Near normalisation of lumbar spine bone density in young women with osteopenia recovered from adolescent onset anorexia nervosa: a longitudinal study

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

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

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

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

Testing the Functional Model of Bone Development: Direct and Mediating Role of Muscle Strength on Bone Properties in Growing Youth

This study examines the functional model of bone development in peri-pubertal boys and girls. Specifically, we implemented a mixed-longitudinal design and hierarchical structural models to provide experimental evidence in support of the conceptual functional model of bone development, postulating that the primary mechanical stimulus of bone strength development is muscle force. To this end, we measured radial and tibial bone properties (speed of sound, SOS), isometric grip and knee extensors strength, bone resorption (urinary NTX concentration), body mass index (BMI), somatic maturity (years from peak height velocity) and skeletal maturity (bone age) in 180 children aged 8–16 years. Measurements were repeated 2–4 times over a period of 3 years. The multilevel structural equation modeling of 406 participant-session observations revealed similar results for radial and tibial SOS. Muscle strength (i.e., grip strength for the radial and knee extension for tibial model) and NTX have a significant direct effect on bone SOS (β = 0.29 and −0.18, respectively). Somatic maturity had a direct impact on muscle strength (β = 0.24) and both a direct and indirect effect on bone SOS (total effect, β = 0.30). Physical activity and BMI also had a significant direct impact on bone properties, (β = 0.06 and −0.18, respectively), and an additional significant indirect effect through muscle strength (β = 0.01 and 0.05, respectively) with small differences per bone site and sex. Muscle strength fully mediated the impact of bone age (β = 0.14) while there was no significant effect of energy intake on either muscle strength or bone SOS. In conclusion, our results support the functional model of bone development in that muscle strength and bone metabolism directly affect bone development while the contribution of maturity, physical activity, and other modulators such as BMI, on bone development is additionally modulated through their effect on muscle strength.

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Longitudinal changes in bone parameters in young girls with anorexia nervosa

BACKGROUND

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

METHOD

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

RESULTS

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

CONCLUSION

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

Mechanical, biochemical, and dietary determinants of the functional model of bone development of the radius in children and adolescents

This study examined the degree to which various mechanical, biochemical, and dietary factors are related to nonweight bearing bone properties in 172 healthy peri-pubertal children (age, 11.7 ± 2.0 years). Dominant radial speed of sound (rSOS) was measured by transaxial quantitative ultrasound at distal radius. Potential modulating factors included somatic maturity offset (years from age of peak height velocity), grip strength, forearm lean cross-sectional area (CSA), physical activity, nutritional intake, and amino-terminal cross-linking propeptide (NTx), reflecting bone resorption. In a hierarchical regression, grip strength adjusted for CSA was the second most important predictor of rSOS after the maturity offset (β = 0.22 and β = 0.33, respectively; R² = 0.16). When relative grip strength was added to the model the contribution of sex was no longer significant. Calcium intake was a significant predictor of rSOS only after NTx was accounted for in the model (β = 0.17, R² = 0.21). This may suggest that calcium's effects on the muscle-bone unit may be modulated through bone resorption. In the final model, relative grip strength together with maturity offset, dietary calcium, and NTx explained up to 21% of the variance in rSOS in this cohort of children. Therefore, during the peri-pubertal stage, size-adjusted forearm muscle strength is related to radial bone strength after controlling for maturity, with calcium intake having a potential indirect association through NTx.

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

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

Sequences of Regressions Distinguish Nonmechanical from Mechanical Associations between Metabolic Factors, Body Composition, and Bone in Healthy Postmenopausal Women

BACKGROUND

There is increasing recognition of complex interrelations between the endocrine functions of bone and fat tissues or organs.

OBJECTIVE

The objective was to describe nonmechanical and mechanical links between metabolic factors, body composition, and bone with the use of graphical Markov models.

