Short-term response of bone turnover to low-dose oral contraceptives in exercising women with hypothalamic amenorrhea

Bone health in functional hypothalamic amenorrhea: What the endocrinologist needs to know

In the original definition by Klinefelter, Albright and Griswold, the expression "hypothalamic hypoestrogenism" was used to describe functional hypothalamic amenorrhoea (FHA). Given the well-known effects of estrogens on bone, the physiopathology of skeletal fragility in this condition may appear self-explanatory. Actually, a growing body of evidence has clarified that estrogens are only part of the story. FHA occurs in eating disorders, overtraining, and during psychological or physical stress. Despite some specific characteristics which differentiate these conditions, relative energy deficiency is a common trigger that initiates the metabolic and endocrine derangements contributing to bone loss. Conversely, data on the impact of amenorrhoea on bone density or microarchitecture are controversial, and reduced bone mass is observed even in patients with preserved menstrual cycle. Consistently, oral estrogen-progestin combinations have not proven beneficial on bone density of amenorrheic women. Low bone density is a highly prevalent finding in these patients and entails an increased risk of stress or fragility fractures, and failure to achieve peak bone mass and target height in young girls. Pharmacological treatments have been studied, including androgens, insulin-like growth factor-1, bisphosphonates, denosumab, teriparatide, leptin, but none of them is currently approved for use in FHA. A timely screening for bone complications and a multidisciplinary, customized approach aiming to restore energy balance, ensure adequate protein, calcium and vitamin D intake, and reverse the detrimental metabolic-endocrine changes typical of this condition, should be the preferred approach until further studies are available.

Complete Androgen Insensitivity Syndrome: Dilemmas for Further Management after Gonadectomy

Complete androgen insensitivity syndrome is a rare condition, wherein a genetic male is phenotypically female and is raised as a female. Treatement requires timely gonadectomy, need for long term hormonal replaceent therapy, psycological and genetic counseling. The type, dose, duration of hrt is not well studied. Reproductive issues also need to be addressed in these young woman. We report here a case of complete androgen insensitivity which posed a quandary for management of long term bone health. Review of literature for management is discussed. These cases are best managed by a multi-disciplenary team comprising of gynecologist, geneticist, endocrinologist and clinical psycologist or psychiatrist.

Severely restricting energy intake for 24 h does not affect markers of bone metabolism at rest or in response to re-feeding

PURPOSE

Intermittent energy restriction commonly refers to ad libitum energy intake punctuated with 24 h periods of severe energy restriction. This can improve markers of metabolic health but the effects on bone metabolism are unknown. This study assessed how 24 h severe energy restriction and subsequent refeeding affected markers of bone turnover.

METHODS

In a randomised order, 16 lean men and women completed 2, 48 h trials over 3 days. On day 1, participants consumed a 24 h diet providing 100% [EB: 9.27 (1.43) MJ] or 25% [ER: 2.33 (0.34) MJ] of estimated energy requirements. On day 2, participants consumed a standardised breakfast (08:00), followed by an ad libitum lunch (12:00) and dinner (19:30). Participants then fasted overnight, returning on day 3. Plasma concentrations of C-terminal telopeptide of type I collagen (CTX), procollagen type 1 N-terminal propeptide (P1NP) and parathyroid hormone (PTH) were assessed as indices of bone metabolism after an overnight fast on days 1-3, and for 4 h after breakfast on day 2.

RESULTS

There were no differences between trials in fasting concentrations of CTX, P1NP or PTH on days 1-3 (P > 0.512). During both trials, consuming breakfast reduced CTX between 1 and 4 h (P < 0.001) and PTH between 1 and 2 h (P < 0.05), but did not affect P1NP (P = 0.773) Postprandial responses for CTX (P = 0.157), P1NP (P = 0.148) and PTH (P = 0.575) were not different between trials. Ad libitum energy intake on day 2 was greater on ER [12.62 (2.46) MJ] than EB [11.91 (2.49) MJ].

CONCLUSIONS

Twenty-four hour severe energy restriction does not affect markers of bone metabolism.

