A 2-year prospective study of bone metabolism and bone mineral density in adolescents with anorexia nervosa

Deficiency of glucocorticoid receptor in bone marrow adipocytes has mild effects on bone and hematopoiesis but does not influence expansion of marrow adiposity with caloric restriction

Introduction

Unlike white adipose tissue depots, bone marrow adipose tissue (BMAT) expands during caloric restriction (CR). Although mechanisms for BMAT expansion remain unclear, prior research suggested an intermediary role for increased circulating glucocorticoids.

Methods

In this study, we utilized a recently described mouse model (BMAd-Cre) to exclusively target bone marrow adipocytes (BMAds) for elimination of the glucocorticoid receptor (GR) (i.e. Nr3c1) whilst maintaining GR expression in other adipose depots.

Results

Mice lacking GR in BMAds (BMAd-Nr3c1 -/-) and control mice (BMAd-Nr3c1 +/+) were fed ad libitum or placed on a 30% CR diet for six weeks. On a normal chow diet, tibiae of female BMAd-Nr3c1-/- mice had slightly elevated proximal trabecular metaphyseal bone volume fraction and thickness. Both control and BMAd-Nr3c1-/- mice had increased circulating glucocorticoids and elevated numbers of BMAds in the proximal tibia following CR. However, no significant differences in trabecular and cortical bone were observed, and quantification with osmium tetroxide and μCT revealed no difference in BMAT accumulation between control or BMAd-Nr3c1 -/- mice. Differences in BMAd size were not observed between BMAd-Nr3c1-/- and control mice. Interestingly, BMAd-Nr3c1-/- mice had decreased circulating white blood cell counts 4 h into the light cycle.

Discussion

In conclusion, our data suggest that eliminating GR from BMAd has minor effects on bone and hematopoiesis, and does not impair BMAT accumulation during CR.

Transition of young adults with metabolic bone diseases to adult care

As more accurate diagnostic tools and targeted therapies become increasingly available for pediatric metabolic bone diseases, affected children have a better prognosis and significantly longer lifespan. With this potential for fulfilling lives as adults comes the need for dedicated transition and intentional care of these patients as adults. Much work has gone into improving the transitions of medically fragile children into adulthood, encompassing endocrinologic conditions like type 1 diabetes mellitus and congenital adrenal hyperplasia. However, there are gaps in the literature regarding similar guidance concerning metabolic bone conditions. This article intends to provide a brief review of research and guidelines for transitions of care more generally, followed by a more detailed treatment of bone disorders specifically. Considerations for such transitions include final adult height, fertility, fetal risk, heritability, and access to appropriately identified specialists. A nutrient-dense diet, optimal mobility, and adequate vitamin D stores are protective factors for these conditions. Primary bone disorders include hypophosphatasia, X-linked hypophosphatemic rickets, and osteogenesis imperfecta. Metabolic bone disease can also develop secondarily as a sequela of such diverse exposures as hypogonadism, a history of eating disorder, and cancer treatment. This article synthesizes research by experts of these specific disorders to describe what is known in this field of transition medicine for metabolic bone diseases as well as unanswered questions. The long-term objective is to develop and implement strategies for successful transitions for all patients affected by these various conditions.

Changes in trabecular bone score and bone density in female adolescents with anorexia nervosa: a longitudinal study

Impaired bone health is a common complication of anorexia nervosa (AN). We aimed to assess longitudinal changes in bone mineral density (BMD) and trabecular bone score (TBS), a measure of bone quality, in female adolescents with anorexia nervosa (AN). We conducted a retrospective longitudinal study of 41 female adolescents with AN who underwent two dual-energy X-ray absorptiometry (DXA) scans. Clinical data, including age, weight, height, body mass index (BMI), and DXA measurements were retrieved from the medical charts. Lumbar bone mineral apparent density (BMAD) was calculated to correct for size. Changes (Δ) in BMD, BMAD, and TBS were examined for correlations with clinical characteristics. Mean ages at the time of DXA scans were 14.8±1.9 and 16.8±2.0 years. There was a significant improvement in anthropometric parameters and DXA measurements at the second DXA scan. However, these values were still significantly lower than expected in the general population. The Δlumbar BMD Z-score was 0.3±0.7, the Δlumbar BMAD Z-score was 0.2±0.7 and the ΔTBS Z-score was 0.5±0.7. ΔTBS Z-score was positively correlated with Δheight Z-score, Δweight Z-score and ΔBMI Z-scores, and negatively correlated height Z-score, weight Z-score and TBS Z-scores at the first DXA scan (p<0.05). Δheight Z-score, ΔBMI Z-score and the progression from early to late puberty were identified as significant independent predictors of Δlumbar BMAD Z-score (p<0.05). During two years of treatment, both BMD and TBS increased significantly. Improvement in height and in weight status, and progression in puberty are predictors of improvement in BMD and TBS.