METHODS

Seventy postmenopausal women with a mean ± SD age of 62.3 ± 3.7 y and body mass index (in kg/m2) of 24.9 ± 3.8 were recruited. Bone outcomes were peripheral quantitative computed tomography measures of the distal and diaphyseal tibia, cross-sectional area (CSA), volumetric bone mineral density (vBMD), and cortical CSA. Biomarkers of osteoblast and adipocyte function were plasma concentrations of leptin, adiponectin, osteocalcin, undercarboxylated osteocalcin (UCOC), and phylloquinone. Body composition measurements were lean and percent fat mass, which were derived with the use of a 4-compartment model. Sequences of Regressions, a subclass of graphical Markov models, were used to describe the direct (nonmechanical) and indirect (mechanical) interrelations between metabolic factors and bone by simultaneously modeling multiple bone outcomes and their relation with biomarker outcomes with lean mass, percent fat mass, and height as intermediate explanatory variables.

RESULTS

The graphical Markov models showed both direct and indirect associations linking plasma leptin and adiponectin concentrations with CSA and vBMD. At the distal tibia, lean mass, height, and adiponectin-UCOC interaction were directly explanatory of CSA (R2 = 0.45); at the diaphysis, lean mass, percent fat mass, leptin, osteocalcin, and age-adiponectin interaction were directly explanatory of CSA (R2 = 0.49). The regression models exploring direct associations for vBMD were much weaker, with R2 = 0.15 and 0.18 at the distal and diaphyseal sites, respectively. Lean mass and UCOC were associated, and the global Markov property of the graph indicated that this association was explained by osteocalcin.

CONCLUSIONS

This study, to our knowledge, offers a novel approach to the description of the complex physiological interrelations between adiponectin, leptin, and osteocalcin and the musculoskeletal system. There may be benefits to jointly targeting both systems to improve bone health.

Imaging of the muscle-bone relationship

Muscle can be assessed by imaging techniques according to its size (as thickness, area, volume, or alternatively, as a mass) and architecture (fiber length and pennation angle), with values used as an anthropometric measure or a surrogate for force production. Similarly, the size of the bone (as area or volume) can be imaged using MRI or pQCT, although typically bone mineral mass is reported. Bone imaging measures of mineral density, size, and geometry can also be combined to calculate bone's structural strength-measures being highly predictive of bone's failure load ex vivo. Imaging of muscle-bone relationships can, hence, be accomplished through a number of approaches by adoption and comparison of these different muscle and bone parameters, dependent on the research question under investigation. These approaches have revealed evidence of direct, mechanical muscle-bone interactions independent of allometric associations. They have led to important information on bone mechanoadaptation and the influence of muscular action on bone, in addition to influences of age, gender, exercise, and disuse on muscle-bone relationships. Such analyses have also produced promising diagnostic tools for clinical use, such as identification of primary, disuse-induced, and secondary osteoporosis and estimation of bone safety factors. Standardization of muscle-bone imaging methods is required to permit more reliable comparisons between studies and differing imaging modes, and in particular to aid adoption of these methods into widespread clinical practice.

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.

Obstacles in the optimization of bone health outcomes in the female athlete triad

Maintaining low body weight for the sake of performance and aesthetic purposes is a common feature among young girls and women who exercise on a regular basis, including elite, college and high-school athletes, members of fitness centres, and recreational exercisers. High energy expenditure without adequate compensation in energy intake leads to an energy deficiency, which may ultimately affect reproductive function and bone health. The combination of low energy availability, menstrual disturbances and low bone mineral density is referred to as the 'female athlete triad'. Not all athletes seek medical assistance in response to the absence of menstruation for 3 or more months as some believe that long-term amenorrhoea is not harmful. Indeed, many women may not seek medical attention until they sustain a stress fracture. This review investigates current issues, controversies and strategies in the clinical management of bone health concerns related to the female athlete triad. Current recommendations focus on either increasing energy intake or decreasing energy expenditure, as this approach remains the most efficient strategy to prevent further bone health complications. However, convincing the athlete to increase energy availability can be extremely challenging. Oral contraceptive therapy seems to be a common strategy chosen by many physicians to address bone health issues in young women with amenorrhoea, although there is little evidence that this strategy improves bone mineral density in this population. Assessment of bone health itself is difficult due to the limitations of dual-energy X-ray absorptiometry (DXA) to estimate bone strength. Understanding how bone strength is affected by low energy availability, weight gain and resumption of menses requires further investigations using 3-dimensional bone imaging techniques in order to improve the clinical management of the female athlete triad.

