The effects of bone therapy on tibial bone loss in young women with anorexia nervosa

Bone Perspectives in Functional Hypothalamic Amenorrhoea: An Update and Future Avenues

One of the most important and potentially long-lasting detrimental consequences of Functional Hypothalamic Amenorrhoea (FHA) is on skeletal homeostasis. Beyond oestrogen deficiency, FHA is associated with a cascade of additional neuro-endocrine and metabolic alterations, some adaptive, but which combine to disrupt skeletal homeostasis. Ultimately, this leads to a two-fold increased risk of fractures in women with FHA compared to healthy eumenorrhoeic women. Although the cornerstone of management of FHA-related bone loss remains recovery of menses via restoration of metabolic/psychological balance, there is rapidly developing evidence for hormonal manipulations (with a particular emphasis on route of administration) and other pharmacological treatments that can protect or improve skeletal homeostasis in FHA. In this mini-review, we provide an update on the pathophysiology, clinical management and future avenues in the field from a bone perspective.

Eating disorders and bone metabolism in women

PURPOSE OF REVIEW

Eating Disorders are psychiatric disorders associated with a high risk for low bone mineral density (BMD) and fractures. Low BMD is a consequence of undernutrition, changes in body composition, and hormonal alterations. This review summarizes recent findings regarding novel strategies for assessing bone outcomes in patients with eating disorders, factors contributing to altered bone metabolism, and possible therapeutic strategies.

RECENT FINDINGS

Emerging research in this field suggests that not only anorexia nervosa, but also bulimia nervosa results in lower BMD compared to controls. To date studies of bone structure, and all randomized controlled trials examining the impact of various therapies on bone outcomes in anorexia nervosa, have focused on adolescent girls and women. We discuss the impact of anorexia nervosa on bone structure, and associations of resting energy expenditure, marrow adipose tissue (including the ratio of saturated to unsaturated fat), and cold activated brown adipose tissue with BMD and bone structure. Promising strategies for treatment include physiological estrogen replacement (rather than oral contraceptives) in adolescent girls with anorexia nervosa, and bisphosphonates, as well as teriparatide, in adult women with anorexia nervosa.

SUMMARY

Recent data on (i) BMD and bone structure in adolescent girls and women with eating disorders, (ii) factors that contribute to altered bone metabolism, and (iii) randomized controlled trials reporting positive effects of physiologic estrogen replacement, bisphosphonates and teriparatide on bone health, provide us with a greater understanding of the impact of eating disorders on bone and novel management strategies.

Pharmacological treatment options for low Bone Mineral Density and secondary osteoporosis in Anorexia Nervosa: A systematic review of the literature

OBJECTIVE

Although there are several evidence-based treatments available to increase Bone Mineral Density (BMD) and reduce fracture risk in aging men and women, there are still uncertainties regarding which treatments are efficacious in reducing lifetime fracture risk in women with Anorexia Nervosa (AN).

METHODS

Medline, PsychInfo, Embase and the Cochrane Database were searched for English Language Studies. Inclusion criteria were studies of females of any age with AN who received pharmacological treatment with the primary aim to increase BMD or reduce fracture risk. Data were extracted from each study regarding pharmacological treatment and dosage used, BMD and bone formation marker outcomes; and participant characteristics including age, Body Mass Index (BMI), duration of AN, and duration of amenorrhea.

RESULTS

675 studies were reviewed, of which 19 fit the inclusion criteria and were included in the final review, investigating a total of 1119 participants; 10 of the 19 included studies were double-blind RCTs. The remaining studies consisted of prospective observational studies, a retrospective cohort study, a case-control study and five non-randomised control trials. Bisphosphonates were effective in increasing BMD in adult women with AN, while estrogen administered transdermally resulted in significant increases in BMD in mature adolescents with AN. Administration of oral contraceptives (OC) did not significantly increase BMD in randomised or controlled trials, however, lifetime OC use was associated with higher spinal BMD.

CONCLUSION

Future research should clarify the safety of long-term bisphosphonate use in adult women with AN, and verify that transdermal estrogen replacement increases BMD in women with AN.

