Investigation of osteopaenia in anorexia nervosa

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.

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

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

Menstrual dysfunction in anorexia nervosa

Amenorrhea is a hallmark sign of anorexia nervosa. Its cause is multifactorial and its resolution necessitates treatment of the underlying eating disorder. The neuroendocrine changes associated with menstrual abnormalities in underweight and weight recovered anorexia nervosa, recent research on osteopenia, and treatment recommendations are addressed.

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.

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.

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.

On exposure to anorexia nervosa, the temporal variation in axial and appendicular skeletal development predisposes to site-specific deficits in bone size and density: a cross-sectional study

Skeletal development is heterogeneous. Throughout growth, bone size is more maturationally advanced than the mineral being accrued within its periosteal envelope; before puberty, appendicular growth is more rapid than axial growth; during puberty, appendicular growth slows and axial growth accelerates. We studied women with differing age of onset of anorexia nervosa to determine whether this temporal heterogeneity in growth predisposed to the development of deficits in bone size and volumetric bone mineral density (vBMD), which varied by site and severity depending on the age at which anorexia nervosa occurred. Bone size and vBMD of the third lumbar vertebra and femoral neck were measured using dual-energy X-ray absorptiometry in 210 women aged 21 years (range, 12-40 years) with anorexia nervosa. Results were expressed as age-specific SDs (mean +/- SEM). Bone width depended on the age of onset of anorexia nervosa; when the onset of anorexia nervosa occurred (1) before 15 years of age, deficits in vertebral body and femoral neck width did not differ (-0.77+/-0.27 SD and -0.55+/-0.17 SD, respectively); (2) between 15 and 19 years of age, deficits in vertebral body width (-0.95+/-0.16 SD) were three times the deficits in femoral neck width (-0.28+/-0.14 SD; p < 0.05 comparing the deficits), (3) after 19 years of age, deficits in the vertebral body width (-0.49+/-0.26 SD; p = 0.05) were half that in women with earlier onset of anorexia nervosa. No deficit in bone width was observed at the femoral neck. Deficits in vBMD at the vertebra and femoral neck were independent of the age of onset of anorexia nervosa but increased as the duration of anorexia nervosa increased, being about 0.5 SD lower at the vertebra than femoral neck. We infer that the maturational development of a region at the time of exposure to disease, and disease duration, determine the site, magnitude, and type of trait deficit in anorexia nervosa. Bone fragility due to reduced bone size and reduced vBMD in adulthood is partly established during growth.

Bone size and volumetric density in women with anorexia nervosa receiving estrogen replacement therapy and in women recovered from anorexia nervosa

Anorexia nervosa is associated with bone loss during adulthood, but may also delay skeletal growth and mineral accrual during growth. We asked the following questions. 1) Is anorexia nervosa associated with reduced bone size and reduced volumetric bone mineral density (vBMD)? 2) Is estrogen replacement therapy (ERT) or recovery from anorexia nervosa associated with normal bone size and vBMD? Using dual-energy x-ray absorptiometry, we measured bone size and vBMD of the third lumbar vertebra and femoral neck in a cross-sectional study of 161 female patients: 77 with untreated anorexia nervosa, 58 with anorexia nervosa receiving ERT, 26 recovered from anorexia nervosa, and 205 healthy age-matched controls. Results were expressed as the SD or z-score (mean +/- SEM). Deficits in vertebral body and femoral neck width in untreated women were -1.0 +/- 0.1 and -0.3 +/- 0.1 SD (P < 0.001 and P < 0.05, respectively). Deficits in bone width were less in the ERT-treated women than in untreated women at the vertebral body (-0.6 +/- 0.1 SD; P < 0.001), but not at the femoral neck (-0.4 +/- 0.2 SD; P < 0.05). There were no significant deficits in vertebral body and femoral neck width in recovered women (both -0.3 +/- 0.2 SD; P = NS). In untreated women, vertebral and femoral neck vBMD were -1.6 +/- 0.1 and -1.1 +/- 0.1 SD, respectively (both P < 0.001), less severely reduced in ERT-treated women (-1.2 +/- 0.2 and -0.6 +/- 0.2 SD, respectively; both P < 0.001), and least reduced in recovered women (-0.6 +/- 0.1 and -0.5 +/- 0.2 SD; P < 0.01 and P < 0.05, respectively). After adjusting for differences in fat and lean mass, vertebral body and femoral neck width were no longer reduced in untreated, ERT-treated, and recovered women. Adjustment for body composition had little effect on group difference in vBMD. Bone fragility in anorexia nervosa is due to reduced bone size and reduced vBMD. Although causality cannot be inferred in cross-sectional studies, the data are consistent with the view that malnutrition may contribute to reduced bone size, whereas estrogen deficiency may reduce vBMD. The use of ERT early in disease is a reasonable component of management if the chance of recovery appears remote.

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.