Body mass, training, menses, and bone in adolescent runners: a 3-yr follow-up

Endurance runners with low bone mass during adolescence may risk attaining a low peak bone mineral density (BMD) in adulthood. Alternatively, they may mature late and undergo delayed bone mineral accumulation.

PURPOSE

The purpose of this study was to evaluate 40 adolescent runners (aged 15.9 ± 0.2 yr) at two time points, approximately 3 yr apart, to assess bone mass status and identify variables associated with bone mass change.

METHODS

Follow-up measures included a questionnaire to assess menstrual status, training, and sports participation history, height and weight, and a dual-energy x-ray absorptiometry scan to assess total body, total hip, and lumbar spine BMD, bone mineral content (BMC), BMD z-score, and body composition. We used -1 and -2 BMD z-score cutoffs to categorize runners with low bone mass.

RESULTS

Eighty-seven percent of girls with low BMD at baseline had low BMD at the follow-up. Girls with low compared with normal baseline BMD had lower follow-up adjusted total body (2220.4 ± 65.8 vs 2793.1 ± 68.2 g, P < 0.001), total hip (27.0 ± 1 vs 33.9 ± 1.0 g, P < 0.05), and lumbar spine (47.8 ± 2.0 vs 66.3 ± 2.2 g, P < 0.001) BMC values. Variables related to 3-yr training volume, menstrual function, age, developmental stage, and change in body mass explained 29%-54% of the variability in BMC change.

CONCLUSIONS

The majority of adolescent runners with low BMD at baseline had low BMD after a 3-yr follow-up. Our observations suggest that "catch-up" accrual may be difficult and, thus, emphasize the importance of gaining adequate bone mineral during the early adolescent years.

Time course of bone loss in patients with anorexia nervosa

OBJECTIVE

To evaluate the time course of bone mineral density (BMD) in women with anorexia nervosa (AN) during 2-year follow-up.

METHOD

We prospectively studied 51 female with AN aged 18-38 years, and 40 age-matched healthy women (19-34 years). BMD was measured in lumbar spine (LS), femoral neck (FN), and total hip (TH) by DXA.

RESULTS

At baseline, weight, body mass index, and lumbar and hip BMD were significantly (p < .001) lower in AN patients than in controls. Patients who gain weight showed a significant increase in BMD at FN (+1.6%; p < .05), and TH (+4.4%; p < .05) and lower nonsignificant changes in LS (+1.3%). Weight at entry, and percent change of weight were significant determinants (p < .05) of the variability in percent change of BMD at FN and TH, whereas weight at entry was the main determinant of bone modifications at lumbar spine.

DISCUSSION

Our data emphasize the influence of weight gain in recovery of bone mass in AN patients, especially at the hip.

Cross-sectional evidence of suppressed bone mineral accrual among female adolescent runners