Functional Hypothalamic Amenorrhea: An Endocrine Society Clinical Practice Guideline

COSPONSORING ASSOCIATIONS

The American Society for Reproductive Medicine, the European Society of Endocrinology, and the Pediatric Endocrine Society. This guideline was funded by the Endocrine Society.

OBJECTIVE

To formulate clinical practice guidelines for the diagnosis and treatment of functional hypothalamic amenorrhea (FHA).

PARTICIPANTS

The participants include an Endocrine Society-appointed task force of eight experts, a methodologist, and a medical writer.

EVIDENCE

This evidence-based guideline was developed using the Grading of Recommendations, Assessment, Development, and Evaluation approach to describe the strength of recommendations and the quality of evidence. The task force commissioned two systematic reviews and used the best available evidence from other published systematic reviews and individual studies.

CONSENSUS PROCESS

One group meeting, several conference calls, and e-mail communications enabled consensus. Endocrine Society committees and members and cosponsoring organizations reviewed and commented on preliminary drafts of this guideline.

CONCLUSIONS

FHA is a form of chronic anovulation, not due to identifiable organic causes, but often associated with stress, weight loss, excessive exercise, or a combination thereof. Investigations should include assessment of systemic and endocrinologic etiologies, as FHA is a diagnosis of exclusion. A multidisciplinary treatment approach is necessary, including medical, dietary, and mental health support. Medical complications include, among others, bone loss and infertility, and appropriate therapies are under debate and investigation.

Treatments to Prevent Bone Loss in Functional Hypothalamic Amenorrhea: A Systematic Review and Meta-Analysis

Objective:

We conducted a systematic review and meta-analysis of studies that evaluated the effect of hormonal therapy [estrogen therapy including oral contraceptive pills (OCP)] and bisphosphonates in preventing bone loss in patients with functional hypothalamic amenorrhea (FHA).

Methods:

We searched several electronic databases for controlled and noncontrolled studies that enrolled females of any age presenting with FHA (including athletic, weight loss, and stress-associated amenorrhea/oligomenorrhea) through 9 January 2017. The outcomes of interest were fractures and bone mineral density (BMD). Random effects meta-analysis was used to pool outcomes across studies expressed as weighted mean difference and 95% confidence interval (CI).

Results:

Nine studies reporting on 280 patients that received different hormonal therapies were included. We did not identify studies that evaluated bisphosphonates. Meta-analysis demonstrated a statistically significant increase in BMD of the lumbar spine in patients receiving hormonal therapy after a median follow-up of 12 months (weighted mean difference, 0.032 g/cm²; 95% CI, 0.017 to 0.047; percentage change in BMD, 3.30%; 95% CI, 1.74 to 4.86). There was no substantial effect of receiving hormonal therapy on BMD of the femoral neck, trochanteric region, Ward triangle, or total body BMD. The quality of evidence was low because of the high risk of bias, imprecision (small sample size), and indirectness (as BMD is a surrogate outcome). None of the studies reported the incidence of fractures.

Conclusion:

The current evidence does not support using hormonal therapy for the sole purpose of improving bone health in patients with FHA. There are no data about bisphosphonates in this population.

Anorexia nervosa

Anorexia nervosa (AN) is a psychiatric condition characterized by severe weight loss and secondary problems associated with malnutrition. AN predominantly develops in adolescence in the peripubertal period. Without early effective treatment, the course is protracted with physical, psychological and social morbidity and high mortality. Despite these effects, patients are noted to value the beliefs and behaviours that contribute to their illness rather than regarding them as problematic, which interferes with screening, prevention and early intervention. Involving the family to support interventions early in the course of the illness can produce sustained changes; however, those with a severe and/or protracted illness might require inpatient nursing support and/or outpatient psychotherapy. Prevention programmes aim to moderate the overvaluation of 'thinness' and body dissatisfaction as one of the proximal risk factors. The low prevalence of AN limits the ability to identify risk factors and to study the timing and sex distribution of the condition. However, genetic profiles, premorbid features, and brain structures and functions of patients with AN show similarities with other psychiatric disorders and contrast with obesity and metabolic disorders. Such studies are informing approaches to address the neuroadaptation to starvation and the other various physical and psychosocial deficits associated with AN. This Primer describes the epidemiology, diagnosis, screening and prevention, aetiology, treatment and quality of life of patients with AN.