Anorexia Nervosa and Osteoporosis

Patients with anorexia nervosa (AN) often experience low bone mineral density (BMD) and increased fracture risk, with low body weight and decreased gonadal function being the strongest predictors of the observed bone mineral deficit and fractures. Other metabolic disturbances have also been linked to bone loss in this group of patients, including growth hormone resistance, low insulin-like growth factor-1 (IGF-1) concentrations, low leptin concentrations, and hypercortisolemia. However, these correlations lack definitive evidence of causality. Weight restoration and resumption of menstrual function have the strongest impact on increasing BMD. Other potential treatment options include bisphosphonates and teriparatide, supported by data from small clinical trials, but these agents are not approved for the treatment of low BMD in adolescents or premenopausal women with AN.

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.

Bone mineral density at extremely low weight in patients with anorexia nervosa

OBJECTIVE

Low bone mineral density (BMD) is a frequent and invalidating consequence of chronic undernourishment in patients with anorexia nervosa (AN). The aim of this study was to assess prevalence and clinic-biological correlates of low BMD and fractures in extremely undernourished inpatients with AN.

DESIGN

Retrospective cohort study.

PATIENTS AND MEASUREMENTS

This study included 97 extremely malnourished female inpatients with AN consecutively admitted over 2 years. Clinical-biological variables, history of fractures and BMD by dual-energy X-ray absorptiometry (DXA) were examined to find predictors of low BMD and fractures.

RESULTS

The prevalence of low BMD was of 51% for lumbar spine and 38% for femoral neck. Z-scores were lower at lumbar spine (-2.2 ± 1.2 SD) than at femoral neck (-1.9 ± 0.9 SD) (P<.01). Fragility fractures were reported by 10% of patients. BMD was mainly predicted by FFM, illness duration, age at onset and restricting AN (P<.05). Fractures were predicted by sodium concentrations, femoral neck Z-score and illness duration (P<.03).

CONCLUSION

Extremely severe patients with AN have high prevalence of low BMD, predicted by severity and chronicity of malnutrition.

Body Composition in Adolescents and Young Adults with Anorexia Nervosa: A Clinical Review

BACKGROUND

Anorexia nervosa is a serious health condition characterized by a significant low body weight and alteration in body composition components.

AIM

In the current paper, we aim to summarize the available literature concerning changes in body fat, lean, and bone masses, during anorexia nervosa and after complete weight restoration.

METHODS

Data were summarized using a narrative approach based on clinical expertise in the interpretation of the available evidence base in the literature.

RESULTS

The available data revealed three main findings. Firstly, anorexia nervosa causes a significant reduction in body fat mass, however it is completely restored after short-term weight normalization but with a central adiposity phenotype that does not seem to negatively influence treatment outcomes and appears to normalize after 1 year of normal weight maintenance. Secondly, anorexia nervosa causes a significant reduction in bone mineral density, but weight restoration is associated first (≈12 months) with stabilization of bone mineral density, followed by improvements (after ≈16 months); and finally, with complete normalization (after ≈30 months) after normal-weight maintenance. Thirdly, during anorexia nervosa loss of lean and skeletal body mass occurring in particular from the extremities rather than the central regions has been consistently reported, especially in patients with a Body Mass Index (BMI) ≤ 16.5 Kg/m2 however short-term weight restoration is associated with complete normalization.

CONCLUSION

Anorexia nervosa adversely affects body composition, however this medical complication seems to be reversible through the main treatment strategy of body weight restoration followed by normal weight maintenance, and this should be openly discussed with patients.

Anorexia Nervosa and Osteoporosis: Pathophysiology and Treatment

Anorexia nervosa (AN) affects 2.9 million people, many of whom experience bone loss and increased fracture risk. In this article, we review data on the underlying pathophysiology of AN-related osteoporosis and possible approaches to disease management. Available research suggests that low body weight and decreased gonadal function are the strongest predictors of bone loss and fractures in patients with AN. Additionally, other metabolic disturbances have been linked to bone loss, including growth hormone resistance, low leptin concentrations, and hypercortisolemia, but those correlations are less consistent and lack evidence of causality. In terms of treatment of AN-related bone disease, weight gain has the most robust impact on bone mineral density (BMD). Restoration of gonadal function seems to augment this effect and may independently improve BMD. Bisphosphonates, insulin-like growth factor 1 supplementation, and teriparatide may also be reasonable considerations, however need long-term efficacy and safety data.