We aimed to evaluate patterns of bone mineral accrual among a cross-sectional sample of female adolescent runners and girls participating in a nonendurance running sport. One-hundred and eighty-three interscholastic competitive female athletes (age 16.0 +/- 0.1 years), 93 endurance runners and 90 nonrunners, completed a menstrual and sports history questionnaire, had their height and weight measured, and underwent a dual-energy X-ray absorptiometry scan for the measurements of body composition and bone mass. For the majority of analyses, the girls were separated into four groups according to their age (13 to 14 years, 15 years, 16 years, and 17 to 18 years). Runners' height, weight, body mass index (BMI), percent body fat, lean tissue mass, number of menstrual cycles in the past year, and months of participation in a non-lean-build/variable-impact-loading sport were significantly lower than mean values for nonrunners. Although bone mass rose at all sites in the nonrunners between the ages of 13 to 14 years and 17 to 18 years, no such increase was noted in the runners. Runners compared with nonrunners exhibited significantly lower body weight and height-adjusted total body and lumbar spine bone mineral content (BMC) values and lower bone mineral density (BMD) Z-score values among the older (16 years and/or 17 to 18 years) but not younger (13 to 14 years and/or 15 years) age groups. These findings suggest that the runners, in contrast to the nonrunners, exhibited a suppressed bone mineral accrual pattern, which supports the notion that female adolescent endurance runners may be at risk for inadequate bone mass gains and thus a low peak BMD.

Clinical research in adolescents: challenges and opportunities using obesity as a model

Adolescent medicine is relatively young, compared to paediatric or adult medicine. Descriptive and observational studies have dominated the adolescent literature, including those studies published in the International Journal of Obesity. In addition, many studies have combined child and adolescent age groups, making it difficult to determine adolescent-specific outcomes. It is important that high quality intervention studies in adolescents occur. Adolescence is a time of extraordinary plasticity. Habits, attitudes and physical morbidity that develop during adolescence set up trajectories that have a profound influence on health and wellbeing for the long term. Overweight and obesity are an excellent example of the need for high quality intervention studies and yet in the last two decades there have been very few randomized, controlled trials of overweight and obesity management in adolescents. There are a number of complexities in adolescent research that create additional challenges to those that accompany any clinical research. These include recruitment and retention, issues around consent and confidentiality and the central role that parents play in supporting the research protocol. Pubertal stage is a potential confounder and needs to be accurately measured. This is certainly true for studies in overweight and obesity where excess adiposity influences pubertal and other hormones. The opportunities to undertake quality research in adolescents are likely to be enhanced by the use of novel approaches which acknowledge the unique features of adolescents and their world.

Factors influencing changes in bone mineral density in patients with anorexia nervosa-related osteoporosis: the effect of hormone replacement therapy

The purpose of this longitudinal study was to evaluate factors affecting changes in bone mineral density (BMD) in patients with anorexia nervosa (AN) and osteoporosis and, more particularly, to assess the benefits of hormone replacement therapy (HRT) on BMD in these patients. Our study involved 45 AN patients, 12 of whom had been treated by HRT for 2 years following a diagnosis of osteoporosis by densitometry (WHO criteria). Patients' mean age was 25.3 +/- 6.7 years. Mean duration of illness was 5.7 +/- 5.3 years. Serum calcium and phosphate were measured at baseline, as were bone remodeling markers. Osteodensitometry by dual-energy X-ray absorptiometry was performed at inclusion and after 2 years. After 2 years, no significant differences were observed between spine, femoral neck, and total hip BMDs either in the HRT group (P = 0.3, P = 0.59, P = 0.58) or in the nontreatment group (P = 0.17, P = 0.68, P = 0.98). Moreover, there were no significant differences between the two groups when changes in spine, femoral neck, and total hip BMDs at 2 years were compared (P = 0.72, P = 0.95, P = 0.58). In both groups, change in weight at 1 year correlated with change in spine BMD at 2 years (r = 0.35, P = 0.04) and change in total-hip BMD at 2 years (r = 0.35, P = 0.04) but not with change in femoral neck BMD at 2 years. Patients with a body mass index (BMI) > or = 17 kg/m(2) at 2 years showed a significant increase in total-hip BMD when compared with patients with a BMI < 17 kg/m(2) (+4.4% +/- 6.7 vs. -0.5% +/- 6.01, P = 0.03). No significant differences were observed for spine and femoral neck BMD. In patients who had recovered their menstrual cycle, significant increases were observed in spine BMD (+4% +/- 6.3 vs. -1.9% +/- 5.6, P = 0.008), femoral neck BMD (+3% +/- 6.2 vs. -2.4% +/- 8, P = 0.05), and total-hip BMD (+3% +/- 7.1 vs. -3.7% +/- 10, P = 0.04). Prevention of bone loss at 2 years in AN patients treated by HRT was not confirmed in this study. We did confirm that increase in weight at 1 year was the most predictive factor for the improvement of spine and hip BMD at 2 years.