Medical complications of anorexia nervosa

Anorexia nervosa is often characterized by progressive deterioration in many different organ systems. Most medical complications are the result of starvation and can be reversed with a well-planned refeeding program. While some of the complications of anorexia nervosa are predictable physiologic adaptations to the self-imposed starvation, many others are potentially life threatening. It is therefore incumbent upon all primary care physicians to become familiar with this disorder, because it is increasing in incidence and is commonly burdened by substantial chronicity and recidivism.

Persistent osteopenia after recovery from anorexia nervosa

OBJECTIVE

Osteopenia is a known complication of anorexia nervosa. Most studies have focused on the features of the illness which predict bone complications. The few reports on recovery have been conflicting, with some studies suggesting restoration of normal bone mass with recovery from anorexia nervosa, while others suggest that the improvement may only be partial. This is the first report of bone density in a long-term recovered group.

METHOD

We measured bone density in the hip and lumbar spine in 18 recovered women, using dual energy X-ray absorptiometry.

RESULTS

We found an unexpectedly high incidence of osteopenia, with 14 of 18 women affected. Duration of amenorrhea was the best predictor of reduced bone density. An index of the duration of recovery, relating it to the duration of illness, was also highly correlated with outcome.

DISCUSSION

Our findings have implications, both for the individual and for the economic burden to society. We suggest that the use of oral contraceptives in women recovering from anorexia nervosa needs further investigation. Additional longitudinal studies are clearly warranted.

Bone mineral metabolism in diet-induced amenorrhea

Spinal bone density of 41 girls with diet-induced amenorrhea (DA) was compared with that of the density of 22 subjects with premature ovarian failure (POF) of comparable age. The Z score values, as well as the estradiol levels, were not significantly different in the two groups. The duration of amenorrhea was significantly correlated to bone mass density in the DA population, especially when considering subjects with amenorrhea that had lasted longer than 20 months. A similar correlation between weight loss and BMD was evident. Although estradiol concentrations did not seem to be correlated to the Z score, FT3 and cortisol values exhibited, respectively, a negative and a positive correlation with spinal density. Cortisol seemed to act precociously, whereas FT3 acted later than cortisol.

Bone mineral density of eating disorder subgroups

OBJECTIVE

We tested nine hypotheses among eating disorder subgroups and a control group on spinal bone density and investigated the relationship of their spinal bone density with a critical fracture threshold and five clinical variables--age of onset, years ill, percentage of ideal body weight (IBW), months of amenorrhea, and hours per week of exercise.

METHOD

Dual photon absorptiometry measured spinal bone density.

RESULTS

Anorectic patients had significantly less spinal bone mass than bulimic patients with no history of anorexia nervosa or control patients. Eating disordered patients with past or present anorexia nervosa had significantly more spinal bone density values below a critical fracture threshold. Duration of amenorrhea and exercise significantly predicted spinal bone density.

DISCUSSION

Anorectic women were unlikely to reach their peak bone density, thus possibly developing osteoporosis later in life, and were likely to be at risk for nontraumatic spinal fractures. Predicting spinal bone density of anorectic women could be done by knowing their duration of amenorrhea and exercise.

Bone metabolism and osteopenia in eating disorders

Bone loss is a potentially debilitating condition in women with eating disorders. Complications may include failure to achieve peak bone mass, increased risk of premature fractures, and inability to reach the height potential. We therefore conducted a comprehensive evaluation of 58 women with anorexia nervosa (AN), bulimia (BUL) and anorexia/bulimia (AB), comparing bone mineral density (BMD) to physical parameters, biochemical indices, and markers for bone formation and resorption. BMDs were significantly lower in patients with AN than in those with AB and BUL, and overt osteopenia was uncommon in AB and BUL. Hypercortisolism was the best laboratory marker to assess the risk of osteopenia in patients with AN. However, there were no associated changes in bone formation or resorption parameters. No direct correlation was found between BMD and body mass index, estrogen deficiency, tubular reabsorption of phosphorus, serum vitamin D, PTH, BGP, or alkaline phosphatase levels. Although the prognosis for complete recovery to normal BMD is poor, treatment of the underlying depressive disorder, improvement in nutrition with increased weight, and spontaneous resumption of menses are associated with restoring bone health.

Effects of weight gain and resumption of menses on reduced bone density in patients with anorexia nervosa

The bone mineral density (BMD) of the lumbar vertebrae (L2-L4) and of the whole body were measured in cross-sectional and longitudinal studies in female patients with eating disorders, using dual photon absorptiometry before and after weight gain with or without resumption of menses. In the cross-sectional study, the low-body-weight anorectic patients, with or without bulimia nervosa, were found to have lower BMD of the lumbar vertebrae associated with severe weight loss, low physical activity, and earlier onset and longer duration of amenorrhea. In the longitudinal study, 11 patients attained subnormal body weight (70%SBW < or = approximately < 85% SBW), 10 patients attained normal body weight (> or = 85%SBW, 6 patients of them resumed regular menses) after treatment. The BMD of the lumbar vertebrae was found to increase with weight gain, but not to the control level. The BMD was further increased with the resumption of menses in patients with anorexia nervosa. These results suggest that resumption of menses, in addition to weight gain, is essential to normalize reduced bone mineral density.