Longitudinal changes in bone parameters in young girls with anorexia nervosa

BACKGROUND

Anorexia nervosa (AN) during childhood and adolescence has been reported to adversely affect bone health, but few studies have investigated longitudinal changes.

METHOD

DXA-derived bone parameters and body composition were retrospectively assessed in 111 young girls with AN with a median age of 15.4 years (10.9, 19.8). In 68 (61%) vertebral fracture assessment (VFA) was performed and in 31 (28%), a follow-up DXA was performed. Correlations with growth, changes in body composition and effects of illness duration and menstruation were examined. Size adjusted DXA standard deviation scores were calculated for total body (TB) less head bone mineral content (TBLH-BMC) and lumbar spine bone mineral apparent density (LS-BMAD).

RESULTS

Mean (range) bone area (BA) for height centile was 27.1 (0-97), and mean lean mass for height centile was 28.8 (0-95) at baseline. Mean (range) LS BMAD was -1.0 (-2.6, 0.8) SDS at first and - 1.2 (-3.0, -0.2) at second DXA (p = 0.023). On follow up, lean mass for height increased from 27th centile (0, 75) to 40th centile (0, 70) (p = 0.006), and fat mass for height increased from 55 g/cm to 67 g/cm (11.3, 124.2) (p < 0.001). Duration of illness was the only negative predictor of LS BMAD (p < 0.0001). Change in height SDS was the only positive predictor of change in TBLH-BMC (r = 0.384, p = 0.037), and change in LS BMAD (r-0.934, p < 0.0001). Of 68 patients who had VFA, 4 (5.9%) had a mild vertebral fracture.

CONCLUSION

Bones are smaller and less dense in childhood/adolescent AN compared to healthy adolescents. Although there are significant gains in lean mass and fat mass, over time, BMAD SDS decreases slightly. Improvement in BMAD SDS is related to improvement in height SDS.

The Association between Weight Gain/Restoration and Bone Mineral Density in Adolescents with Anorexia Nervosa: A Systematic Review

Background: Reduced bone mineral density (BMD) is one of the most frequent medical complications of anorexia nervosa (AN). The purpose of this paper was to conduct a systematic review of the association between weight gain/restoration and BMD in adolescents with AN. Methods: Literature searches, study selection, method, and quality appraisal were performed independently by two authors, and data were collated using a narrative approach. Results: Of the 1156 articles retrieved, 19 studies met the inclusion criteria, and their analysis revealed four main findings. First, six studies reported that weight gain and restoration are associated with BMD stabilization after one year of follow-up from baseline. Second, seven studies with longer follow-up periods (≈16 months) reported significant improvements in BMD measures. Third, one study showed that normalization of BMD can be achieved after ≈30-month follow-up of normal-weight maintenance. Fourth, another study showed that male adolescents with AN who achieve weight gain but remain underweight may experience further BMD loss, unlike their weight-restored counterparts (BMI ≥ 19 kg/m²), who show a significant increase in BMD and bone mineral accrual rates that double those of healthy male adolescents. The first two findings can be considered robust, as they are supported by strong evidence. The third and fourth findings, however, derive from single studies and therefore require further confirmation. Conclusion: The literature supports weight gain as an effective strategy for promoting BMD increase in adolescents with AN. However, this process is slow, and improvements do not become detectable until ≈16-month follow-up.

State of the art systematic review of bone disease in anorexia nervosa

OBJECTIVE

Low bone mineral density (BMD) is a known consequence of anorexia nervosa (AN) and is particularly concerning during adolescence, a critical time for bone accrual. A comprehensive synthesis of available data regarding impaired bone health, its determinants, and associated management strategies in AN is currently lacking. This systematic review aims to synthesize information from key physiologic and prospective studies and trials, and provide a thorough understanding of impaired bone health in AN and its management.

METHOD

Search terms included "anorexia nervosa" AND "bone density" for the period 1995-2015, limited to articles in English. Papers were screened manually based on journal impact factor, sample size, age of participants, and inclusion of a control group. When necessary, we included seminal papers published before 1995.

RESULTS

AN leads to low BMD, impaired bone quality and increased fracture risk. Important determinants are low lean mass, hypogonadism, IGF-1 deficiency, and alterations in other hormones that impact bone health. Weight gain and menses restoration are critical for improving bone outcomes in AN. Physiologic estrogen replacement as the transdermal patch was shown to increase bone accrual in one study in adolescent females with AN; however, residual deficits persist. Bisphosphonates are potentially useful in adults with AN.