Rationale and study design of an intervention of increased energy intake in women with exercise-associated menstrual disturbances to improve menstrual function and bone health: The REFUEL study

Purpose

Exercising women who consume inadequate energy relative to expenditure are at risk for downstream health consequences, such as menstrual cycle disturbances and poor bone health. Collectively, these conditions are known as the Female Athlete Triad (Triad). Clinicians often prescribe hormonal contraceptives to address this issue; however, the recommended treatment is reversal of the energy deficit. This paper describes the design of the REFUEL study, a randomized controlled trial (RCT) that explored the effectiveness of a 12-month intervention of increased energy intake on the reversal of an unhealthy energetic status and menstrual dysfunction and subsequent improvements in bone health in exercising women with severe menstrual cycle disturbances.

Methods

Women between the ages of 18–35 years and participating in at least 2 h/week of purposeful exercise were recruited. Those who reported irregular or absent menstrual cycles and were determined to have an exercise-associated menstrual disturbance (EAMD) were randomized into either the treatment group (EAMD + Cal), which was instructed to increase caloric intake throughout the intervention, or a control group (EAMD Control). Women who reported eumenorrhea were eligible for the ovulatory (OV) Control group. Repeated measures of energetic and metabolic status, reproductive status, and skeletal health were obtained.

Discussion

The REFUEL study is the first RCT to explore a non-pharmacological treatment approach among exercising women with the Triad. 118 women were randomized, and 55 women completed the entire study. The findings of this study have the potential to inform and alter clinical practice for exercising young women who present with this condition.

Effect of combined oral contraceptives on orthodontic tooth movement in a female rat model

Background

To investigate the effect of combined oral contraceptives (COC) on orthodontic tooth movement (OTM) and periodontal remodelling in a female rat model.

Methods

A total of 80 three-month-old female, Sprague-Dawley rats were randomly divided into experimental and control groups. The maxillary first molars were moved mesially using nickel-titanium coil springs (50 g force). The experimental group (N = 40) ingested 1.5 ml COC (Marvelon, 0.12 mg/d, N.V. Organon, Oss, The Netherlands) daily. The control group (N = 40) ingested 1.5 ml saline (0.9% sodium chloride) daily. After 7, 14, 21 and 28 days of force application, 10 rats in each group were euthanased and a vernier calliper was used to measure the orthodontic movement of the first molar. Root resorption at pressure areas was assessed by H and E staining. Micro-CT was used to detect alveolar bone mineral density.

Results and conclusion

The amount of OTM in the experimental group (0.46 ± 0.16 mm) was significantly less than in the control group (0.85 ± 0.25 mm; p = 0.003) during the 28 days of observation. There were significantly smaller (p = 0.002) root resorption lacunae in the experimental group (111710 ± 4037 pixels) compared with the control group (204962 ± 21318 pixels) after 28 days. There was no statistically significant difference in the bone mineral density between the experimental and control groups throughout the study period (p > 0.05 at each time point). The short-term administration of COC may retard tooth movement and reduce the level of root resorption during OTM in female rats.

A summary of the influence of exogenous estrogen administration across the lifespan on the GH/IGF-1 axis and implications for bone health

