Bone metabolism and osteopenia in eating disorders

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.

Low Energy Availability in Exercising Women: Historical Perspectives and Future Directions

Research on the health of female athletes has developed substantially over the past 50 years. This review aims to provide an overview of this research and identify directions for future work. While early cross-sectional studies focused primarily on menstruation, research has progressed to now encompass hormonal changes, bone health and lipid profiles. The seminal work of Loucks and colleagues distinguished that these health concerns were due to low energy availability (LEA) rather than exercise alone. LEA occurs when the body has insufficient energy available to meet the needs of training and normal physiological functioning. While there appears to be agreement that LEA is the underlying cause of this syndrome, controversy regarding terminology has emerged. Originally coined the female athlete triad (Triad), some researchers are now advocating the use of the term relative energy deficiency in sport (RED-S). This group argues that the term Triad excludes male athletes who also have the potential to experience LEA and its associated negative impact on health and performance. At present, implications of LEA among male athletes are poorly understood and should form the basis of future research. Other directions for future research include determination of the prevalence and long-term risks of LEA in junior and developmental athletes, and the development of standardised tools to diagnose LEA. These tools are required to aid comparisons between studies and to develop treatment strategies to attenuate the long-term health consequences of LEA. Continued advances in knowledge on LEA and its associated health consequences will aid development of more effective prevention, early detection and treatment strategies.

High prevalence of vitamin D deficiency and insufficiency in adolescent inpatients diagnosed with eating disorders

OBJECTIVE

Previous studies assessing vitamin D status in adolescents with eating disorders showed inconsistent results. The aim of the current study was to assess vitamin D status in a large cohort of adolescent inpatients with eating disorders and its relation to bone mineral density (BMD) and depression.

METHOD

25-Hydroxyvitamin D (25OHD), calcium, phosphorus, and alkaline phosphatase levels as well as BMD and depression were assessed on admission in 87 inpatients (aged 16 ± 2 years, females = 81) with eating disorders [anorexia nervosa (AN) = 64; bulimia nervosa (BN) = 5; eating disorders not otherwise specified-binge/purge type (EDNOS-B/P) = 18].

RESULTS

Mean 25OHD levels were 24.1 ± 7.5 ng/ml (25.0 ± 7.6, 25.4 ± 9.9, and 22.0 ± 9.9 ng/ml in patients with AB, BN, and EDNOS-B/P, respectively). Vitamin D deficiency (<15 ng/ml) was found in 7.8% of the patients, and insufficiency (15-20 ng/ml) in 22.2%. Only 16.7% had levels >32 ng/ml, considered optimal by some experts. No associations were found between 25OHD levels and BMD or comorbid depression. 25OHD levels during winter were significantly lower than summer levels (p < .001). Mean lumbar spine BMD z-score in patients with AN and EDNOS-B/P type was low (-1.5 ± 1.1) and correlated with body mass index standard deviation score (p = .03).

DISCUSSION

Adolescents with eating disorders show a high prevalence of vitamin D deficiency and insufficiency. Given the risk of osteoporosis in this population, 25OHD levels found in this group may not offer optimal bone protection. Vitamin D levels should be routinely checked and supplementation should be administered as required.

Harmful effects of functional hypercortisolism: a working hypothesis

Functional hypercortisolism (FH) is caused by conditions able to chronically activate hypothalamic-pituitary-adrenal axis and usually occurs in cases of major depression, anorexia nervosa, bulimia nervosa, alcoholism, diabetes mellitus, simple obesity, polycystic ovary syndrome, obstructive sleep apnea syndrome, panic disorder, generalized anxiety disorder, shift work, and end-stage renal disease. Most of these states belong to pseudo-Cushing disease, a condition which is difficult to distinguish from Cushing's syndrome and characterized not only by biochemical findings but also by objective ones that can be attributed to hypercortisolism (e.g., striae rubrae, central obesity, skin atrophy, easy bruising, etc.). This hormonal imbalance, although reversible and generally mild, could mediate some systemic complications, mainly but not only of a metabolic/cardiovascular nature, which are present in these states and are largely the same as those present in Cushing's syndrome. In this review we aim to discuss the evidence suggesting the emerging negative role for FH.

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.

The clinical biochemistry of anorexia nervosa

In anorexia nervosa, under-nutrition and weight regulatory behaviours such as vomiting and laxative abuse can lead to a range of biochemical problems. Hypokalaemia is the most common electrolyte abnormality. Metabolic alkalosis occurs in patients who vomit or abuse diuretics and acidosis in those misusing laxatives. Hyponatraemia is often due to excessive water ingestion, but may also occur in chronic energy deprivation or diuretic misuse. Urea and creatinine are generally low and normal concentrations may mask dehydration or renal dysfunction. Abnormalities of liver enzymes are predominantly characterized by elevation of aminotransferases, which may occur before or during refeeding. The serum albumin is usually normal, even in severely malnourished patients. Amenorrhoea is due to hypogonadotrophic hypogonadism. Reduced concentrations of free T4 and free T3 are frequently reported and T4 is preferentially converted to reverse T3. Cortisol is elevated but the response to adrenocorticotrophic hormone is normal. Hypoglycaemia is common. Hypercholesterolaemia is a common finding but its significance for cardiovascular risk is uncertain. A number of micronutrient deficiencies can occur. Other abnormalities include hyperamylasaemia, hypercarotenaemia and elevated creatine kinase. There is an increased prevalence of eating disorders in type 1 diabetes and the intentional omission of insulin is associated with impaired metabolic control. Refeeding may produce electrolyte abnormalities, hyper- and hypoglycaemia, acute thiamin depletion and fluid balance disturbance; careful biochemical monitoring and thiamin replacement are therefore essential during refeeding. Future research should address the management of electrolyte problems, the role of leptin and micronutrients, and the possible use of biochemical markers in risk stratification.

Endocrine manifestations of eating disorders

CONTEXT

The endocrinopathies associated with eating disorders involve multiple systems and mechanisms designed to preserve energy and protect essential organs. Those systems that are most affected are in need of significant energy, such as the reproductive and skeletal systems. The changes in neuropeptides and in the hypothalamic axis that mediate these changes also receive input from neuroendocrine signals sensitive to satiety and food intake and in turn may be poised to provide significant energy conservation. These adaptive changes are described, including the thyroid, GH, and cortisol axes, as well as the gastrointestinal tract.

EVIDENCE ACQUISITION

Articles were found via PubMed search for both original articles and reviews summarizing current understanding of the endocrine changes of eating disorders based on peer review publications on the topic between 1974 and 2009.

CONCLUSION

The signals that control weight and food intake are complex and probably involve multiple pathways that appear to have as a central control the hypothalamus, in particular the medial central area. The hypothalamic dysfunction of eating disorders provides a reversible experiment of nature that gives insight into understanding the role of various neuropeptides signaling nutritional status, feeding behavior, skeletal repair, and reproductive function.