DISCUSSION

To date, evidence suggests that the safest and most effective strategy to improve bone health in AN is normalization of weight with restoration of menses. Pharmacotherapies that show promise include physiologic estradiol replacement (as the transdermal estradiol patch), and in adults, bisphosphonates. Further studies are necessary to determine the best strategies to normalize BMD in AN.

Anorexia Nervosa and Its Associated Endocrinopathy in Young People

Anorexia nervosa (AN) is a condition of severe undernutrition associated with adaptive changes in many endocrine axes. These changes include hypogonadotropic hypogonadism, acquired growth hormone resistance with low insulin-like growth factor 1 (IGF-1) levels, hypercortisolemia, altered secretion of adipokines and appetite-regulating hormones, and low bone mineral density (BMD). Bone health is impaired subsequent to a low body mass index, decreased lean mass, and the endocrine changes described above. In addition to low areal BMD, AN is characterized by a decrease in volumetric BMD, changes in bone geometry, and reductions in strength estimates, leading to an increased risk for fracture. Weight restoration is essential for restoration of normal endocrine function; however, hypercortisolemia, high peptide YY levels, and ghrelin dynamics may not completely normalize. In some patients, hypogonadotropic hypogonadism persists despite weight restoration. Weight gain and menstrual recovery are critical for improving bone health in AN; however, residual deficits may persist. Physiologic estrogen replacement using transdermal, but not oral, estrogen increases bone accrual in adolescents with AN, while bisphosphonates improve BMD in adults. Recombinant human IGF-1 and teriparatide have been used in a few studies as bone anabolic therapies. More data are necessary to determine the optimal therapeutic strategies for low BMD in AN.

Searching for additional endocrine functions of the skeleton: genetic approaches and implications for therapeutics

Our knowledge of whole organism physiology has greatly advanced in the past decades through mouse genetics. In particular, genetic studies have revealed that most organs interact with one another through hormones in order to maintain normal physiological functions and the homeostasis of the entire organism. Remarkably, through these studies many unexpected novel endocrine means to regulate physiological functions have been uncovered. The skeletal system is one example. In this article, we review a series of studies that over the years have identified bone as an endocrine organ. The mechanism of action, pathological relevance, and therapeutic implications of the functions of the bone-derived hormone osteocalcin are discussed. In the last part of this review we discuss the possibility that additional endocrine functions of the skeleton may exist.

An overview of the metabolic functions of osteocalcin

A recent unexpected development of bone biology is that bone is an endocrine organ regulating a growing number of physiological processes. One of the functions regulated by bone through the hormone osteocalcin is glucose homeostasis. In this overview, we will explain why we hypothesized that bone mass and energy metabolism should be subjected to a coordinated endocrine regulation. We will then review the experiments that revealed the endocrine function of osteocalcin and the cell biology events that allow osteocalcin to become a hormone. We will also illustrate the importance of this regulation to understand whole-body glucose homeostasis in the physiological state and in pathological conditions. Lastly, we will mention epidemiological and genetic evidence demonstrating that this function of osteocalcin is conserved in humans.

An overview of the metabolic functions of osteocalcin

A recent unexpected development of bone biology is that bone is an endocrine organ contributing to the regulation of a number of physiological processes. One of the functions regulated by bone through osteocalcin, an osteoblast specific hormone, is glucose homeostasis. In this overview, we explain the rationale why we hypothesized that there should be a coordinated endocrine regulation between bone mass and energy metabolism. We then review the experiments that identified the endocrine function of osteocalcin and the cell biology events that allow osteocalcin to become a hormone. We also demonstrate the importance of this regulation to understand whole-body glucose homeostasis in the physiological state and in pathological conditions. Lastly we discuss the epidemiological and genetic evidence demonstrating that this function of osteocalcin is conserved in humans.

The role of leptin in regulating bone metabolism

Leptin was initially best known for its role in energy homeostasis and regulation of energy expenditure. In the past few years we have realized that leptin also plays a major role in neuroendocrine regulation and bone metabolism. Here, we review the literature the indirect and direct pathways through which leptin acts to influence bone metabolism and discuss bone abnormalities related to leptin deficiency in both animal and human studies. The clinical utility of leptin in leptin deficient individuals and its potential to improve metabolic bone disease are also discussed. We are beginning to understand the critical role leptin plays in bone metabolism; future randomized studies are needed to fully assess the potential and risk-benefit of leptin's use in metabolic bone disease particularly in leptin deficient individuals.

