral density (BMD), and body fat distribution were assessed by dual-energy X-ray absorptiometry.

RESULTS

Age at menopause and YSM in postmenopausal women were 51.7+/-1.2 and 2.3+/-1.7 years, respectively. Age, height, weight, BMI did not differ between the two groups. BMD of the bilateral arm, lumbar spine (L2-4), pelvis, and total body were significantly lower in postmenopausal women. However, leg BMD, trunk-leg fat ratio, body fat mass, and the lean body mass did not differ between the two groups.

CONCLUSION

Within a few years after menopause, bone mineral loss precedes lean mass loss, increase in body fat mass, and a shift toward upper body fat distribution. We can say that bone tissue is more sensitive to hypogonadism than lean and fat tissues are.

Changes in serum leptin levels during GnRH agonist therapy

The purpose of the present study was to investigate changes in serum leptin levels during GnRH agonist therapy. Twenty regularly menstruating women with uterine leiomyomas were enrolled. These subjects were given GnRH agonist (leuprorelin acetate, 3.75 mg) monthly for 4 months. Serum leptin and estradiol (E2) levels were measured at the two time points of day 1 or 2 of the menstrual cycle and the end of GnRH agonist therapy. Weight, total body fat mass, percentage of body fat, and total body lean mass were measured by whole body scanning with dual-energy X-ray absorptiometry. The ratio of serum leptin levels to total body fat mass (leptin-fat mass ratio), and the ratio of serum leptin levels to total body lean mass (leptin-lean mass ratio) were calculated. All subjects became amenorrheic after the initial administration of GnRH agonist. Baseline E2 levels were 45.4 +/- 21.0 pg/mL, which significantly decreased after GnRH agonist therapy (13.3 +/- 4.2 pg/mL, p<0.01). Baseline leptin levels were 8.7 +/- 8.1 ng/mL, which did not differ from the values after 4 months of GnRH agonist administration (8.9 +/- 6.8 ng/mL). Total body fat mass significantly increased from 20.0 +/- 10.4 to 21.0 +/- 9.4 kg (p<0.05), while total body lean mass significantly decreased (34.5 +/- 4.2 kg to 33.3 +/- 3.9 kg, p<0.01). However, leptin-fat mass ratio after GnRH agonist therapy did not differ from the baseline values (0.39 +/- 0.16 ng/mL/kg vs 0.38 +/- 0.16 ng/mL/kg). Hypogonadism does not have a major impact on circulating leptin levels.

Relative contribution of aging and menopause to changes in lean and fat mass in segmental regions

OBJECTIVE

The aim of the study was to investigate the relative contribution of aging and menopause to the changes in lean and fat mass in segmental regions.

MATERIALS AND METHODS

Subjects were 365 pre- and 201 postmenopausal Japanese women aged between 20 and 70 years old. Age, height, weight, body mass index (BMI, Wt/Ht(2)), age at menopause, years since menopause (YSM), and menopausal status were recorded. Lean and fat mass of the arms, trunk, legs, total body, and the ratio of trunk fat mass to leg fat mass amount (trunk-leg fat ratio) were measured by dual-energy X-ray absorptiometry (DEXA). Regional (arms, lumbar spine, pelvis, legs, and total body) bone mineral density (BMD) were measured by DEXA.

RESULTS

Total body lean mass and regional BMD decreased (P < 0.001), while percentage of body fat, trunk fat mass, and trunk-leg fat ratio increased (P < 0.001) with aging and after menopause. On multiple regression analyses, trunk and total body lean mass were inversely correlated with menopausal status (P < 0.001 and 0.05, respectively) but not with age. Trunk fat mass, trunk-leg fat ratio, and percentage of body fat were positively correlated with age (P < 0.01) but not with menopausal status. Regional BMD were more inversely correlated with menopausal status (P < 0.001) than age.

CONCLUSION

Decrease in lean mass and BMD are more menopause-related, while the shift toward upper body fat distribution and overall adiposity are more age-related. Lean tissue is similar to bone tissue from the viewpoint of more undergoing menopausal effect.

Inverse relationship between the changes in trunk lean and fat mass during gonadotropin-releasing hormone agonist therapy

OBJECTIVE

The aim of the present study was to investigate the relationship between the changes in lean and fat mass during gonadotropin-releasing hormone agonist (GnRH agonist) therapy.

METHODS

Subjects were 24 premenopausal women (mean age, 39.5+/-9.4 years; range, 32-52 years) with uterine leiomyomas. They were given GnRH agonist (leuprorelin acetate, 3.75 mg) monthly for 4 months. Age and height were recorded. Body weight, regional and total body composition, and the ratio of trunk fat mass to leg fat mass (trunk-leg fat ratio) were assessed by whole body scanning with dual-energy X-ray absorptiometry. Changes in these variables were investigated. Relationships between the changes in regional lean and fat mass were investigated using Pearson's correlation test.

