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

Associations between bone mineral density, body composition and amenorrhoea in females with eating disorders: a systematic review and meta-analysis

BACKGROUND

Lower bone mineral density (BMD) increases the risk of osteoporosis in individuals with eating disorders (EDs), particularly women with anorexia nervosa (AN), making them susceptible to pain and fractures throughout adulthood. In AN, low weight, hypothalamic amenorrhoea, and longer illness duration are established risk factors for low BMD, and in people with other EDs a history of AN seems to be an important risk factor for low BMD.

PURPOSE

To conduct a systematic review and meta-analysis of BMD in individuals with EDs, including AN, bulimia nervosa (BN), binge-eating disorder (BED) and other specified feeding or eating disorders (OSFED) compared to healthy controls (HC).

METHODS

Following PRISMA guidelines, electronic databases were reviewed and supplemented with a literature search until 2/2022 of publications measuring BMD (dual-energy X-ray absorptiometry or dual photon absorptiometry) in females with any current ED diagnosis and a HC group. Primary outcomes were spine, hip, femur and total body BMD. Explanatory variables were fat mass, lean mass and ED clinical characteristics (age, illness duration, body mass index (BMI), amenorrhoea occurrence and duration, and oral contraceptives use).

RESULTS

Forty-three studies were identified (N = 4163 women, mean age 23.4 years, min: 14.0, max: 37.4). No study with individuals with BED met the inclusion criteria. BMD in individuals with AN (total body, spine, hip, and femur), with BN (total body and spine) and with OSFED (spine) was lower than in HC. Meta-regression analyses of women with any ED (AN, BN or OSFED) (N = 2058) showed low BMI, low fat mass, low lean mass and being amenorrhoeic significantly associated with lower total body and spine BMD. In AN, only low fat mass was significantly associated with low total body BMD.

CONCLUSION

Predictors of low BMD were low BMI, low fat mass, low lean mass and amenorrhoea, but not age or illness duration. In people with EDs, body composition measurement and menstrual status, in addition to BMI, are likely to provide a more accurate assessment of individual risk to low BMD and osteoporosis.

Aging of Skeletal Stem Cells

The skeletal system is generated and maintained by its progenitors, skeletal stem cells (SSCs), across the duration of life. Gradual changes associated with aging result in significant differences in functionality of SSCs. Declines in bone and cartilage production, increase of bone marrow adipose tissue, compositional changes of cellular microenvironments, and subsequent deterioration of external and internal structures culminate in the aged and weakened skeleton. The features and mechanisms of skeletal aging, and of its stem and progenitor cells in particular, are topics of recent investigation. The discovery of functionally homogeneous SSC populations with a defined cell surface phenotype has allowed for closer inspection of aging in terms of its effects on transcriptional regulation, cell function, and identity. Here, we review the aspects of SSC aging on both micro- and macroscopic levels. Up-to-date knowledge of SSC biology and aging is presented, and directions for future research and potential therapies are discussed. The realm of SSC-mediated bone aging remains an important component of global health and a necessary facet in our understanding of human aging.

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.

Estrogen for the Treatment of Low Bone Mineral Density in Anorexia Nervosa

Anorexia nervosa is a disorder of chronic, self-induced negative energy balance which typically results in a low body weight. Functional hypothalamic amenorrhea is an adaptive response to states of negative energy balance and chronic undernutrition. A majority of women with anorexia nervosa are amenorrheic with resultant hypoestrogenemia, and longer durations of amenorrhea are associated with lower bone mineral density in this population. In this review, we highlight studies that have investigated the effects of estrogen replacement on bone mineral density in anorexia nervosa, including prospective and randomized studies that show no benefit to treatment with oral estrogen with respect to bone mineral density in either adolescent girls or women with anorexia nervosa. We also review data from a randomized, placebo-controlled study in adolescent girls and a prospective, open-label pilot study in women with anorexia nervosa suggesting that transdermal estrogen may have beneficial effects with respect to bone mineral density in this population.

Body composition in anorexia nervosa: Meta-analysis and meta-regression of cross-sectional and longitudinal studies

OBJECTIVE

Clinically, anorexia nervosa (AN) presents with altered body composition. We quantified these alterations and evaluated their relationships with metabolites and hormones in patients with AN longitudinally.

METHOD

In accordance with PRISMA guidelines, we conducted 94 meta-analyses on 62 samples published during 1996-2019, comparing up to 2,319 pretreatment, posttreatment, and weight-recovered female patients with AN with up to 1,879 controls. Primary outcomes were fat mass, fat-free mass, body fat percentage, and their regional distribution. Secondary outcomes were bone mineral density, metabolites, and hormones. Meta-regressions examined relationships among those measures and moderators.

