Bone Mass Eight Years After Treatment for Adolescent-Onset Anorexia Nervosa

Prevalence and risk factors associated with low bone mineral density in Asian adolescents with anorexia nervosa and atypical anorexia nervosa

OBJECTIVE

This retrospective study aimed to evaluate the prevalence and risk factors for low bone mineral density (BMD) at diagnosis in Asian adolescent females with anorexia nervosa (AN) and atypical AN.

METHOD

We analyzed the BMD results for 213 patients between 10 and 18 years of age, with AN and atypical AN receiving care at a pediatric hospital in Singapore. We used linear regression analyses to determine if type of eating disorder, premorbid weight, and duration of amenorrhea were risk factors for low BMD. For a subset of patients with repeat BMD evaluation, we used paired t-tests to assess the impact of weight or menstrual restoration on the change in BMD.

RESULTS

The prevalence of BMD height-for-age Z-scores <-2 at presentation was higher in patients with AN (13.0%) than atypical AN (2.3%) (p = .034). In multivariate regression, a diagnosis of atypical AN was protective against low BMD at the lumbar spine (B = 0.394, p = .009) and total body less head (B = 0.774, p = .010). Duration of amenorrhea was not associated with BMD across all sites. For those with repeat BMD measures, there was significantly less deterioration in the BMD Z-scores for patients with weight or menstrual restoration (R = -0.22 ± 0.59, NR = -0.69 ± 0.43, p = .029).

CONCLUSIONS

Duration of amenorrhea was not associated with BMD in this sample. A diagnosis of AN was correlated with lower BMD than atypical AN. Further research is needed to better understand the relationship between amenorrhea, weight status, and bone health in Asian adolescents with eating disorders.

PUBLIC SIGNIFICANCE

In this sample, 13% of Asian adolescents with AN and 2.3% of Asian adolescents with atypical AN have low BMD. In our study population, duration of amenorrhea was not correlated with BMD. Among adolescents with AN, a history of being underweight at the highest pre-morbid BMI, is correlated with low BMD. It is important for physicians to take a thorough weight history in evaluating bone health in this population.

National Clinical Programme for Eating Disorders: a pragmatic review of a new national eating disorder service in Ireland

OBJECTIVE

The Health Service Executive National Clinical Programme for Eating Disorders (NCPED) launched a Model of Care for Eating Disorder Services in Ireland in 2018. Currently, one adult and two child and adolescent eating disorder services are operational out of a total of sixteen recommended. The three objectives of this paper are to describe the early (1) referral pattern, (2) level of service activity and (3) the level of service user satisfaction.

METHOD

Monthly submitted service activity data from each service to the NCPED between March 2018 and October 2020 were retrospectively analysed. One hundred and fifty-nine carers and service users completed an experience of service questionnaire (ESQ). A descriptive analysis of referral pattern, level of service activity and ESQ was performed. A thematic analysis was performed on three qualitative questions on the ESQ.

RESULTS

There was substantial referral numbers to eating disorder services by 18 months (n = 258). The main referral source was community mental health teams. The majority (n = 222, 86%) of referrals were offered an assessment. The most common age profile was 10-17 years of age (n = 120, 54.1%), and anorexia nervosa was the most common disorder (n = 96, 43.2%). ESQ results demonstrate that most service users were satisfied with their service, and the main themes were carer involvement, staff expertise, therapeutic alliance and service access.

CONCLUSIONS

This preliminary service activity and service user satisfaction data highlight several issues, including trends when setting up a regional eating disorder service, potential pitfalls of pragmatic data collection and the need for adequate information-technology infrastructure.

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.

Anorexia Nervosa and Osteoporosis: Pathophysiology and Treatment

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

Bone Mineral Density after Weight Gain in 160 Patients with Anorexia Nervosa

Low bone mineral density (BMD) is a frequent complication in anorexia nervosa (AN). There are controversial points of views regarding the restoration of bone mineralization after recovery in AN. We aimed to assess changes of BMD at 3 years in patients with AN and to explore the relationships between body composition, physical activity, and BMD. Patients with AN were included from 2009 to 2011 in a first visit (T0) with evaluation of weight, height, body mass index (BMI), body composition [fat mass (FM) and fat-free mass], and BMD. Those who had low BMD, either osteoporosis or osteopenia, were admitted in a second visit (T1) to carry out a new bone densitometry examination and body composition; they were also asked for their physical activity. At T0, our study involved 160 patients. Low BMD was observed in 53.6% of them and significant factors associated with demineralization were lower BMIs (16.5 ± 2.1 vs 17.3 ± 2.3 kg/m², p = 0.01) and higher duration of AN (11.4 ± 10.5 vs 6.4 ± 6.5 years, p = 0.001). At 3 years follow-up (T1), 42 patients were involved and no significant changes in BMD were observed despite body weight increase (3.8 ± 6.1 kg). Interestingly, FM gain was a significant factor associated with BMD improvement at follow-up (8.0 ± 9.1 vs 3.0 ± 3.5 kg, p = 0.02). Our findings suggest that the restoration of normal bone values is not related to the increase of body weight, at least after 3 years. FM seems to play an important role in the pathophysiological mechanism of osteoporosis and osteopenia in AN.

Underweight, overweight, and pediatric bone fragility: impact and management

Skeletal health is modulated by a variety of factors, including genetic makeup, hormonal axes, and environment. Across all ages, extremes of body weight may exert a deleterious effect on bone accretion and increase fracture risk. The incidence of both anorexia nervosa and obesity, each involving extreme alterations in body composition, is rising among youth, and secondary osteoporosis is increasingly being diagnosed among affected children and adolescents. Compared with the elderly, the definition of osteoporosis that stems from any underlying condition differs for the pediatric population and special precautions are required with regard to treatment of young patients. Early recognition and management of both underweight and overweight youth and the accompanying consequences on bone and mineral metabolism are essential for preservation of skeletal health, although prevention of bone loss and optimization of bone mineral accrual remain the most important protective measures.

Bone health in eating disorders

Eating disorders (EDs) put adolescents and young adults at risk for impaired bone health. Low bone mineral density (BMD) with ED is caused by failure to accrue peak bone mass in adolescence and bone loss in young adulthood. Although ED patients diagnosed with bone loss may be asymptomatic, some suffer bone pains and have increased incidence of fractures. Adolescents with ED are prone to increased prevalence of stress fractures, kyphoscoliosis and height loss. The clinical picture of the various EDs involves endocrinopathies that contribute to impaired bone health. Anorexia nervosa (AN) is characterized by low bone turnover, with relatively higher osteoclastic (bone resorptive) than osteoblastic (bone formation) activity. Bone loss in AN occurs in both the trabecular and cortical bones, although the former is more vulnerable. Bone loss in AN has been shown to be influenced by malnutrition and low weight, reduced fat mass, oestrogen and androgen deficiency, glucocorticoid excess, impaired growth hormone-insulin-like growth factor 1 axis, and more. Bone loss in AN may not be completely reversible despite recovery from the illness. Treatment modalities involving hormonal therapies have limited effectiveness, whereas increased caloric intake, weight gain and resumption of menses are essential to improved BMD.

Bone disease in anorexia nervosa

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

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

OBJECTIVE

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

SUBJECTS AND METHODS

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

RESULTS

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

CONCLUSION

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