Bone growth, development, and remodeling are modulated by numerous circulating hormones. Throughout the lifespan, the extent to which each of the hormones impacts bone differs. Understanding the independent and combined impact of these hormones on controlling bone remodeling allows for the development of more informed decision making regarding pharmacology, specifically the use of hormonal medication, at all ages. Endocrine control of bone health in women is largely dictated by the growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis and the hypothalamic-pituitary-ovarian (HPO) axis. Growth hormone, secreted from the pituitary gland, stimulates cells in almost every tissue to secrete IGF-1, although the majority of circulating IGF-1 is produced hepatically. Indeed, systemic IGF-1 concentrations have been found to be correlated with bone mineral density (BMD) in both pre- and post-menopausal women and is often used as a marker of bone formation. Sex steroids produced by the ovaries, namely estradiol, mediate bone resorption through binding to estrogen receptors on osteoclasts and osteoblasts. Specifically, by increasing osteoclast apoptosis and decreasing osteoblast apoptosis, adequate estrogen levels prevent excessive bone resorption, which helps to explain the rapid decline in bone mass that occurs with the menopausal decrease in estrogen production. Though there are documented correlations between endogenous estrogen concentrations and GH/IGF-1 dynamics, this relationship changes across the lifespan as sex-steroid dynamics fluctuate and, possibly, as tissue responsiveness to GH stimulation decreases. Aside from the known role of endogenous sex steroids on bone health, the impact of exogenous estrogen administration is of interest, as exogenous formulations further modulate GH and IGF-1 production. However, the effect and extent of GH and IGF-1 modulation seems to be largely dependent on age at administration and route of administration. Specifically, premenopausal women using combined oral contraceptive therapy (COC), post-menopausal women taking oral hormone therapy (HT), and both pre- and post-menopausal women using a transdermal form of estrogen therapy (COC or HT) demonstrate disparate GH/IGF-1 responses to exogenous estrogen. This review serves to summarize what is currently known regarding the influence of exogenous estrogen administration across the lifespan on the GH/IGF-1 axis and implications for bone health.

Endocrine disorders in adolescent and young female athletes: impact on growth, menstrual cycles, and bone mass acquisition

CONTEXT

Puberty is a crucial period of dramatic hormonal changes, accelerated growth, attainment of reproductive capacity, and acquisition of peak bone mass. Participation in recreational physical activity is widely acknowledged to provide significant health benefits in this period. Conversely, intense training imposes several constraints, such as training stress and maintenance of very low body fat to maximize performance. Adolescent female athletes are therefore at risk of overtraining and/or poor dietary intake, which may have several consequences for endocrine function. The "adaptive" changes in the hypothalamic-pituitary-gonadal, -adrenal, and somatotropic axes and the secretory role of the adipose tissue are reviewed, as are their effects on growth, menstrual cycles, and bone mass acquisition.

DESIGN

A systematic search on Medline between 1990 and 2013 was conducted using the following terms: "intense training," "physical activity," or "exercise" combined with "hormone," "endocrine," and "girls," "women," or "elite female athletes." All articles reporting on the endocrine changes related to intense training and their potential implications for growth, menstrual cycles, and bone mass acquisition were considered.

RESULTS AND CONCLUSION

Young female athletes present a high prevalence of menstrual disorders, including delayed menarche, oligomenorrhea, and amenorrhea, characterized by a high degree of variability according to the type of sport. Exercise-related reproductive dysfunction may have consequences for growth velocity and peak bone mass acquisition. Recent findings highlight the endocrine role of adipose tissue and energy balance in the regulation of homeostasis and reproductive function. A better understanding of the mechanisms whereby intense training affects the endocrine system may orient research to develop innovative strategies (ie, based on nutritional or pharmacological approaches and individualized modalities of training and competition) to improve the medical care of these adolescents and protect their reproductive function.

Biochemical markers of bone turnover - uses and limitations

Bone turnover markers of resorption and formation are released during the process of bone remodelling. These markers have been extensively studied in a number of therapeutic trials of osteoporosis during the past decade. This has led to better understanding of their physiology, clinical applications and possible ways to optimize analytical techniques. Bone markers can complement the results of bone mineral density in the management of osteoporosis, but their use in clinical practice is challenged by pre-analytical and analytical variability. This review will discuss different types of bone markers, their limitations, use in different metabolic bone diseases and current recommendations from the International Osteoporosis Foundation and the International Federation of Clinical Chemistry and Laboratory Medicine bone marker standards working group.

Androgen insensitivity syndrome

Androgen insensitivity syndrome (AIS) is a disorder caused by a mutation of the gene encoding the androgen receptor (AR; Xq11-q12). The prevalence of AIS has been estimated to be one case in every 20,000 to 64,000 newborn males for the complete syndrome (CAIS), and the prevalence is unknown for the partial syndrome (PAIS). The symptoms range from phenotypically normal males with impaired spermatogenesis to phenotypically normal women with primary amenorrhea. Various forms of ambiguous genitalia have been observed at birth. The diagnosis is confirmed by determining the exact mutation in the AR gene. PAIS individuals require precise diagnosis as early as possible so that the sex can be assigned, treatment can be recommended, and they can receive proper genetic counseling. After birth, differential diagnosis should be performed using other forms of abnormal sexual differentiation of primary amenorrhea. The treatment of AIS is based on reinforcement sexual identity, gonadectomy planning, and hormone replacement therapy. The prognosis for CAIS is good if the testicular tissue is removed at the appropriate time. For PAIS, the prognosis depends on the ambiguity of the genitalia and physical and psychosocial adjustment to the assigned sex.