RESULTS

Pretreatment female patients with AN evidenced 50% lower fat mass (mean difference [MD]: -8.80 kg, 95% CI: -9.81, -7.79, Q = 1.01 × 10-63 ) and 4.98 kg (95% CI: -5.85, -4.12, Q = 1.99 × 10-28 ) lower fat-free mass, with fat mass preferentially stored in the trunk region during early weight restoration (4.2%, 95% CI: -2.1, -6.2, Q = 2.30 × 10-4 ). While the majority of traits returned to levels seen in healthy controls after weight restoration, fat-free mass (MD: -1.27 kg, 95% CI: -1.79, -0.75, Q = 5.49 × 10-6 ) and bone mineral density (MD: -0.10 kg, 95% CI: -0.18, -0.03, Q = 0.01) remained significantly altered.

DISCUSSION

Body composition is markedly altered in AN, warranting research into these phenotypes as clinical risk or relapse predictors. Notably, the long-term altered levels of fat-free mass and bone mineral density suggest that these parameters should be investigated as potential AN trait markers.

RESUMENOBJETIVO

Clínicamente, la anorexia nervosa (AN) se presenta con alteraciones en la composición corporal. Cuantificamos estas alteraciones y evaluamos longitudinalmente su relación con metabolitos y hormonas en pacientes con AN. MÉTODO: De acuerdo con las pautas PRISMA, realizamos 94 meta-análisis en 62 muestras publicadas entre 1996-2019, comparando hasta 2,319 pacientes mujeres en pre-tratamiento, post-tratamiento, y recuperadas en base al peso con hasta 1,879 controles. Las principales medidas fueron masa grasa, masa libre de grasa, porcentaje de grasa corporal y su distribución regional. Las medidas secundarias fueron densidad mineral ósea, metabolitos y hormonas. Las meta-regresiones examinaron las relaciones entre esas medidas y moderadores.

RESULTADOS

Las pacientes femeninas con AN pre-tratamiento mostraron un 50% menos de masa grasa (MD: -8.80 kg, CI 95%: -9.81, -7.79, Q = 1.01 × 10-63 ) y 4.98 kg (CI 95%: -5.85, -4.12, Q = 1.99 × 10-28 ) menos de masa libre de grasa, con masa grasa preferentemente almacenada en la región del tronco durante la recuperación temprana del peso (4.2%, CI 95%: -2.1, -6.2, Q = 2.30 × 10-4 ). Aunque la mayoría de los rasgos regresaron a los niveles vistos en los controles sanos después de la restauración del peso, la masa libre de grasa (MD: -1.27 kg, CI 95%: -1.79, -0.75, Q = 5.49 × 10-6 ) y la densidad mineral ósea (MD: -0.10 kg, CI 95%: -0.18, -0.03, Q = 0.01) permanecieron significativamente alteradas. DISCUSIÓN: La composición corporal es marcadamente alterada en la AN, lo que garantiza la investigación en estos fenotipos como predictores de riesgo clínico o de recaída. Notablemente, la alteración a largo plazo de los niveles de masa libre de grasa y densidad mineral ósea sugieren que estos parámetros debe ser investigados como potenciales rasgos indicadores de 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.

Oral contraceptives partially protect from bone loss in young women with anorexia nervosa

OBJECTIVE

To evaluate the potentially protective effects of oral contraceptives (OC) on bone loss in a large population of young women with anorexia nervosa (AN).

DESIGN

Cross-sectional study.

SETTING

University hospital.

PATIENT(S)

Three hundred and five patients with AN (99 of them using OC) and 121 age-matched controls.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Areal bone mineral density (aBMD) evaluated by dual-energy X-ray absorptiometry and bone turnover markers, with leptin evaluated concomitantly.

RESULT(S)

Although the AN patients taking OC presented lower aBMD compared with the controls at all bone sites, the whole body excepted, their aBMD values were systematically higher than those of AN patients who were not taking OC for the whole body and the lumbar spine, femoral neck, hip, and radius. These differences persisted after multiple adjustments. Preservation of aBMD improved with longer durations of OC use and shorter delays between disease onset and the start of OC. Moreover, patients with the lowest body mass index showed the best bone tissue responses to OC. Bone formation markers were systematically lower in the two groups of patients with AN compared with the controls. The markers of bone resorption were normalized in AN patients using OC.

CONCLUSION(S)

Although OC use does not provide total protection of aBMD, our data suggest that OC might be prescribed for young women with AN to limit their bone loss.