Weight gain and restoration of menses as predictors of bone mineral density change in adolescent girls with anorexia nervosa-1

CONTEXT

Adolescents with anorexia nervosa (AN) have low bone mineral density. However, the effect of disease recovery, first, on bone density measures assessed using the Molgaard approach, which differentiates between reported low bone density resulting from short bones (based on height Z-scores) and that resulting from thin bones [based on measures of bone area (BA) for height] or light bones [based on measures of bone mineral content (BMC) for BA]; and second, on height-adjusted bone density measures, has not been well characterized. We hypothesized that menstrual recovery and weight gain (> or =10% increase in body mass index) would predict an increase in these measures of bone density.

METHODS

In a prospective observational study, lumbar and whole-body (WB) bone density was measured at 0, 6, and 12 months in 34 AN girls aged 12-18 yr and 33 controls. Using Ward's modification of the Molgaard approach, we determined measures of BMC for BA and BA for height at the lumbar spine and WB and also determined spine bone mineral apparent density and WB BMC adjusted for height.

RESULTS

Girls with AN had lower spine BMC for BA Z-scores (P = 0.0009), and lower WB BA for height Z (P < 0.0001), compared with controls. Menstrual recovery and weight gain in AN (AN-recovered) (median 9 months) resulted in a stabilization of BMD measures, whereas BMD continued to decrease in AN who did not gain weight and recover menses (AN-not recovered). AN-recovered also predicted greater increases in spine BMC for BA and WB BA for height, compared with AN-not recovered (P < 0.05).

CONCLUSIONS

Even short-term weight gain with menstrual recovery is associated with a stabilization of BMD measures.

The Female Athlete Triad

The female athlete triad (Triad) refers to the interrelationships among energy availability, menstrual function, and bone mineral density, which may have clinical manifestations including eating disorders, functional hypothalamic amenorrhea, and osteoporosis. With proper nutrition, these same relationships promote robust health. Athletes are distributed along a spectrum between health and disease, and those at the pathological end may not exhibit all these clinical conditions simultaneously. Energy availability is defined as dietary energy intake minus exercise energy expenditure. Low energy availability appears to be the factor that impairs reproductive and skeletal health in the Triad, and it may be inadvertent, intentional, or psychopathological. Most effects appear to occur below an energy availability of 30 kcal.kg(-1) of fat-free mass per day. Restrictive eating behaviors practiced by girls and women in sports or physical activities that emphasize leanness are of special concern. For prevention and early intervention, education of athletes, parents, coaches, trainers, judges, and administrators is a priority. Athletes should be assessed for the Triad at the preparticipation physical and/or annual health screening exam, and whenever an athlete presents with any of the Triad's clinical conditions. Sport administrators should also consider rule changes to discourage unhealthy weight loss practices. A multidisciplinary treatment team should include a physician or other health-care professional, a registered dietitian, and, for athletes with eating disorders, a mental health practitioner. Additional valuable team members may include a certified athletic trainer, an exercise physiologist, and the athlete's coach, parents and other family members. The first aim of treatment for any Triad component is to increase energy availability by increasing energy intake and/or reducing exercise energy expenditure. Nutrition counseling and monitoring are sufficient interventions for many athletes, but eating disorders warrant psychotherapy. Athletes with eating disorders should be required to meet established criteria to continue exercising, and their training and competition may need to be modified. No pharmacological agent adequately restores bone loss or corrects metabolic abnormalities that impair health and performance in athletes with functional hypothalamic amenorrhea.