The effect of oral contraceptives on orthodontic tooth movement in rat

INTRODUCTION

The purpose of this study was to investigate the effect of ethinyl estradiol/norgestrel - used in some oral contraceptives- on orthodontic tooth movement in Wistar rats.

MATERIAL AND METHODS

Forty eight female three-month old Wistar rats with an average weight of 250 ± 25 gr were divided into two experimental and control groups. One week prior to appliance insertion and during the appliance therapy period, 100 mcg/kg/day of ethinyl estradiol and 1 mg/kg/days of norgestrel were administered to the experimental group by gavage; meanwhile the control group received an equivalent volume of Sodium Chloride 0.9 % (Saline). Maxillary central incisors were tipped distally by insertion of springs exerting 30 g force. Two, seven and fourteen days after spring insertion animals were sacrificed. The mesioincisal distance between maxillary incisors were measured. Subsequently, histological sections were prepared for histomorphometric studies.

RESULTS

14 days after force application the orthodontic tooth movement was significantly lower in the experimental group (p<0.05). The number of osteoclasts were significantly lower in the experimental group 2, 7 and 14 days after spring insertion (p<0.05).

CONCLUSION

Ethinyl estradiol/norgestrel (oral contraceptives) can significantly decrease the amount of tooth movement in the linear phase.

Adiponectin and bone metabolism markers in female rowers: eumenorrheic and oral contraceptive users

This study investigated whether adiponectin, bone formation (osteocalcin) and bone resorption [type I carboxyterminal telopeptide (ICTP)] values are influenced by menstrual cycle phase and oral contraceptive use in female rowers. Twenty-four rowers divided into normally cycling athletes (NOC; no.=15) and athletes taking oral contraceptive pills (OC; no.=9) participated in this study. Fasting blood samples, body composition and aerobic capacity measurements were taken during the follicular (FP) and the luteal (LP) phases of the menstrual cycle. Adiponectin, insulin, glucose, insulin resistance, body composition and aerobic capacity did not fluctuate significantly during menstrual cycle in both groups. Osteocalcin and ICTP were lower (p<0.05) in OC compared with NOC, but did not change significantly across menstrual cycle phases in both groups. Estradiol and progesterone were not related to adiponectin, osteocalcin or ICTP (r<0.147; p>0.05). Adiponectin was correlated (p<0.05) with osteocalcin (r=0.452) and fat free mass (r=0.428), and osteocalcin was related (p<0.05) to insulin (r=-0.413), glucose (r=-0.486) and insulin resistance (r=-0.528). In conclusion, adiponectin was not affected by menstrual cycle phase and OC use in female rowers, while bone metabolism markers were lower in OC compared to NOC groups. Adiponectin and osteocalcin were interrelated and may characterise energy homeostasis in female athletes.

The effects of hormonal contraceptives on bone turnover markers and bone health

Sex hormones are important regulators of bone metabolism. As hormonal contraceptives contain either oestrogens or progestins, or a combination thereof, it is conceivable that these widely used agents have an effect on bone metabolism and bone health. The main users of hormonal contraceptives, adolescent girls and young women, are still building bone and accruing bone mass and may therefore be particularly susceptible to the effects of hormonal contraceptives on bone. Despite these concerns, the effects of hormonal contraceptives on bone health are still poorly understood. As biochemical markers of bone turnover have been proven useful tools in the assessment and monitoring of bone metabolism, we reviewed the effects of combined and gestagen-only hormonal contraceptives on bone turnover markers and related effects on bone mineral density and fracture risk in premenopausal women, as documented in the literature until January 2009.