Assessment of gene expression in peripheral blood using RNAseq before and after weight restoration in anorexia nervosa

We examined gene expression in the blood of six females with anorexia nervosa (AN) before and after weight restoration using RNAseq. AN cases (aged 19-39) completed clinical assessments and had blood drawn for RNA at hospital admission (T1,<~75% ideal body weight, IBW) and again at discharge (T2,≥ ~ 85% IBW). To examine the relationship between weight restoration and differential gene expression, normalized gene expression levels were analyzed using a paired design. We found 564 genes whose expression was nominally significantly different following weight restoration (p<0.01, 231 increased and 333 decreased). With a more stringent significance threshold (false discovery rate q<0.05), 67 genes met criteria for differential expression. Of the top 20 genes, CYP11A1, C16orf11, LINC00235, and CPA3 were down-regulated more than two-fold after weight restoration while multiple olfactory receptor genes (OR52J3, OR51L1, OR51A4, and OR51A2) were up-regulated more than two-fold after weight restoration. Pathway analysis revealed up-regulation of two broad pathways with largely overlapping genes, one related to protein secretion and signaling and the other associated with defense response to bacterial regulation. Although results are preliminary secondary to a small sample size, these data provide initial evidence of transcriptional alterations during weight restoration in AN.

[Evaluation of bone mineral density in female adolescents with eating disorders]

OBJECTIVE

To evaluate lumbar bone mineral density (BMD) in girls with eating disorders in the beginning of the treatment, at six months, and after one year of treatment.

SUBJECTS AND METHODS

This prospective study involved 35 female adolescents with AN or EDNOS treated during one year. Lumbar (L1-L4) bone mineral density by DXA was performed in the beginning of treatment, at six months, and after one year of treatment.

RESULTS

There was improvement in weight, length, BMI, bone age (p < 0.001), and 70% of the adolescents with secondary amenorrhea had their menstrual cycles restored. However, the Z-score of lumbar BMD did not show differences during one year of follow-up (p = 0.76).

CONCLUSION

The recovery of BMD does not occur together with the restoration of hypothalamic-pituitary-gonadal axis.

Bone metabolism in anorexia nervosa: molecular pathways and current treatment modalities

Eating disorders are associated with a multitude of metabolic abnormalities which are known to adversely affect bone metabolism and structure. We aimed to comprehensively review the literature on the effects of eating disorders, particularly anorexia nervosa (AN), on bone metabolism, bone mineral density (BMD), and fracture incidence. Furthermore, we aimed to highlight the risk factors and potential management strategies for patients with eating disorders and low BMD. We searched the MEDLINE/OVID (1950-July 2011) and EMBASE (1980-July 2011) databases, focussing on in vitro and in vivo studies of the effects of eating disorders on bone metabolism, bone mineral density, and fracture incidence. Low levels of estrogen, testosterone, dehydroepiandrosterone, insulin-like growth factor-1 (IGF-1), and leptin, and high levels of cortisol, ghrelin, and peptide YY (PYY) are thought to contribute to the 'uncoupling' of bone turnover in patients with active AN, leading to increased bone resorption in comparison to bone formation. Over time, this results in a high prevalence and profound degree of site-specific BMD loss in women with AN, thereby increasing fracture risk. Weight recovery and increasing BMI positively correlate with levels of IGF-1 and leptin, normalisation in the levels of cortisol, as well as markers of bone formation and resorption in both adolescent and adult patients with AN. The only treatments which have shown promise in reversing the BMD loss associated with AN include: physiologic dose transdermal and oral estrogen, recombinant human IGF-1 alone or in combination with the oral contraceptive pill, and bisphosphonate therapy.

Ghrelin: central and peripheral implications in anorexia nervosa

Increasing clinical and therapeutic interest in the neurobiology of eating disorders reflects their dramatic impact on health. Chronic food restriction resulting in severe weight loss is a major symptom described in restrictive anorexia nervosa (AN) patients, and they also suffer from metabolic disturbances, infertility, osteopenia, and osteoporosis. Restrictive AN, mostly observed in young women, is the third largest cause of chronic illness in teenagers of industrialized countries. From a neurobiological perspective, AN-linked behaviors can be considered an adaptation that permits the endurance of reduced energy supply, involving central and/or peripheral reprograming. The severe weight loss observed in AN patients is accompanied by significant changes in hormones involved in energy balance, feeding behavior, and bone formation, all of which can be replicated in animals models. Increasing evidence suggests that AN could be an addictive behavior disorder, potentially linking defects in the reward mechanism with suppressed food intake, heightened physical activity, and mood disorder. Surprisingly, the plasma levels of ghrelin, an orexigenic hormone that drives food-motivated behavior, are increased. This increase in plasma ghrelin levels seems paradoxical in light of the restrained eating adopted by AN patients, and may rather result from an adaptation to the disease. The aim of this review is to describe the role played by ghrelin in AN focusing on its central vs. peripheral actions. In AN patients and in rodent AN models, chronic food restriction induces profound alterations in the « ghrelin » signaling that leads to the development of inappropriate behaviors like hyperactivity or addiction to food starvation and therefore a greater depletion in energy reserves. The question of a transient insensitivity to ghrelin and/or a potential metabolic reprograming is discussed in regard of new clinical treatments currently investigated.