Female athlete triad

Although eating disorders have received much attention over the last few years in athletics, its prevalence was not always well appreciated. Over the years, professional organizations began to pay close attention to the effects of eating disorders, and with this heightened awareness, professionals as well as the general public began to recognize eating disorders as a major problem in our society. In the early 1990s, the American College of Sports Medicine (ACSM) convened the Task Force on Women's Issues in Seattle, Washington . During this conference, members of the ACSM discussed issues related to females and athletics with specific attention to eating disorders, amenorrhea, and osteoporosis. They collectively called these pathologies the Female Athlete Triad (Triad) and hence coined the phrase in 1993. Since the publication, much time and effort has been devoted towards research and understanding of the Triad. In trying to understand this complicated problem, one must grasp the concept that the three pathologies are interrelated and difficult to explain without the influence of any of the other components.

Variables for the prediction of femoral bone mineral status in American women

INTRODUCTION

A reliable procedure for identifying persons at risk for osteoporosis and subsequent fracture is needed so that preventive measures may be initiated.

MATERIAL AND METHODS

Participants included 7,532 women, ages 20 and older, surveyed in the National Health and Nutrition Examination Survey III (NHANES, 1988-1994). Influences of race, body composition, exercise, alcohol intake, smoking status, as well as the effect of nutritional intake of calcium, phosphorus, magnesium, iron, zinc, sodium, and potassium on bone mineral density (BMD) were assessed.

RESULTS

Advancing age, low body weight, low exercise expenditure, and smoking were significant predictors for low BMD. Nutritional variables examined were not significant in the predictive models.

CONCLUSIONS

The absence of calcium from the predictive models indicates the need for re-evaluation of the current recommended intake levels of this nutrient. A greater emphasis on factors such as exercise and achieving adequate weight is recommended.

DISCUSSION

Providing women with the knowledge of their risk for low BMD may influence lifestyle behaviors, which may ultimately result in the prevention of bone injury.

Age-related differences in hormonal and nutritional impact on lean anorexia nervosa bone turnover uncoupling

INTRODUCTION

In anorexia nervosa (AN) patients osteoporosis occurs within a framework of multiple hormonal abnormalities as a result of bone turnover uncoupling, with decreased bone formation and increased bone resorption. The aim of study was to evaluate the hormonal and nutritional relationships with both of these bone remodeling compartments and their eventual modifications with age.

PATIENTS AND MEASUREMENTS

In a cohort of 115 AN patients (mean BMI:14.6 kg/m2) that included 60 mature adolescents (age: 15.5-20 years) and 55 adult women (age: 20-37 years) and in 28 age-matched controls (12 mature adolescents and 16 adults) we assessed: bone markers [serum osteocalcin, skeletal alkaline phosphatase (sALP), C-telopeptide of type I collagen (sCTX) and tartrate-resistant acid phosphatase type 5b (TRAP 5b)], nutritional markers [ body mass index (BMI, fat and lean mass), hormones (free tri-iodothyronine (T3), free T4, thyroid stimulating hormone (TSH), luteinizing hormone (LH), follicle stimulating hormone (FSH), 17 beta estradiol, free testosterone index (FTI), dehydroepiandrosterone (DHEAS), insulin-like growth factor 1 (IGF-1), growth hormone (GH) and cortisol], plasma methoxyamines (metanephrine and normetanephrine) and calcium metabolism parameters [parathyroid hormone (PTH), Ca, vitamin D3].

RESULTS

Osteocalcin reached similar low levels in both AN age subgroups. sCTX levels were found to be elevated in all AN subjects and higher in mature adolescents than in adult AN (11,567+/-895 vs. 8976+/-805 pmol/l, p<0.05). sALP was significantly lower only in mature adolescent AN patients, while there were no significant differences in the levels of TRAP 5b between AN patients and age-matched control groups. Osteocalcin correlated with sCTX in the control subjects (r=0.65) but not in the AN patients, suggesting the independent regulation of these markers in AN patients. Osteocalcin levels strongly correlated with freeT3, IGF-I, 17 beta estradiol and cortisol, while sCTX correlated with IGF-I, GH and cortisol in both age subgroups of the AN patients. Other hormones or nutritional parameters displayed age-related correlations with bone markers, leading to different stepwise regression models for each age interval. In mature adolescent AN patients, up to 54% of the osteocalcin variance was due to BMI, cortisol and 17 beta estradiol, while 54% of the sCTX variance was determined by GH. In adult subjects, freeT3 and IGF-I accounted for 64% of osteocalcin variance, while 65% of the sCTX variance was due to GH, FTI and methoxyamines.

CONCLUSIONS

We suggest a more complex mechanism of AN bone uncoupling that includes not only "classical" influence elements like cortisol, IGF-I, GH or 17 beta estradiol but also freeT3, catecholamines and a "direct" hormone-independent impact of denutrition. Continuous changes of these influences with age should be considered within the therapeutic approach to AN bone loss.

A prospective study of changes in bone turnover and bone density associated with regaining weight in women with anorexia nervosa

Anorexia nervosa (AN) is a condition of self-induced weight loss, associated with an intense fear of gaining weight. Previous studies have shown that bone density may increase with regaining and maintaining normal weight; however, relatively little is known about the changes in bone metabolism that occur during weight restoration. We describe the effect of weight restoration and maintenance of weight over 1 year on bone mineral density (BMD) and bone turnover. We recruited women from the eating disorders services at the South West London and St George's Mental Health NHS Trust, and the Priory and Charter Nightingale Hospitals in London, UK. Details of their AN, fracture history, menstrual history and exercise were obtained by interview and case note review. Morning samples of blood and second void urine were taken for biochemical analysis. BMD was measured by DXA at the lumbar spine (LS), femoral neck (FN), distal radius (RD) and total body bone mineral content (BMC). Patients then entered the treatment program, which includes re-feeding, dietary education and psychotherapy. Over a period of 42 months, we recruited 55 women who agreed to participate in this study and underwent baseline investigations. Of these, 15 (27%) subjects achieved and then maintained their target weight for the duration of the study. At baseline for all subjects (n=55) estradiol levels were lower than the normal reference ranges (both follicular and luteal phases) in 91% of the women. Bone specific alkaline phosphatase (BSAP) concentrations were lower than the premenopausal reference range in 55% of women, and urinary deoxypyridinoline (DPD) was above the premenopausal reference range in 78% of women. Baseline lumbar spine BMD was positively related to BMI (Pearson's r=0.29, P=0.04) and inversely related to bone turnover markers: urinary DPD (Pearson's r=-0.39, P=0.01 and serum BSAP (Pearson's r=-0.3, P=0.06). The 15 patients who regained and maintained weight were followed-up for a mean duration of 69 weeks (SD 7.3, range 54 to 84 weeks). Mean BMI increased from 14.2 (1.7) to 20.2 (0.77) kg/m2 and remained stable throughout follow-up. Menstruation resumed in 8 of the 15 women. Total body BMC and LS BMD increased significantly over the duration of follow-up (by 4.3% each), but FN BMD and distal radius remained stable. Lumbar spine bone area also increased significantly, whereas FN and distal radius did not. These changes were associated with a significant increase in BSAP (P=0.01), and a non-significant trend for a decrease in DPD (P=0.10). Our findings suggest that when women are at low body weight they are in a hypo-estrogenic state, which is associated with imbalance of bone turnover (high bone resorption and low bone formation). This is reversed with weight gain and persists as target weight is maintained and is associated with increases in BMC and BMD.