Association of Insulin Resistance with Lower Bone Volume and Strength Index of the Proximal Femur in Nondiabetic Postmenopausal Women

Background

Type 2 diabetes mellitus is associated with an increased risk of osteoporotic fracture despite relatively preserved bone mineral density (BMD). Although this paradox might be attributed to the influence of insulin resistance (IR) on bone structure and material properties, the association of IR with femur bone geometry and strength indices remains unclear.

Methods

Using data from the Cardiovascular and Metabolic Disease Etiology Research Center cohort study, we conducted a cross-sectional analysis among nondiabetic postmenopausal women. IR was estimated using the homeostasis model assessment of IR (HOMA-IR). Compartment-specific volumetric BMD (vBMD) and bone volume of proximal femur were measured using quantitative computed tomography. The compressive strength index (CSI), section modulus (Z), and buckling ratio of the femoral neck were calculated as bone strength indices.

Results

Among 1,008 subjects (mean age, 57.3 years; body mass index [BMI], 23.6 kg/m²), BMI, waist circumference, and vBMD of the femoral neck and total hip increased in a linear trend from the lowest (<1.37) to highest (≥2.27) HOMA-IR quartile (P<0.05 for all). The HOMA-IR showed an independent negative association with total bone volume (standardized β=−0.12), cortical volume (β=−0.05), CSI (β=−0.013), and Z (β=−0.017; P<0.05 for all) of the femoral neck after adjustment for age, weight, height, physical activity, and vitamin D and high-sensitivity C-reactive protein levels. However, the association between HOMA-IR and vBMD was attenuated in the adjusted model (femoral neck, β=0.94; P=0.548).

Conclusions

Elevated HOMA-IR was associated with lower cortical bone volume and bone strength indices in nondiabetic postmenopausal women, independent of age and body size.

Pharmacological treatment options for low Bone Mineral Density and secondary osteoporosis in Anorexia Nervosa: A systematic review of the literature

OBJECTIVE

Although there are several evidence-based treatments available to increase Bone Mineral Density (BMD) and reduce fracture risk in aging men and women, there are still uncertainties regarding which treatments are efficacious in reducing lifetime fracture risk in women with Anorexia Nervosa (AN).

METHODS

Medline, PsychInfo, Embase and the Cochrane Database were searched for English Language Studies. Inclusion criteria were studies of females of any age with AN who received pharmacological treatment with the primary aim to increase BMD or reduce fracture risk. Data were extracted from each study regarding pharmacological treatment and dosage used, BMD and bone formation marker outcomes; and participant characteristics including age, Body Mass Index (BMI), duration of AN, and duration of amenorrhea.

RESULTS

675 studies were reviewed, of which 19 fit the inclusion criteria and were included in the final review, investigating a total of 1119 participants; 10 of the 19 included studies were double-blind RCTs. The remaining studies consisted of prospective observational studies, a retrospective cohort study, a case-control study and five non-randomised control trials. Bisphosphonates were effective in increasing BMD in adult women with AN, while estrogen administered transdermally resulted in significant increases in BMD in mature adolescents with AN. Administration of oral contraceptives (OC) did not significantly increase BMD in randomised or controlled trials, however, lifetime OC use was associated with higher spinal BMD.

CONCLUSION

Future research should clarify the safety of long-term bisphosphonate use in adult women with AN, and verify that transdermal estrogen replacement increases BMD in women with AN.

A systematic review and meta-analysis of the association between eating disorders and bone density

This meta-analysis investigates the effect of an eating disorder on bone mineral density in two eating disorder subtypes. Following conflicting findings in previous literature, this study finds that not only anorexia nervosa, but also bulimia nervosa has a detrimental effect on BMD. Key predictors of this relationship are discussed. This systematic review and meta-analysis investigates bone mineral density (BMD) in individuals with anorexia nervosa (AN) and bulimia nervosa (BN) in comparison to healthy controls (HCs). AN has been associated with low BMD and a risk of fractures and mixed results have been obtained for the relationship between BN and BMD. Deciphering the effect these two ED subtypes on BMD will determine the effect of low body weight (a characteristic of AN) versus the effects of periods of restrictive eating and malnutrition which are common to both AN and BN. We conducted a systematic search through the electronic databases MedLine, EMBASE and PsychInfo and the Cochrane Library to investigate and quantify this relationship. We screened 544 articles and included 27 studies in a random-effect meta-analysis and calculated the standardised mean difference (SMD) in BMD between women with a current diagnosis of AN (n = 785) vs HCs (n = 979) and a current diagnosis of BN (n = 187) vs HCs (n = 350). The outcome measures investigated were spinal, hip, femoral neck and whole body BMD measured by DXA or DPA scanning. A meta-regression investigated the effect of factors including age, duration since diagnosis, duration of amenorrhea and BMI on BMD. The mean BMI of participants was 16.65 kg/m(2) (AN), 21.16 kg/m(2) (BN) and 22.06 kg/m(2) (HC). Spine BMD was lowest in AN subjects (SMD, -3.681; 95 % CI, -4.738, -2.625; p < 0.0001), but also lower in BN subjects compared with HCs (SMD, -0.472; 95 % CI, -0.688, -0.255; p < 0.0001). Hip, whole body and femoral neck BMD were reduced to a statistically significant level in AN but not BN groups. The meta-regression was limited by the number of included studies and did not find any significant predictors. This meta-analysis confirms the association between low BMD and AN and presents a strong argument for assessing BMD not only in patients with AN, but also in patients with BN.