Effect of catch-up growth by various dietary patterns and resveratrol intervention on bone status

Catch-up growth (CUG) after food restriction can increase the risks for insulin resistance-related diseases, and to our knowledge, no previous studies have addressed how bone is influenced by CUG when refeeding diet content differs. The objective of this study was to investigate the bone status resulting from CUG induced by varying refeeding dietary patterns, and to assess the potential influencing factors and the effect of resveratrol on bone status during CUG. Experimental rats were randomly divided into five groups: normal chow (NC) group; CUG group (CUG, containing two subgroups, respectively, refeeding with normal chow or high-fat diet); high-fat diet (HF) group; and resveratrol intervention groups (CUGE and HFE). Bone parameters were detected by dual-energy X-ray absorptiometry. Serum concentrations of tumor necrosis factor (TNF)- α, body weight and food intake were also recorded. Our results showed that food restriction induced a significant decrease in bone parameters. Eight-week CUG by normal chow had a greater degree of improvement in bone mineral density than high-fat diet, and even returned to normal level similar to NC. Bone parameters were elevated in varying degrees in the HF group compared with the NC group. In the resveratrol intervention groups, bone parameters significantly increased. Furthermore, bone parameters were inversely related with serum TNF- α concentrations, but showed positive correlation with body weight. In conclusion, the study shows that CUG can partially reverse the deleterious effects of caloric restriction on bone health, especially in the refeeding with normal chow group. Moreover, resveratrol has a protective effect on bone status during the period of CUG. Serum TNF- α levels and body weight also seem to play an important role in regulating bone parameters.

Effects of exercise on bone mass in young women with anorexia nervosa

PURPOSE

The response of bone to exercise in women with anorexia nervosa (AN) is unclear. We investigated the associations between bone mineral density (BMD) and exercise performed while ill and while recovered in women with a history of AN.

METHODS

A cross-sectional study was conducted with 141 women with AN (85 ill; 56 recovered), aged 17-40 yr. BMD at the lumbar spine (LS), femoral neck (FN), and total body (TB) was measured by dual-energy x-ray absorptiometry. Life History Calendar and Minnesota Leisure Time Physical Activity interviews were used to collect lifetime illness and exercise histories (amount and bone loading type). Average hours per week of each of moderate (MOD) and high (HI) bone loading exercise were determined for three illness phases: "before ill," "while ill," and "while recovered." Participants were categorized into four exercise groups for each phase: MOD-ONLY, HI-ONLY, BOTH, and NEITHER (reference group). Weight-adjusted BMD z-scores were compared in the exercise groups by multivariable linear regression, adjusting for illness duration and severity, and exercise during the other illness phases.

RESULTS

In ill participants, MOD-ONLY "while ill" had lower BMD at LS (β = -0.69, 95% confidence interval (CI) = -1.02 to -0.05) and TB (β = -0.73, 95% CI = -1.31 to -0.15) than the NEITHER group. In recovered participants, HI-ONLY "while recovered" had higher BMD at FN (β = 0.95, 95% CI = 0.15-1.75) and TB (β = 0.79, 95% CI = 0.07-1.51) than the NEITHER group.

CONCLUSIONS

The effect of exercise on bone in AN patients is dependent on both the type of mechanical loading and the phase of illness during which it was performed. Excessive moderate loading exercise while ill may put patients at higher risk of low bone mass, but high bone loading activities may provoke bone accrual during recovery.