Secondary osteoporosis

Secondary osteoporosis occurs as a consequence of various lifestyle factors (eg, eating disorders, smoking, alcoholism), disease processes (eg, endocrinopathies, gastrointestinal tract disease, hepatobiliary disease), and treatment regimens that comprise corticosteroids or chemotherapeutic agents. Some of the disease entities underlying secondary osteoporosis may be clinically silent and identified only during evaluation for documented osteoporosis. The pathogenesis of osteoporosis in these settings is typically multifactorial. The loss of bone may be direct or indirect but ultimately is related to altered osteoblast or osteoclast function. Causes of secondary osteoporosis should especially be investigated in men at all ages and in premenopausal women with atraumatic fractures. In addition, patients with known risk factors should be evaluated. Early recognition and intervention are essential to prevent further loss of bone mass and to prevent fragility fractures.

The skeletal effects of glucocorticoid excess override those of orchidectomy in mice

Hypogonadism has been implicated as a contributing factor in glucocorticoid-induced osteoporosis, but evidence for this is limited. Hypogonadism and glucocorticoid excess both cause bone loss, but the cellular mechanisms responsible are distinct. Loss of gonadal steroids causes an increase in bone remodeling by up-regulating osteoblastogenesis and osteoclastogenesis. Glucocorticoid excess, conversely, suppresses remodeling by down-regulating osteoblastogenesis and osteoclastogenesis. Nonetheless, both conditions increase osteoblast apoptosis and decrease osteoclast apoptosis, and both cause bone loss due to an undersupply of osteoblasts relative to the need for cavity repair. To investigate their interactions, we compared the effects of orchidectomy, glucocorticoid excess, or both combined in mice. After 28 d, serum unbound testosterone concentration and seminal vesicle weight were not diminished when prednisolone was administered alone. Vertebral bone mineral density and compression strength decreased to the same extent in animals receiving prednisolone or after orchidectomy, but the changes were not additive. Orchidectomy induced the expected up-regulation of osteoblast and osteoclast progenitors, but these changes were prevented in orchidectomized mice simultaneously receiving glucocorticoids. Likewise, the increase in cancellous osteoid, osteoblasts, osteoclasts, bone formation, and activation frequency caused by orchidectomy were prevented by prednisolone. The prevalence of osteoblast apoptosis increased in the mice receiving prednisolone or after orchidectomy, but the increases were not additive. These data demonstrate that hypogonadism does not occur in or contribute to glucocorticoid-induced osteoporosis and that the adverse skeletal effects of glucocorticoid excess override those of orchidectomy.

Lower bone mass detected at femoral neck and lumbar spine in lower-weight vs normal-weight small-boned women

Sixty-one nonsmoking, healthy, young, menstruating women aged 18 to 30 years generally considered at peak skeletal bone mass were screened for diseases and drugs known to adversely affect bone mineral density (BMD). Anthropometric measures, BMD of the lumbar spine (LS) and femoral neck (FN), exercise time, selected nutrient, and energy intake were compared. The women were categorized by frame size and body mass index (BMI), with the upper range for normal weight (NW) being BMI 23.0 to 25.9 (n=30) and lower weight (LW) being BMI 16.0-19.9 (n=31). Multivariate t tests, Pearson correlations, and independent sample t tests were used for statistical analysis. Ten of 21 in the LW group, all with small frames, had varying degrees of low BMD of the LS and/or FN. The amount of exercise time was greater in the NW group. Energy and nutrient intakes did not differ significantly between groups.

Recognition and management of eating disorders in the dental office

Extensive damage to the teeth may result from self-induced vomiting. Recognition of the oral signs of eating disorders is a responsibility of dental care providers. Young women with BN and AN may seek dental care before seeking medical treatment because they are concerned about their appearance. Early identification of oral changes by the dental practitioner and referral to medical and psychiatric therapists can reduce the risk of further physical damage to the body or greater loss of tooth surface enamel. Home care instructions will be followed when the reasons for timing of toothbrushing, rinsing after vomiting, and use of fluoride are explained. Careful selection of beverages and snacks will help reduce the risk of further erosion and dental caries. Comprehensive dental procedures should not be undertaken until significant improvement in vomiting behavior or complete recovery has occurred.

Osteoporosis in anorexia nervosa: prevention and treatment

BACKGROUND

Osteoporosis is a very prevalent complication of anorexia nervosa. In contrast to the many other medical complications of anorexia, osteoporosis and its sequelae of fractures, kyphosis, and pain may persist regardless of the overall treatment outcome.

DISCUSSION

Traditional well-proven therapies for postmenopausal osteoporosis are not as effective against osteoporosis in anorexia nervosa. Therefore, clinicians who treat these patients must become increasingly vigilant about osteoporosis in regards to preventive, diagnostic, and treatment strategies.

Correlates of low bone density in females with anorexia nervosa

The objectives were to delineate those factors which correlate with low bone density in patients with anorexia nervosa and in turn to predict those at greatest risk for osteopenia.

DESIGN

Bone density was evaluated by dual energy x-ray absorptiometry in 28 postmenarchal females with anorexia nervosa who had never received hormonal therapy. Bone density results were correlated with specific historical and physical factors utilizing descriptive statistics, scatter plots, and the Spearman correlation coefficient.