Case study of the effects of prolonged and severe anorexia nervosa on bone mineral density

Among the most severe sequelae of anorexia nervosa (AN) are its skeletal complications. Young women who have AN during adolescence may not attain their expected peak skeletal mass, and may enter adulthood with reduced bone mineral density (BMD) and an increased risk of fracture. This case history describes a young woman with severe AN that included prolonged exposure to both low body weight and amenorrhea. BMD measurement during the acute stage of her illness revealed severe osteopenia. Six years after recovery from AN, follow-up studies demonstrated only modest gains in BMD, with measurements for the hip and lumbar spine that are greater than 2 SDs below the age-matched mean.

The medical complications of anorexia nervosa

The physical complications of anorexia nervosa are common and can be life threatening, but psychiatrists and the increasing number of non-medical therapists involved in treatment programmes often overlook these complications. Cardiovascular complications are the most common, and the most likely to result in fatalities, particularly in those patients who vomit, purge or abuse diuretics, because of the electrolyte abnormalities induced. Osteoporosis is an early and perhaps irreversible consequence of severe weight loss. Further, there are dangers in rapid intravenous hyperalimentation.

Osteoporosis and normal weight bulimia nervosa--which patients are at risk?

This study assesses the degree of bone mineral loss in women with active DSM IIIR bulimia nervosa. The subjects in this study were 20 GP-referred female patients of normal weight who met criteria for bulimia nervosa and 16 healthy age, sex and weight matched controls. Dual energy X-ray densitometry of lumbar L1-L4 vertebrae was performed on all subjects. The patients with bulimia nervosa had a significantly lower mean lumbar bone mineral density (0.964 g/cm2) than the control group (1.043 g/cm2, p < 0.01). Within the patient group only subjects with a past history of anorexia nervosa had a significantly lower mean bone mineral density (BMD) than the controls. Small sample sizes limit the power of the study, however significant correlations were found between duration of amenorrhoea, low BMI and lumbar BMD. Bulimic patients do suffer from osteoporosis. Risk factors for this may be; a past history of anorexia nervosa, prolonged secondary amenorrhoea, and a persistently low body mass index.

Reduced bone density and major hormones regulating calcium metabolism in anorexia nervosa

Bone density of lumbar vertebrae (L2 to L4) and the whole body in 29 patients with anorexia nervosa were measured by dual photon absorptiometry, and the results were compared with those of 10 age-matched normal controls. The patients had significantly lower bone mineral density (BMD) in L3 and L2-4 than controls. However, there was no difference in whole-body BMD. L3 and L2-4 BMD was positively correlated with body weight and was negatively correlated with duration of illness and amenorrhea. Patients who had been more active 6 months before the time of the study had significantly higher L3 BMD than the less active patients. Most patients had an abnormally low serum estrogen level, whereas the mean serum levels of thyroid hormone (T3, T4), cortisol, calcitonin, parathyroid hormone and vitamin D were within the normal range. No correlation was found between L3 or L2-4 BMD and the levels of these hormones. These results suggest that severe weight loss, low physical activity, longer duration of amenorrhea and deficiency of estrogen contribute to bone loss in patients with anorexia nervosa, whereas calcium-regulating hormones such as parathyroid hormone, calcitonin and vitamin D are unlikely to be a primary contributor to bone loss.

Predictors of osteopenia in premenopausal women with anorexia nervosa

The study retrospectively evaluated risk factors for osteopenia in anorexia nervosa (AN) patients. Sixty-nine outpatient, female anorexia nervosa patients (age range 20-40 years, mean 27.5) at varying stages of recovery, and 31 controls had lumbar spine trabecular bone density assessed with single energy computed tomography (CT) scans. An investigator-based, semistructured interview assessed weight and menstrual histories from age 10. Current exercise and dietary calcium levels were categorized and lifetime durations in categories were estimated for each subject. Bone density was significantly lower in the patient group (mean 120 mg/cm3) than in the controls (mean 148 mg/cm3, P less than 0.001). Bone density correlated significantly with duration of illness, amenorrhea, and weight histories but not with measures of dietary calcium or exercise histories. The most important predictor of bone loss on stepwise multiple regression analysis was duration of AN (23% of variance, P less than 0.001), and duration of an inadequate calcium intake in adolescence explained a further 5% of the variance (P = 0.052). There was no evidence that regular exercise and adequate dietary calcium prevented bone loss related to prolonged periods of low weight and amenorrhea in these subjects.

The prevalence of eating disorders in recently admitted psychiatric in-patients

Of 107 recently admitted psychiatric patients screened for eating-disorder symptoms by questionnaire, 17% met DSM-III-R criteria for eating disorders. Eight patients (one male) had bulimia nervosa. Ten patients had eating disorder not otherwise specified: seven (three male) bulimic type, and three (one male) anorexia nervosa type. The most common concurrent diagnoses were mood and personality disorders. As eating-disorder symptoms are relevant to the diagnosis and management of other psychiatric disorders they should be assessed routinely in all psychiatric patients.