Caloric restriction leads to high marrow adiposity and low bone mass in growing mice

The effects of caloric restriction (CR) on the skeleton are well studied in adult rodents and include lower cortical bone mass but higher trabecular bone volume. Much less is known about how CR affects bone mass in young, rapidly growing animals. This is an important problem because low caloric intake during skeletal acquisition in humans, as in anorexia nervosa, is associated with low bone mass, increased fracture risk, and osteoporosis in adulthood. To explore this question, we tested the effect of caloric restriction on bone mass and microarchitecture during rapid skeletal growth in young mice. At 3 weeks of age, we weaned male C57Bl/6J mice onto 30% caloric restriction (10% kcal/fat) or normal diet (10% kcal/fat). Outcomes at 6 (n = 4/group) and 12 weeks of age (n = 8/group) included body mass, femur length, serum leptin and insulin-like growth factor 1 (IGF-1) values, whole-body bone mineral density (WBBMD, g/cm(2)), cortical and trabecular bone architecture at the midshaft and distal femur, bone formation and cellularity, and marrow fat measurement. Compared with the normal diet, CR mice had 52% and 88% lower serum leptin and 33% and 39% lower serum IGF-1 at 6 and 12 weeks of age (p < .05 for all). CR mice were smaller, with lower bone mineral density, trabecular, and cortical bone properties. Bone-formation indices were lower, whereas bone-resorption indices were higher (p < .01 for all) in CR versus normal diet mice. Despite having lower percent of body fat, bone marrow adiposity was elevated dramatically in CR versus normal diet mice (p < .05). Thus we conclude that caloric restriction in young, growing mice is associated with impaired skeletal acquisition, low leptin and IGF-1 levels, and high marrow adiposity. These results support the hypothesis that caloric restriction during rapid skeletal growth is deleterious to cortical and trabecular bone mass and architecture, in contrast to potential skeletal benefits of CR in aging animals.

Physiologic and behavioral indicators of energy deficiency in female adolescent runners with elevated bone turnover

BACKGROUND

Female adolescent runners have an elevated prevalence of low bone mass for agemdashan outcome that may be partially due to inadequate energy intake.

OBJECTIVE

The objective was to evaluate diet, menstrual history, serum hormone concentrations, and bone mass in female adolescent runners with normal or abnormal bone turnover.

DESIGN

Thirty-nine cross-country runners (age: 15.7 plusmn 0.2 y) participated in the study, which included a 7-d dietary assessment with the use of a food record and daily 24-h dietary recalls; serum measures of insulin-like growth factor I, estradiol, leptin, parathyroid hormone, progesterone, triiodothyronine, 25-hydroxycholecalciferol, bone-specific alkaline phosphatase (BAP), and cross-linked C-telopeptides of type I collagen (CTX); an evaluation of height, weight, bone mass, and body composition with the use of dual-energy X-ray absorptiometry; and a questionnaire to assess menses and sports participation. Age- and sex-specific BAP and CTX concentrations of at least the 97th percentile and no greater than the third percentile, respectively, were considered abnormal.

RESULTS

All abnormal BAP and CTX concentrations fell within the elevated ( ge 97%) range. Runners with an elevated bone turnover (EBT) (n = 13) had a lower body mass, fewer menstrual cycles in the past year, lower estradiol and 25-hydroxycholecalciferol concentrations, and a higher prevalence of body mass index lt 10% for age, vitamin D insufficiency, amenorrhea, and low bone mass. Girls with EBT consumed less than the recommended amounts of energy and had a higher prevalence of consuming lt 1300 mg Ca than did those with normal bone turnover.

CONCLUSIONS

Runners with EBT had a profile consistent with energy deficiency. Nutritional support to increase energy, calcium intake, and 25-hydroxycholecalciferol concentrations may improve bone mineral accrual in young runners with EBT. This trial was registered at clinicaltrials.gov as NCT01059968.

Osteoporosis in anorexia nervosa

Anorexia nervosa is a condition associated with reduced bone mass and increased bone fragility, for which there is no known effective treatment. Anorexia nervosa usually has its onset during adolescence, the critical time when peak bone mass is accrued. Low bone mass is caused by reduced bone formation, as well as accelerated bone resorption. The etiology is multifactorial and includes poor nutrition, low bodyweight, sex hormone deficiency and hypercortisolism. Weight gain and resumption of menses is accompanied by some improvement in bone mass, but may not restore it to normal levels. Oral estrogen-replacement therapy is not effective in increasing bone mass in this disorder. The bisphosphonates, used in conjunction with nutritional rehabilitation and weight gain, have shown promise, but concerns about safety have limited their use. The aim of this article is to highlight recent recommendations regarding the assessment of fracture risk in children and adolescents, summarize the evidence for low bone mass and increased fracture risk in anorexia nervosa, and discuss approaches to the management of low bone mass in this disorder.