RESULTS

Mean age was 18.6 years, mean age at menarche was 12.9 yrs, mean length of illness was 19.8 months and mean duration of amenorrhea was 13.4 months. Mean % ideal body weight was 84% at the time of bone density, 75% at minimum weight and 100% at maximum weight. Mean lumbar spine bone density was -1.69 standard deviations from the norm; mean lateral spine bone density was -1.45 standard deviations from the norm; mean femoral neck of the hip bone density was -1.18 standard deviations from the norm. There was a strong negative correlation between duration of amenorrhea and bone density at the lumbar spine (r = -0.50, p < .01) and a mild correlation at the lateral spine (r = -0.49, p < 0.05) and femoral neck (r = -0.41, p < 0.05). There was also a strong negative correlation between length of illness and bone density at the lumbar spine (r = -0.53, p < 0.01) and lateral spine (r = -0.77, p < 0.0001), and a mild correlation with the femoral neck (r = -0.48, p < 0.05). Scatter plots of lumbar bone density versus duration of amenorrhea, and versus length of illness clearly showed not only that longer duration of amenorrhea and longer length illness correlated to bone loss, but also strikingly that within a short time of being ill and amenorrheic, significant bone loss was seen. Age, and age at menarche correlated mildly with osteopenia at the lateral spine; age correlated mildly with osteopenia at the femoral neck as well. There was a trend for minimum BMI to correlate with osteopenia at the lateral spine. There were no correlations of bone density with % IBW at bone density, minimum % IBW, maximum % IBW, change in % IBW, BMI at the time of the bone density, maximum BMI or change in BMI.

CONCLUSIONS

Low bone density, especially in the lumbar spine, correlated with both a longer duration of amenorrhea and longer length of illness, but not with other factors, in our patients with anorexia nervosa. As many of these patients, even those with a short duration of illness and amenorrhea, were osteopenic, it is advisable to continue to perform bone density studies in all patients with anorexia nervosa, on both a clinical and research basis.

Spaceflight affects bone formation in rhesus monkeys: a histological and cell culture study

Using analyses of iliac crest cell and tissue, back-scattered electron imaging, and biochemical techniques, we characterized the effects of a 14-day spaceflight (Bion 11) on bone structure and bone formation in two 3- to 4-yr-old male rhesus monkeys compared with eight age-matched Earth-control monkeys. We found that postflight bone volume was 35% lower than preflight values in flight monkeys. This was associated with reduced osteoid (-40%) and mineralizing (-32%) surfaces and decreased bone formation rate (-53%). Moreover, flight monkeys exhibited trends to lower values of mineralization profile in iliac bone (back-scattered electron imaging) and to decreased osteocalcin serum levels (P = 0.08). The initial number of trabecular bone cells yielded in cultures did not differ in flight and control animals before or after the flight. However, osteoblastic cell proliferation was markedly lower in postflight vs. preflight at 9 and 14 days of culture in one flight monkey. This study suggests that a 14-day spaceflight reduces iliac bone formation, osteoblastic activity, and/or recruitment in young rhesus monkeys, resulting in decreased trabecular bone volume.

Osteoporosis and anorexia nervosa: relative role of endocrine alterations and malnutrition

BACKGROUND AND AIM

Anorexia nervosa (AN) is a psychiatric disorder characterised by self-induced starvation or a very reduced caloric intake, and frequently by severe life-threatening protein calory malnutrition. Its physiological consequences include amenorrhea, estrogen deficiency and osteoporosis. Osteoporosis may develop as a consequence of a lack of estrogens, low calcium or vitamin D intake, hypercortisolemia or the duration of the illness. The aim of this study was to identify the best endocrinological and nutritional indicators of bone density.

SUBJECTS AND METHODS

The study involved 49 young females with AN and malnutrition and 24 age-matched normal controls in whom AN had been excluded on the basis of a clinical evaluation using DSM IV criteria. We studied bone density in early osteopenia, a condition in which the potential risk of fractures is certainly high and traditionally related to a variety of endocrinological and nutritional factors.

RESULTS

Bone density was significantly lower in the AN than the control group in all of the examined bone districts: bone mineral density (BMD) spine 0.89 +/- 0.19 vs 1.27 +/- 0.2 (p<0.0001), BMD neck 0.75 +/- 0.14 vs 1.08 +/- 0.17 (p<0.001), BMD Ward 0.74 +/- 0.17 vs 1.12 +/- 0.11 (p<0.0001). Non-significant differences were found in the patients who had undergone previous estrogen medication. Body mass index (BMI) correlated with bone density, but caloric and calcium intake were not significant predictors. IGF-1, a known nutritionally dependent trophic bone factor, was significantly reduced in our patients but did not correlate with BMD. Like other authors, we found a close correlation between lean body mass and BMD in neck and spine. Physical exercise, urinary free cortisol osteocalcin and type I collagen-telopeptide (NTX) did not significantly correlate with the degree of osteopenia.

CONCLUSIONS

Our data suggest the importance of nutritional factors (particularly lean body mass and BMI) in determining bone mass, and the relatively limited importance of endocrinological factors with the exception of the duration of amenorrhea as an indirect indicator of endocrinological status.

Osteoporosis: prevention and treatment in anorexia nervosa

One of the most serious and potentially permanently disabling medical complications of anorexia nervosa is osteoporosis, which greatly increases the long-term risk of bone fractures. The decreased bone density in patients with anorexia nervosa (AN) is due to the many effects on bone metabolism of amenorrhea, reduced levels of insulin growth factor-1 (IGF-1), high cortisol levels and weight loss. Although estrogen replacement therapy is clearly efficacious in preventing postmenopausal osteoporosis, its efficacy in AN is uncertain. Clinicians caring for patients with AN need to be aware of this because, despite such therapy, there may be an inexorable decline in bone mineral density in what is a relatively young group of patients. AN frequently has its onset during adolescence, when peak bone mass is normally reached, and an anorectic episode in youth may permanently impair skeletal integrity and lead to debilitating fractures and pain. It is important to recognise this formidable risk, counsel AN patients about the longterm and possibly permanent sequelae of low body weight, use densitometry to screen for bone loss and treat it accordingly. The most effective treatment is still early weight restoration and the resumption of menses.

Clinical and biochemical determinants of bone metabolism and bone mass in adolescent female patients with anorexia nervosa