Bone disease in anorexia nervosa

Anorexia nervosa is a serious psychiatric disorder accompanied by high morbidity and mortality. It is characterized by emaciation due to self-starvation and displays a unique hormonal profile. Alterations in gonadal axis, growth hormone resistance with low insulin-like growth factor I levels, hypercortisolemia and low triiodothyronine levels are almost universally present and constitute an adaptive response to malnutrition. Bone metabolism is likewise affected resulting in low bone mineral density, reduced bone accrual and increased fracture risk. Skeletal deficits often persist even after recovery from the disease with serious implications for future skeletal health. The pathogenetic mechanisms underlying bone disease are quite complicated and treatment is a particularly challenging task.

Teriparatide treatment of osteoporosis in a patient with anorexia nervosa

Osteoporosis commonly occurs in patients with anorexia nervosa (AN) and is often irreversible even after weight restoration. We describe a 52-year-old woman with AN and severe osteoporosis, discovered after she sustained multiple fractures from a fall. She had low weight for most of her life, but was only formally diagnosed with AN 6 years prior to her presentation. She received therapy for her eating disorder and was able to restore weight, which led to a 4.1 % improvement in her bone density. We then treated her with teriparatide for 2 years, which lead to a further 21 % increase in bone density and she has had no recurrence of fractures. Since AN-associated osteoporosis is characterized by low bone formation, teriparatide may be a useful treatment option.

Minireview: The link between fat and bone: does mass beget mass?

Osteoporosis is less common in individuals with high fat mass. This putative osteoprotection is likely an adaptive mechanism that allows obese individuals to better carry their increased body mass. Recent studies have focused on hormones that link fat to bone. Adipokines, such as leptin, modulate bone cells through both direct and indirect actions, whereas molecules activating peroxisome proliferator-activated receptor γ drive mesenchymal stem cell differentiation towards adipocytes away from the osteoblastic lineage. There is emerging evidence that bone-derived osteocalcin regulates insulin release and insulin sensitivity and, hence, might indirectly affect fat mass. Despite these molecular connections between fat and bone, animal and human studies call into question a primary role for body fat in determining bone mass. Mice devoid of fat do not have a skeletal phenotype, and in humans, the observed correlations between bone and body mass are not just due to adipose tissue. An improved understanding of the integrative physiology at the fat-bone interface should allow us develop therapies for both osteoporosis and obesity.

Bone loss in anorexia nervosa: leptin, serotonin, and the sympathetic nervous system

Anorexia nervosa (AN), a disorder characterized by the refusal to sustain a healthy weight, has the highest mortality of any psychiatric disorder. This review presents a model of AN that ties together advances in our understanding of how leptin, serotonin, and hypogonadism are brought about in AN and how they influence bone mass. Serotonin (5-hydroxytryptamine) is a key regulator of satiety and mood. The primary disturbance in AN results from alterations in serotonin signaling. AN patients suffer from serotonergic hyperactivity of Htr1a-dependent pathways that causes dysphoric mood and promotes restrictive behavior. By limiting carbohydrate ingestion, anorexics decrease their serotonin levels. Reduced serotonergic signaling in turn suppresses appetite through Htr1a/2b, decreases dysphoric mood through Htr1a/2a, and activates the sympathetic nervous system (SNS) through Htr2c receptors in the ventromedial hypothalamus. Activation of the SNS decreases bone mass through β2-adrenergic signaling in osteoblasts. Additional topics reviewed here include osteoblastic feedback of metabolism in anorexia, mechanisms whereby dietary changes exacerbate bone loss, the role of caloric restriction and Sirt1 in bone metabolism, hypothalamic hypogonadism's effects on bone mass, and potential treatments.

Treatment of osteopenia and osteoporosis in anorexia nervosa: a systematic review of the literature

OBJECTIVE

To systematically review the evidence supporting treatment of osteopenia and osteoporosis in patients with anorexia nervosa (AN).

DATA SOURCES

We identified controlled clinical studies of interventions for low bone mass in AN via searches of MEDLINE; the Cochrane Library; EMBASE; PsycINFO; and cumulative index to nursing and allied health literature. Outcomes of interest were changes in bone mineral density and fracture incidence.