Bone mineral density in partially recovered early onset anorexic patients - a follow-up investigation

BACKGROUND AND AIMS

There still is a lack of prospective studies on bone mineral development in patients with a history of early onset Anorexia nervosa (AN). Therefore we assessed associations between bone mass accrual and clinical outcomes in a former clinical sample. In addition to an expected influence of regular physical activity and hormone replacement therapy, we explored correlations with nutritionally dependent hormones.

METHODS

3-9 years (mean 5.2 +/- 1.7) after hospital discharge, we re-investigated 52 female subjects with a history of early onset AN. By means of a standardized approach, we evaluated the general outcome of AN. Moreover, bone mineral content (BMC) and bone mineral density (BMD) as well as lean and fat mass were measured by dual-energy x-ray absorptiometry (DXA). In a substudy, we measured the serum concentrations of leptin and insulin-like growth factor-I (IGF-I).

RESULTS

The general outcome of anorexia nervosa was good in 50% of the subjects (BMI >/= 17.5 kg/m2, resumption of menses). Clinical improvement was correlated with BMC and BMD accrual (chi2 = 5.62/chi2 = 6.65, p = 0.06 / p = 0.036). The duration of amenorrhea had a negative correlation with BMD (r = -.362; p < 0.01), but not with BMC. Regular physical activity tended to show a positive effect on bone recovery, but the effect of hormone replacement therapy was not significant. Using age-related standards, the post-discharge sample for the substudy presented IGF-I levels below the 5th percentile. IGF-I serum concentrations corresponded to the general outcome of AN. By contrast, leptin serum concentrations showed great variability. They correlated with BMC and current body composition parameters.

CONCLUSIONS

Our results from the main study indicate a certain adaptability of bone mineral accrual which is dependent on a speedy and ongoing recovery. While leptin levels in the substudy tended to respond immediately to current nutritional status, IGF-I serum concentrations corresponded to the individual's age and general outcome of AN.

Leptin-mediated neuroendocrine alterations in anorexia nervosa: somatic and behavioral implications

Hypoleptinemia is a key endocrinological feature of anorexia nervosa (AN). Several symptoms in acute AN are related to the low circulating leptin levels including amenorrhea and semi-starvation-induced hyperactivity. The drop in leptin levels results from the loss of fat mass; once leptin levels fall below specific thresholds the hypothalamic-pituitary-gonadal and -thyroid axes are down-regulated; in contrast, the hypothalamic-pituitary-adrenal axis is up-regulated. Hypoleptinemia is the major signal underlying both somatic and behavioral adaptations to starvation. Because the mechanisms involved in this adaptation are similar in rodents and humans, rodent models can be used to investigate the relevant central pathways which underly the respective starvation-induced symptoms. During therapeutically induced weight gain, leptin levels can intermittently increase above normal concentrations. This hyperleptinemia could predispose to renewed weight loss.

Adolescent eating disorders: definitions, symptomatology, epidemiology and comorbidity

Eating disorders have morbidity and mortality rates that are among the highest of any mental disorders and are associated with significant functional impairment. This article provides an up-to-date review on recent developments and expanding knowledge in adolescent anorexia nervosa, bulimia nervosa, and related disorders. It covers diagnoses and assessment, recognition of typical symptoms, medical and psychiatric comorbidities, and current trends in epidemiology.

Predictors of recovery of ovarian function after weight gain in subjects with amenorrhea related to restrictive eating disorders

OBJECTIVE

The aim of the present study was to investigate the anthropometric and endocrine characteristics of subjects with amenorrhea related to eating disorders after weight recovery, in order to identify factors connected with the resumption of menses.

METHODS

Clinical data, body composition parameters and serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), thyroid-stimulating hormone (TSH), free triiodothyronine, free thyroxine, cortisol, leptin and insulin were assessed in two groups of young women classified according to menstrual status after weight rehabilitation: 43 subjects who displayed persistent amenorrhea and 34 who resumed menses. Univariate and multivariate logistic regression analyses were used to examine the relationships between the different parameters and menstrual recovery.

RESULTS

The patients who resumed menses had low initial weight and BMI, and a greater difference between current and initial BMI (DeltaBMI), than those with amenorrhea. No differences were observed in lean mass, body fat or bone density between the two groups. Moreover, the reduction in FSH and the increase in LH, insulin and leptin emerged as significant predictors of menstrual recovery. Increased DeltaBMI and insulin continued to be positive predictors in the multivariate analysis.

CONCLUSION

Following weight rehabilitation, the individual's metabolic set point before weight loss and the current insulin levels appear significant in predicting the reactivation of reproductive function.