Among pathologies prevalent in western societies, anorexia nervosa has increased over the last decade. Its effects on bone mass need to be defined, and prognostic factors, either clinical or biochemical, could aid clinicians in individual patient management. To determine which clinical and/or biochemical parameters could be related to bone mass status in adolescent female anorexia nervosa patients, 73 female patients were classified according to different stages of their illness and studied in terms of clinical and biochemical parameters and bone densitometric mineral content at lumbar spine. Patients (age 17.2 +/- 1.7 y, mean +/- SD) with Tanner pubertal stage 5, regular menstruation for more than 3 mo before the onset of secondary amenorrhea, and diagnosed with anorexia nervosa were consecutively studied and classified in three clinical situations: I) active phase (34 patients): undernourished and amenorrheic; II) weight recovered but still amenorrheic (20 patients); III) fully recovered (19 patients). Clinical data were recorded at the time of bone density measurement, concomitant with blood sample extraction for study of IGF-I, IGF-binding protein 3 (IGFBP-3), IGFBP-1, estradiol, sex hormone-binding globulin, dehydroepiandrosterone sulfate, prealbumin, amino-terminal propeptide of procollagen III, osteocalcin, bone alkaline phosphatase, carboxy-terminal propeptide of procollagen I, amino-terminal propeptide of procollagen I, carboxy-terminal telopeptide of collagen I, 25-OH-vitamin D, 1,25(OH)(2)-vitamin D, and parathormone. In addition, a 24-h urine collection was made for cortisol, GH, deoxypyridinoline, amino-terminal telopeptide of collagen I, and calcium and creatinine content analysis. IGF-I, estradiol, and biochemical bone formation markers were higher and IGFBP-1, sex hormone-binding globulin, and biochemical bone resorption markers were lower in the weight-recovered stages (stages II and III) compared with the active phase (stage I). Bone formation markers correlated positively with body mass index SD score and IGF-I, whereas bone resorption markers correlated negatively with body mass index SD score and estradiol. Although no statistically significant differences regarding lumbar spine bone mineral density SD score values were recorded among the three stages of the illness, the proportion of osteopenic patients was clearly lower among stage III patients. The actual bone mineral density was inversely related to the duration of amenorrhea and directly related to duration of postmenarcheal menses before amenorrhea. In addition, a subset of osteopenic patients (five of 19) in the fully clinically recovered group with accelerated bone turnover was identified. Normal circulating estrogen level exposure time predicts actual bone mineral density at lumbar spine in young adolescent anorexia nervosa patients. In addition to psychiatric and nutritional interventions, estrogen-deprivation periods must be shortened to less than 20 mo. Patients remaining osteopenic at full clinical recovery require additional follow-up studies.

Hypercorticism blunts circadian variations of osteocalcin regardless of nutritional status

Anorexia nervosa (AN) and Cushing's syndrome (CS) are both responsible for osteoporosis. The mechanisms leading to osteoporosis in AN include hypogonadism, nutritional depletion, and in some cases hypercorticism. Osteocalcin circulating level is a serum marker of osteoblastic activity that follows a circadian rhythm (OCR). Serum osteocalcin is decreased in both CS and AN and can be increased with treatment. In this study we analyzed the influence of combined cortisol and nutritional status on osteocalcin levels and its circadian rhythm in these two different models of hypercorticism, one nutritionally replete (CS) and one nutritionally deplete (AN), and we evaluated the effects of their treatment (surgical cure and weight gain, respectively). Before treatment, osteocalcin levels were lower in CS (n = 16) and AN (n = 42) than in controls and in the AN patient subgroup with hypercorticism (n = 13) compared to those without (n = 29). OCR was absent in CS and in AN patients with hypercorticism, whereas their circadian cortisol cycle was maintained. In CS, successful surgical treatment increased osteocalcin levels (n = 5) and restored OCR. In AN, weight gain (n = 13) induced a significant decrease in cortisol levels in hypercortisolic AN patients, and restored normal osteocalcin levels and OCR. In conclusion, we found that hypercorticism was associated with a decrease in osteocalcin levels in nutritionally replete or deplete patients and that OCR was more affected by cortisol levels than by cortisol cycle.

Dietary restraint, exercise, and bone density in young women: are they related?

PURPOSE

Women with high scores for dietary restraint have been found to have higher 24-h urinary cortisol excretion and a higher prevalence of subclinical ovulatory disturbances, both of which may be risk factors for bone loss. The purpose of this study was to explore relationships between dietary restraint and bone health in regularly menstruating young women.

METHODS

62 women (age: 21.7 +/- 2.5 yr) had body composition and total body and lumbar spine bone mineral density (BMD) and content (BMC) assessed using dual-energy x-ray absorptiometry. Dietary restraint was assessed using the restraint subscale from the Three-Factor Eating Questionnaire: 29 women had low restraint (LR; restraint score 0--5), 33 had high restraint (HR; restraint score 13--21). Exercise (h x wk(-1)) was assessed by questionnaire on two occasions.

RESULTS

LR and HR women were similar in age and body composition (fat mass = 15.0 +/- 4.7 kg, lean mass = 40.9 +/- 4.9 kg), but HR women exercised more (3.4 +/- 1.7 vs 2.2 +/- 1.8 h x wk(-1), P < 0.05). Exercise was correlated with BMD and BMC, and when it was included as a covariate, total body BMC was significantly lower in HR than LR women. In multiple regression analysis, weekly hours of exercise and restraint score were significant predictors of total body BMD and BMC.

CONCLUSION

The observations of this cross-sectional study suggest that high levels of cognitive dietary restraint, or associated factors such as higher cortisol, may attenuate the positive effects of exercise on bone in young women.

Position of the American Dietetic Association: nutrition intervention in the treatment of anorexia nervosa, bulimia nervosa, and eating disorders not otherwise specified (EDNOS)

More than 5 million Americans suffer from eating disorders. Five percent of females and 1% of males have anorexia nervosa, bulimia nervosa, or binge eating disorder. It is estimated that 85% of eating disorders have their onset during the adolescent age period. Although Eating Disorders fall under the category of psychiatric diagnoses, there are a number of nutritional and medical problems and issues that require the expertise of a registered dietitian. Because of the complex biopsychosocial aspects of eating disorders, the optimal assessment and ongoing management of these conditions appears to be with an interdisciplinary team consisting of professionals from medical, nursing, nutritional, and mental health disciplines (1). Medical Nutrition Therapy provided by a registered dietitian trained in the area of eating disorders plays a significant role in the treatment and management of eating disorders. The registered dietitian, however, must understand the complexities of eating disorders such as comorbid illness, medical and psychological complications, and boundary issues. The registered dietitian needs to be aware of the specific populations at risk for eating disorders and the special considerations when dealing with these individuals.

Osteoporosis in young people. Research and treatment in eating disorders

We still have much to learn about BMD problems in eating disorders. Much progress has been made in the past 10 years; most clinicians and many patients and their families are now aware of the problem. More research is crucial, however, the authors suggest focusing on three areas: 1. Treatment and prevention: Such studies are difficult to conduct for similar reasons to the difficulties in conducting treatment trials of therapy for AN. First, the relative rarity of the condition makes it difficult to recruit subjects; second, drop-out rates are higher because of ambivalence; and third, the population is heterogeneous both in terms of symptoms and cause. 2. Better understanding of bone turnover in AN. More studies are needed to examine turnover of bone in patients with AN using biochemical markers. In particular, prospective studies are needed to examine the effects of refeeding, weight gain, and treatments such as calcium supplementation. 3. Long-term course of bone density. It would be particularly instructive to examine this in individuals with a short or long history of AN. It would also be useful to study women approaching menopause who had an episode of AN in their teens or early twenties compared with women who were of normal weight during this period.