RESULTS

Trunk fat mass significantly increased from 8616+/-3538 to 9265+/-3526 g (P<0.01) and trunk-leg fat ratio significantly increased (1.02+/-0.39 to 1.07+/-0.39, P<0.05). Trunk lean mass significantly decreased from 18,509+/-2602 to 17,916+/-2402 g (P<0.01). However, body weight, and lean and fat mass component in the extremities did not change. Change in trunk fat mass was inversely correlated with change in trunk lean mass (r=-0.439, P<0.05), but such relationships were not observed in arm and leg regions.

CONCLUSION

Inverse relationship between the changes in trunk lean and fat mass is observed during GnRH agonist therapy.

Relationship of upper body obesity to menstrual disorders

BACKGROUND

The purpose of the present study was to investigate the relative contribution of upper and lower body obesity to obesity-related menstrual disorders.

METHODS

Women with polycystic ovary syndrome (PCOS) were excluded from the study. Eighty-three obese women with a body mass index (BMI, Wt/Ht2) of more than 25 kg/m2 were classified into two groups according to their menstrual status: one with menstrual disorders (n = 39; mean age +/- standard deviation, 31.6 +/- 4.9 years) and the other group (controls) with regular menstruation (n = 44; 32.2 +/- 4.4 years). Age, age at menarche, height, weight, and BMI were recorded. Trunk fat mass, leg fat mass, the ratio of trunk to leg fat mass amount (trunk-leg fat ratio), body fat mass, and the percentage of body fat were measured by whole-body scanning with dual-energy X-ray absorptiometry. Baseline characteristics and anthropometric variables were compared between the two groups.

RESULTS

Trunk-leg fat ratio in women with menstrual disorders was 1.48 +/- 0.29, which was significantly higher than that in controls (1.25 +/- 0.38, p < 0.01). Trunk fat mass was also significantly higher in women with menstrual disorders than in controls (14.9 +/- 4.1 kg vs. 12.9 +/- 3.8 kg, p < 0.05). However, BMI, percentage of body fat, body fat mass, and leg fat mass did not differ between the two groups. Age, age at menarche, height, and weight did not differ between the two groups.

CONCLUSION

Upper body, but not lower body, obesity is associated with menstrual disorders.

Precocious puberty and body composition: effects of GnRH analog treatment

INTRODUCTION

Body composition changes with age and sex differences become significant only after puberty. Boys and girls before the age of 8 yr do not differ in fat, lean or bone mineral mass. Hormonal influences during pubertal development determine the physiological adult male and female body composition phenotype.

AIM

The aim of our study was to evaluate body composition changes due to central precocious puberty (PP) and the specific effects of therapy on these modifications.

SUBJECTS AND METHODS

Sixteen patients (14 girls, 2 boys) were included in the study. They were diagnosed as affected by idiopathic PP according to standard hormonal and clinical criteria; anatomic alterations of hypothalamus-hypophysis region were excluded by MRI. Mean age at diagnosis was 5.9 +/- 1.9 yr. All patients received GnRH analog (Leuprolide or Triptorelin) treatment subcutaneously every 4 weeks for at least 1 yr. Mean period of treatment was 3.4 +/- 1.9 yr. Standard anthropometry and body composition analysis were performed at baseline and every 6-12 months. A group of healthy subjects with normal timing of puberty was matched (for age or for pubertal stage) served as the control group (CA or CP, respectively).

RESULTS

Patients with PP showed at baseline a significant increase of BMI and relative body weight; lean and fat compartments were also increased but not significantly. During treatment, the PP group showed increased fat mass compared to CA (p<0.05), while no difference was found between PP and CP. Lean mass was similar to CA but lower than in CP (p<0.05). During treatment a significant increase in lean mass (both as total as well as limb mass) was observed. After stopping treatment there was no difference between PP and CP, except for lower lean mass (p<0.04).

CONCLUSION

When puberty occurs precociously, lean and fat mass are not significantly different from age-matched control subjects. Data collected during treatment confirm a shortening of prepubertal lean mass development and the block of further lean mass development due to puberty itself, while fat mass accumulation continues. The net result of these modifications determines a typical body composition pattern in PP patients, after the end of therapy: lean mass is reduced by a shortening of the prepubertal growing period and by the "menopausal effect" of treatment itself. Fat mass is increased as a consequence of therapy and could lead to future obesity.