RESULTS

Six randomized controlled trials (RCTs) and two cohort trials examined five classes of medical therapy on bone mineral density outcomes. One RCT of bisphosphonates showed no benefit and a second flawed RCT showed some benefit; one RCT showed a benefit of insulin-like growth factor-I; none of the five trials evaluating estrogen therapy showed benefit.

DISCUSSION

Although patients with AN are often losing bone mass when they should be optimizing bone growth, there is no good evidence to guide medicinal interventions. Therefore, early detection and weight restoration are of utmost importance whereas ongoing trials define effective therapies.

Strategies to reverse bone loss in women with functional hypothalamic amenorrhea: a systematic review of the literature

Functional hypothalamic amenorrhea (FHA) impairs the attainment of peak bone mass and as such can increase the risk of fractures later in life. To document available treatment strategies, we conducted a systematic review of the literature. We report that hormonal therapies have limited effectiveness in increasing bone mass, whereas increased caloric intake resulting in weight gain and/or resumption of menses is an essential strategy for restoring bone mass in women with FHA.

INTRODUCTION

Women with functional hypothalamic amenorrhea (FHA) may not achieve peak bone mass (PBM), which increases the risk of stress fractures, and may increase the risk of osteoporotic fractures in later life.

METHODS

To identify effective treatment strategies for women with FHA, we conducted a systematic review of the literature. We included randomized controlled trials (RCTs), cross-sectional studies, and case studies that reported on the effects of pharmacological and non-pharmacological interventions on bone mineral density (BMD) or bone turnover in women with FHA.

RESULTS

Most published studies (n=26) were designed to treat the hormonal abnormalities observed in women with FHA (such as low estrogen, leptin, insulin-like growth factor-1, and DHEA); however none of these treatments demonstrated consistent improvements in BMD. Therapies containing an estrogen given for 8-24 months resulted in variable improvements (1.0-19.0%) in BMD, but failed to restore bone mass to that of age-matched controls. Three studies reported on the use of bisphosphonates (3-12 months) in anorexic women, which appear to have limited effectiveness to improve BMD compared to nutritional treatments. Another three investigations showed no improvements in BMD after androgen therapy (DHEA and testosterone) in anorexic women. In contrast, reports (n=9) describing an increase in caloric intake that results in weight gain and/or the resumption of menses reported a 1.1-16.9% increase in BMD concomitant with an improvement in bone formation and reduction in bone resorption markers.

CONCLUSIONS

Our literature review indicates that the most successful, and indeed essential strategy for improving BMD in women with FHA is to increase caloric intake such that body mass is increased and there is a resumption of menses. Further long-term studies to determine the persistence of this effect and to determine the effects of this and other strategies on fracture risk are needed.

Female high-school varsity athletics: an opportunity to improve bone mineral density

The present study investigated whether moderate, organized physical activity during high school has a positive residual effect on bone mineral density (BMD) in 30-35-year-old females. Seventy-three female former high-school varsity athletes and 67 self-reported low-activity age-matched controls completed a collegiate women's health survey and participated in a one-time clinical visit with bone scan. Lumbar (L1-L4) spine BMD, total hip BMD, percentage body fat, age at menarche, history of amenorrhea, family history of osteoporosis, college alcohol consumption, number of high school varsity seasons, as well as current nutritional intake (including calcium), number of weekly weight training sessions, and caloric expenditure were assessed. Using a saturated linear regression model, current percentage body fat and number of high school seasons predicted 22% of the observed variation in total hip BMD and 25% of the observed variation of lumbar (L1-L4) spine BMD (P<0.001). High school athletes were more likely to be frequent adult exercisers (P<0.001). Athletic participants were more likely to have denser hip and spine bones than low-activity controls. Results suggest that participation in high school athletics is associated with greater BMD. Additionally, the varsity athletes continued to exercise frequently in their early 30s.

Open Issues in Anorexia Nervosa: Prevention and Therapy of Bone Loss

Anorexia nervosa and diet-induced amenorrhea have an important impact not only on gynecological health but also on bone mass, especially if the disease is not promptly recognized and treated. This is particularly important because these conditions usually arise in adolescence, when peak bone mass is normally achieved. In this article we discuss the therapeutic issues related to bone loss associated with eating disorders.