Eating disorders: a role for dipeptidyl peptidase IV in nutritional control

Dipeptidyl peptidase IV (DPP IV), a serine protease with broad tissue distribution and known activity in serum, has been postulated to modulate nutrition control by modification or inactivation of peptide hormones operating in the enteroinsular axis. We hypothesized that changes of DPP IV activity in serum are related to the nutrition status of patients with eating disorders. Serum DPP IV activity was measured in 52 patients (28 with anorexia nervosa and 24 with bulimia nervosa) in four consecutive weekly analyses. Simultaneously, the number of CD26 (DPP IV)-positive peripheral blood lymphocytes was counted. The same analyses were carried out in 28 healthy female volunteers. In week 1 and throughout the observation period, DPP IV activity in the sera of patients with anorexia nervosa and, to a lesser extent, those with bulimia nervosa was elevated in comparison to that of healthy controls (week 1: means = 92.8 U/L for anorexia-nervosa patients and 89.3 U/L for bulimia-nervosa patients versus 74.7 U/L for healthy control subjects, P = 0.014; weeks 1-4: 91.8 U/L for anorexia-nervosa patients and 86.2 U/L for bulimia-nervosa patients versus 77.6 U/L for healthy controls, P < 0.001). We assume that the increase in DPP IV serum activity will increase the turnover of distinct peptide hormones with known effects on nutrition control and susceptibility to degradation by DPP IV. The potential impact of an increase in DPP IV activity in serum on satiety and nutrition control contributes to previously reported implications for immune function.

Estrogen replacement therapy in the management of osteopenia related to eating disorders

The effect of hormone replacement therapy on the bone mineral content of hypoestrogenic subjects depends on the pathogenesis of the disease as well as on the dosage and route of administration. This is particularly true in hypoestrogenism related to eating disorders. We present a longitudinal study of 26 young women with diet-induced amenorrhea compared with a group of subjects with POF. The study protocol included the quantification of weight loss, the endocrine profile (follicle-stimulating hormone, luteinizing hormone, prolactin, E2, FT3, FT4, thyroid-stimulating hormone, and cortisol), the evaluation of markers of bone turnover (GLA, OSTK-PR, ALP, OHP, and DPYR), and spinal bone density by DEXA at observation and after weight recovery. No hormone replacement therapy was administered. Mean BMD and Z scores before and after recovery do not differ significantly; OHP and DPYR appear significantly higher during basal evaluation, whereas GLA and ALP do not. Data on the impact of oral contraceptive use on bone mineral density are controversial. We particularly discuss the question of long-term treatment with 20 micrograms ethinyl estradiol pills on peak bone mass acquisition during adolescence.

Bone mineral status in adolescent girls: effects of eating disorders and exercise

PURPOSE

To compare whole-body, lumbar, total spine, and pelvis bone mineral density (BMD), body mass index (BMI), body composition, energy expenditure for physical activity, and dietary intake of adolescents, aged 16-22 years.

METHODS

Three study groups included 25 girls with histories of eating disorderd, 25 girls with no histories of eating diso rders who exercised < or = 7 hours/week, and 15 girls with no history of eating disorders who exercised > 7 hours/week. Bone mineral density was measured by dual-energy x-ray absorptiometry (DEXA), body composition by bioelectric impedance and DEXA, energy expenditure by Personal Activity Computer, nutrient intake by 4-day dietary recalls/records, and BMI by measures of height/weight. General linear models, LSM +/- SEM, Student's t-tests, and correlation analyses were used to determine group differences.

RESULTS

No significant differences in whole-body, spinal, and pelvis BMD were found among the three groups. Mean body fat (percent) was significantly higher (p =.0001) for the group with histories of eating disorders than other groups. Dietary intakes of adolescents with histories of eating disorders were significantly lower for energy (p =.0001), fat (p =.0001), calcium (p =.0007), vitamin D (p =.0180), and zinc (p =.0057) than those without eating disorder histories who exercised </= 7 hours/week.

CONCLUSION

Except for body fat (percent), measures of BMD, energy expenditure, and BMI were not significantly different among groups. Our data suggest that with full recovery from eating disorders, teenage girls can achieve normal bone mass and body composition.

Use of hormone replacement therapy to reduce the risk of osteopenia in adolescent girls with anorexia nervosa

PURPOSE

To assess how commonly hormone replacement therapy (HRT) and other measures are prescribed for the treatment of osteopenia in children and adolescents with anorexia nervosa (AN).

METHODS

A self-administered questionnaire was distributed and completed by allopathic and osteopathic physician members of the Society for Adolescent Medicine at its 1998 annual meeting. The questionnaire was also mailed and E-mailed between March 1998 and February 1999. Descriptive statistics included percentages and measures of central tendency.

RESULTS

The questionnaire was completed by 394 of the 1029 physicians surveyed (38.3%). Of the 268 respondents who treated patients with AN under the age of 18 years, 77.6% prescribed HRT. The decision to prescribe HRT was influenced by patient's age but not by bone mineral status. Among those who prescribed HRT, additional therapies included increased caloric intake (89.4%), weight gain (82.2%), increased calcium intake (84.1%), a change in exercise patterns (59.1%), and vitamin D supplementation (37.0%). Only 59 (22.0%) did not use HRT as a treatment modality. One-third of nonprescribers cited the lack of evidence of efficacy of HRT in preventing osteopenia. More recent medical graduates were less likely to prescribe HRT.

CONCLUSIONS

This survey suggests that practitioners caring for adolescent females with AN commonly prescribe HRT for the treatment of osteopenia despite the paucity of evidence demonstrating that it effectively prevents or reverses bone loss associated with this disorder.

Prevalence of cutaneous manifestations in 200 patients with eating disorders

BACKGROUND

Eating disorders are increasing and show a variety of symptoms. They mainly include anorexia nervosa (AN), bulimia nervosa (BN), and eating disorders not specified (EDNOS). They predominate in females and represent an important danger, especially in teenagers. In serious cases, they may be life-threatening. Objective To determine the prevalence of cutaneous findings in patients with eating disorders and to compare the results with those found in the literature.

METHODS

An observational, transverse, and prospective study was performed. Two hundred patients of recent admission to ALUBA (association that fights against BN and AN), a psychiatric unit for eating disorders, were included: 122 BN; 62 AN; 16 EDNOS.

RESULTS

Patients with eating disorders show dermatologic manifestations (alopecia, xerosis, hypertrichosis, caries, nail fragility) that are secondary to starvation. Russell's sign, seen as calluses on the dorsal aspect of the hands, is a consequence of self-induced vomiting and the local trauma of the superior incisors. This sign represents a compensatory behavior to overeating and predominates in the BN group.

CONCLUSION

The recognition of dermatologic signs could be of immense value and could lead to the early diagnosis and treatment of these eating disorders.