Marked increases in bone mineral density and biochemical markers of bone turnover in patients with anorexia nervosa gaining weight

Anorexia nervosa (AN) is a life-threatening eating disorder characterized by an inability to maintain a normal body weight and amenorrhoea, often associated with osteoporosis and increased risk of fragility fractures. Bone metabolism, including markers of bone turnover (serum total alkaline phosphatase, bone alkaline phosphatase [bone AP], osteocalcin [OC] and type I collagen C-telopeptide breakdown products [sCTX]) and bone mineral density (BMD) by dual energy X-ray absorptiometry (DXA) at the spine and at the hip, were evaluated in 55 consecutive women with AN undergoing a 3-month intensive nutritional rehabilitation program. The control group was constituted of 25 healthy young medical students. In AN patients body weight increased during the 3-month nutritional program from 37.8+/-5.1 (mean+/-SD) to 51.5+/-4.5 kg. The corresponding BMI rose to values >17.5 kg/m(2) in all patients. Mean BMD significantly rose by 2.6+/-3.5% and 1.1+/-3.6% at the hip and at the spine, respectively. The markers of bone formation, serum bone AP and osteocalcin, significantly rose by two-folds, while sCTX decreased by 16%. The changes in hip BMD were positively related (p<0.005) to changes in body weight and in bone AP (p<0.02) while the changes in spine BMD were positively related to changes in serum osteocalcin (p<0.05). In the 25 patients who attended the 12-month posttreatment control, mean body weight significantly decreased by 3.6+/-6.0 kg and this was not associated with any significant change in BMD values. In the patients in whom BMI fell again below 17.5 kg/m(2) hip BMD values decreased significantly. On the contrary, in the patients who maintained BMI >17.5 kg/m(2), BMD values continued to rise up to values over the 15-month observation of 4.8+/-6.2 and 7.1+/-12.1 at the spine and hip, respectively. In conclusion, we have demonstrated that substantial gains in weight in women with chronic AN are associated with remarkable increases in BMD at both the hip and the spine. If weight is maintained, the overall improvement approach 1 SD within 1 year. The changes in both weight and BMD are correlated with improvements in bone formation markers and diminutions in a marker of bone resorption.

Determinants of skeletal loss and recovery in anorexia nervosa

CONTEXT

Anorexia nervosa (AN) is complicated by severe bone loss. The effects of persistent undernutrition and consequent neuroendocrine dysfunction on bone mass and the factors influencing skeletal recovery have not been well characterized.

OBJECTIVE

The objective of the study was to determine the rate of bone loss at the spine and hip in women with AN and whether resumption of menstrual function and/or improvement in weight are determinants of skeletal recovery in AN.

DESIGN

The study had a longitudinal design.

SETTING

The study was conducted at a clinical research center.

STUDY PARTICIPANTS

Participants included 75 ambulatory women with AN.

MAIN OUTCOME MEASURES

Bone mineral density (BMD) and body composition were measured with dual x-ray absorptiometry.

RESULTS

In women not receiving oral contraceptives, those who did not improve weight or resume menses had a mean annual rate of decline of 2.6% at the spine and 2.4% at the hip. Those who resumed menses and improved weight had a mean annual increase of 3.1% at the posteroanterior spine and 1.8% at the hip. Women who recovered menses demonstrated a mean increase of posteroanterior spine but not hip BMD, independent of weight gain. Women who improved weight, regardless of whether they recovered menstrual function, demonstrated a mean increase of hip, but not spine, BMD. Increase in fat-free mass was a more significant determinant of increased BMD than weight or fat mass gain. In women receiving oral contraceptives, there was no increase in BMD at any site despite a mean 11.7% weight increase.

CONCLUSIONS

These data suggest that rapid bone loss, at an average annual rate of about 2.5%, occurs in young women with active AN. Resumption of menstrual function is important for spine BMD recovery, whereas weight gain is critical for hip BMD recovery. We did not observe an increase in BMD with weight gain in women receiving oral contraceptives. Therefore, improvements in reproduction function and weight, with increases in lean body mass a critical component, are both necessary for skeletal recovery in women with AN.