Weight gain reverses bone turnover and restores circadian variation of bone resorption in anorexic patients

OBJECTIVE

The present study was conducted in order to describe the variations and circadian rhythm of biochemical markers of bone remodelling at baseline and after weight gain in patients with anorexia nervosa (AN).

SUBJECTS

We studied 9 women (mean age 21 years, range: 16-30) with established AN who remained amenorrhoeic during the study and with a low body mass index (BMI) after refeeding and 6 female controls (mean age 20 years, range, 18-24 and BMI: 20.6 +/- 1.1 kg/m2). Refeeding was not associated with any other intervention or treatment, especially oestrogen replacement or hormonal contraception. Serum levels of oestradiol remained below 70 pmol/l before and after refeeding.

MEASUREMENTS

During the study, PTH and 25-hydroxyvitamin D measurements were performed. Markers of bone formation: serum intact osteocalcin (iBGP) and serum intact BGP + fragments (iBGP+F) and markers of bone resorption: urine C-teloptide of type I collagen (uCTX) and serum C-telopeptide ofvtype 1 collagen (s-CTX) were measured.

RESULTS

At baseline, PTH and 25 OH-vitamin D concentrations were within the normal range in AN patients and no significant variation was observed after refeeding. Bone formation markers were found to be significantly different at baseline between AN patients and controls. After refeeding, iBGP and iBGP+F levels increased by 172% and 154%, respectively, to values no different from controls. Intact BGP and iBGP+F exhibited a significant circadian variation in controls (P < 0.05 and P < 0.002, respectively), whereas we did not find any such circadian rhythm in AN patients. After refeeding no significant circadian variation was observed; however, iGBP+F tended to peak in early morning and exhibited a nadir in the afternoon. At baseline, sCTX was 2-fold higher in AN patients than in controls. After weight gain sCTX decreased significantly and reached control values. Refeeding induced a non-significant 40% decrease in uCTX. We found positive correlations between uCTX and the 24-h mean value of sCTX levels (r2 = 0.93, P < 0.0001) and between uCTX and the mean value of sCTX peak levels at 0800 h (r2 = 0.65, P < 0.0003). Serum CTX exhibited a significant circadian variation in controls (P < 0.001) with a peak at 0800 h and a nadir at 1600 h with a 60% decrease between peak and nadir values. We found that anorexia nervosa suppressed the sCTX circadian variation which was restored by refeeding. We found a significant non-linear relationship between BMI and sCTX/iBGP ratio in AN (r2 = 0.6, P < 0.0001), thus illustrating the influence of nutritional status on bone remodelling.

CONCLUSIONS

In this study we found that weight gain, related to refeeding only, reversed the anorexia nervosa-induced uncoupling of bone remodelling and restored circadian variation of a bone resorption marker.

Alterations in expression and in serum activity of dipeptidyl peptidase IV (DPP IV, CD26) in patients with hyporectic eating disorders

The notion that patients with eating disorders maintain a functional immunosurveillance in spite of severe malnutrition has attracted researchers for years. Dipeptidyl peptidase IV (DPP IV), a serine protease with broad tissue distribution and known activity in serum, operates in the cascade of immune responses. Membrane-bound DPP IV expressed on lymphocytes, also known as the leucocyte antigen CD26, is considered to participate in T-cell activation. We hypothesized that the activity of DPP IV in serum and expression of CD26 in lymphocytes may be altered in patients with eating disorders. Serum DPP IV activity and the number of CD26 (DPP IV)-positive peripheral blood lymphocytes were measured in 34 patients [anorexia nervosa (AN): n = 11, bulimia (B): n = 23] in four consecutive weekly analyses. In addition, the expression of CD25 (interleukin-2 receptor alpha chain) was evaluated to estimate the degree of T-cell activation. The same analyses were carried out in healthy female volunteers (HC, n = 20). CD2-CD26-positive cells were reduced in patients compared with healthy controls [mean 40.2% (AN) and 41.1% (B) versus 47.4% (HC), P < 0.01], while the DPP IV activity in serum was elevated [mean 108.4 U/l (AN) versus 91.1 U/l (B) and 80.3 U/l (HC), P < 0.01]. The potential implications of our observations on, and beyond, immune function are discussed.

Long-term fracture risk among women with anorexia nervosa: a population-based cohort study

OBJECTIVE

To determine if fractures represent an important problem for women with anorexia nervosa who may fail to achieve peak bone mass and may experience premature bone loss from decreased estrogen levels.

PATIENTS AND METHODS

In this population-based retrospective cohort study, we identified 208 Rochester, Minn, residents that were first diagnosed as having anorexia nervosa between 1935 and 1989, whose subsequent fractures were documented in contemporary medical records and compared with expected numbers of fractures (standardized incidence ratios [SIRs]).

RESULTS

Subjects were followed up for 2689 person-years during which time 45 patients suffered 88 fractures. Fracture risk was increased among the 193 women (SIR, 2.9; 95% confidence interval, 2.0-3.9) as well as the 15 men (SIR, 3.4; 95% confidence interval, 1.1-7.9). The cumulative incidence of any fracture at 40 years after the diagnosis of anorexia nervosa was 57%. Fractures of the hip, spine, and forearm were late complications, occurring on average 38, 25, and 24 years, respectively, after diagnosis.

CONCLUSION

Young women with anorexia nervosa are at increased risk of fractures later in life. Greater attention should be paid to the skeletal health of these individuals.

A variation in Bone Alkaline Phosphatase levels that correlates positively with bone loss and normal levels of aminoterminal propeptide of collagen I in girls with anorexia nervosa

Anorexia nervosa (AN) is a very extended pathology among adolescent girls nowadays. These patients show a high degree of osteopenia; hence, study of their bone remodelling is of great interest. Serum bone alkaline phosphatase (bAP) and aminoterminal propeptide of procollagen I (PINP) provide good sensitivity in the analysis of bone alterations in postmenopausal osteoporosis. The aim of this study was to compare the usefulness of bAP and PINP in the study of bone remodelling in AN, and their possible correlation with the degree of osteopenia in this pathology. In order to help in the interpretation of the results, levels of the beta-isomer of urinary carboxyterminal propeptide of collagen I (beta-CTX) have also been included. Serum bAP (IRMA) Tandem R-Ostase, Hybritech), PINP (RIA, Orion Diagnostica) and CTX (CrossLaps ELISA, Osteometer) were determined in 41 girls with AN, aged 18.5+/-2.2 years (mean+/-SD) and in 31 healthy control women, aged 19+/-2.3 years. Bone mineral density (BMD) in lumbar spine was measured by DEXA in the AN group. We found that 41 of the 43 patients had BMD z-scores under -2. No significant differences were found in the levels of serum bAP nor in PINP and beta-CTX levels between controls and patients, although values in the AN group were highly variable. All the BMD z-score values were negative, and their absolute value correlates positively with bAP (P = 0.0279) and almost with beta-CTX (P = 0.0921) but not with PINP (P = 0.4627). Bone AP correlates with PINP in control girls (P = 0.017), but not in the AN group (P = 0.3573). Patients with AN were divided into three groups according to their levels of bAP: low (I), normal (II) or high (III). Patients with the highest bAP levels also presented the highest increase in bone resorption, according to their beta-CTX levels, and the highest degree of osteopenia. However, values of PINP were similar in the three groups of patients. The bAP/beta-CTX ratios in subgroups I, II and III of AN patients were 0.035, 0.065 and 0.073, a finding that suggests that bAP is not indicating the real degree of bone mineralization in these patients, because it is a contradiction that the formation/resorption ratio should be higher in the patients who have the highest bone loss. These results could suggest that bone loss in AN is produced by an increase in bone resorption (beta-CTX), without variations in bone matrix formation (PINP); bAP levels are a good marker in the follow-up of osteopenia degree, but not a real indicator of bone mineralization, a similar situation to that of osteomalacia.

Osteoporosis and eating disorders

Osteoporosis is a common complication of anorexia nervosa. Multiple factors increase risk, including decreased body weight and fat content, elevated cortisol levels, inadequate vitamin D and calcium intake, and amenorrhea and hypoestrogenemia. There is both decreased bone formation and increased bone resorption in the osteoporosis of anorexia nervosa. Treatment includes weight normalization and supplemental calcium and vitamin D. Unlike postmenopausal osteoporosis, estrogen replacement does not prevent or correct the osteoporosis that occurs in anorexia nervosa. Patients with bulimia nervosa or an eating disorder not otherwise specified may also be at risk of osteoporosis, especially if they have had a prior episode of anorexia nervosa.

Dissociation of bone turnover in anorexia nervosa

Biochemical markers were measured to assess bone turnover in a cross-sectional study of 43 patients with anorexia nervosa; 28 were at their first assessment (untreated) with a body mass index (BMI) (median interquartile range) of 13.3 (2) kg/m2. A second group of 15 patients undergoing treatment (treated) had a median BMI of 17.6 (2.8) kg/m2. The median, interquartile range of urinary deoxypyridinoline (DPyd), a bone resorption marker, was raised in both groups compared with an age-matched control population [DPyd = 17.8 (15.2), 17.5 (16.4) and 9.2 (4.0) nmol/mmol creatinine, respectively]. Serum type 1 collagen carboxyterminal propeptide (P1CP), a marker of bone formation, was similar to controls in the untreated patients [112 (29) and 112 (78.5) ng/ml, respectively], but was significantly raised in the treated patients [163 (219) ng/ml, P < 0.05]. A second group of 21 patients was followed prospectively, on admission and during 8 weeks of intensive inpatient care (BMI on admission and after 8 weeks was 13.0 (2) and 16.7 (3) kg/m2, respectively). The resorption marker, serum type 1 collagen carboxyterminal telopeptide (1CTP) was raised on admission and remained high during treatment. P1CP and osteocalcin levels were similar to control levels on admission but increased with treatment, and after 8 weeks were 40% and 63% higher respectively than on admission. These findings suggest that in untreated anorexia nervosa there was uncoupling of bone turnover as bone resorption markers were raised without a concomitant increase in bone formation markers. As the condition was treated and patients gained weight, the formation markers also increased, leading to a more balanced, although higher, bone turnover.

Compromised bone density 11.4 years after diagnosis of anorexia nervosa

This investigation evaluated bone density in 36 premenopausal women (mean +/- SD age = 29.5 +/- 8.4 years) an average of 11.4 years after diagnosis for anorexia nervosa. Twenty-nine women were aged 20-45 years, and seven were aged 16-19 years. Body composition, age of menarche, length of amenorrhea, estrogen exposure, and lumbar spine and proximal femur bone density were determined. Average appendicular bone density for those > or = 20 years was found to meet World Health Organization T score criteria for osteopenia: total femur T = -1.22 and femoral neck T = -1.33. The average total lumbar Z score for all 36 participants was -0.95, which was 90% of the mean for their age, and the mean Z scores for adolescent subjects were within 91% of the mean for their age (Z = -0.84). Years of estrogen exposure were correlated with lumbar mineral content (r = 0.50, p = 0.002). A modest but significant inverse relationship was observed between length of amenorrhea and femoral and lumbar bone density. The total proximal femur and trochanteric bone densities were best predicted, using stepwise regression, by the number of years after diagnosis and years of amenorrhea, respectively (R2 = 0.23, p = 0.02 and R2 = 0.21, p = 0.04). Lumbar density was best predicted by years of amenorrhea and current percent of ideal body weight (%IBW)(R2 = 0.25, p = 0.02). Length of amenorrhea, estrogen exposure, and %IBW independently contribute to axial and appendicular bone density. Because of risk for compromised bone density, women with a history of anorexia nervosa should be followed longitudinally to maximize premenopausal bone replacement.

What is the impact of osteoporosis?

A body of evidence points towards a close connection between susceptibility to fractures and osteoporosis. The incidence of osteoporotic fractures, both in absolute figures and in age-specific figures, has increased worldwide throughout this century. Although some reports show that the age-specific incidence is levelling-off, there will be a continuously increasing number of individuals with such fractures that will have implications from an economical point of view not only for the affected individual but for society as a whole. The outcome after such fractures, especially those of the hip, is by no means always favourable, partly due to insufficient results after orthopaedic treatment and partly due to an already high comorbidity. Therefore, trying to prevent osteoporotic fractures by non-pharmacological or pharmacological regimens is of utmost importance.

Stress injury to bone in the female athlete

Stress injury to bone exists on a continuum, involving mechanical as well as hormonal and nutritional factors. Risk factors for stress injury include genetics, female gender, white ethnicity, low body weight, lack of weightbearing exercise, intrinsic and extrinsic mechanical factors, amenorrhea, oligoamenorrhea, inadequate calcium and caloric intake, and disordered eating. Prevention of stress injury to bone involves maximizing peak bone mass in the pediatric, adolescent, and young adult age groups. Maintaining adequate calcium nutrition and caloric intake, exercise and hormonal balance are important preventive measures in the adult years for optimizing skeletal integrity and preventing fractures. There are no prospective longitudinal studies to date that demonstrate a treatment that will increase bone density in female athletes with hypothalamic hypoestrogenic amenorrhea or disordered eating that have low bone density. Advances in genetic research show promise for future preventive and treatment strategies. More research is needed in this area to determine other factors that may be contributing to bone loss in these individuals, as well as to assess other treatment options leading to improvements in bone density and integrity.