Preterm Children Born Small for Gestational Age are at Risk for Low Adult Bone Mass

Cross-sectional studies suggest that premature birth and low birth weight may both be associated with low peak bone mass. We followed bone traits in preterm individuals and controls for 27 years and examined the effects of birth weight relative to gestational age [stratified as small for gestational age (SGA) or appropriate for gestational (AGA)] on adult bone mineral density (BMD). We measured distal forearm BMC (g/cm) and BMD (g/cm(2)) with single-photon absorptiometry (SPA) in 46 preterm children (31 AGA and 15 SGA) at mean age 10.1 years (range 4-16) and in 84 healthy age-matched children. The measurements were repeated 27 years later with the same SPA apparatus but then also with dual energy absorptiometry and peripheral computed tomography (pQCT). Preterm individuals were shorter (p = 0.03) in adulthood than controls. Preterm AGA individuals had similar BMC and BMD height-adjusted Z-scores in adulthood compared to controls. Preterm SGA individuals had lower distal forearm BMC and BMD height-adjusted Z-scores in adulthood than both controls and preterm AGA individuals. Preterm SGA individuals had lower gain from childhood to adulthood in distal forearm BMC height-adjusted Z-scores than controls (p = 0.03). The deficits in preterm SGA individuals in adulthood were also captured by DEXA in height-adjusted femoral neck (FN) BMC Z-score and height-adjusted FN BMD Z-score and by pQCT in tibial cross-sectional area (CSA) Z-score and stress strain index (SSI) Z-score, where all measurements were lower than controls (all p values <0.05). Preterm SGA individuals are at increased risk of reaching low adult bone mass, at least partly due to a deficit in the accrual of bone mineral during growth. In our cohort, we were unable to find a similar risk in preterm AGA individuals.

A Pediatric Bone Mass Scan has Poor Ability to Predict Peak Bone Mass: An 11-Year Prospective Study in 121 Children

This 11-year prospective longitudinal study examined how a pre-pubertal pediatric bone mass scan predicts peak bone mass. We measured bone mineral content (BMC; g), bone mineral density (BMD; g/cm(2)), and bone area (cm(2)) in femoral neck, total body and lumbar spine by dual-energy X-ray absorptiometry in a population-based cohort including 65 boys and 56 girls. At baseline all participants were pre-pubertal with a mean age of 8 years (range 6-9), they were re-measured at a mean 11 years (range 10-12) later. The participants were then mean 19 years (range 18-19), an age range that corresponds to peak bone mass in femoral neck in our population. We calculated individual BMC, BMD, and bone size Z scores, using all participants at each measurement as reference and evaluated correlations between the two measurements. Individual Z scores were also stratified in quartiles to register movements between quartiles from pre-pubertal age to peak bone mass. The correlation coefficients (r) between pre-pubertal and young adulthood measurements for femoral neck BMC, BMD, and bone area varied between 0.37 and 0.65. The reached BMC value at age 8 years explained 42 % of the variance in the BMC peak value; the corresponding values for BMD were 31 % and bone area 14 %. Among the participants with femoral neck BMD in the lowest childhood quartile, 52 % had left this quartile at peak bone mass. A pediatric bone scan with a femoral neck BMD value in the lowest quartile had a sensitivity of 47 % [95 % confidence interval (CI) 28, 66] and a specificity of 82 % (95 % CI 72, 89) to identify individuals who would remain in the lowest quartile at peak bone mass. The pre-pubertal femoral neck BMD explained only 31 % of the variance in femoral neck peak bone mass. A pre-pubertal BMD scan in a population-based sample has poor ability to predict individuals who are at risk of low peak bone mass.

Current perspectives on the etiology and manifestation of the "silent" component of the Female Athlete Triad

The Female Athlete Triad (Triad) represents a syndrome of three interrelated conditions that originate from chronically inadequate energy intake to compensate for energy expenditure; this environment results in insufficient stored energy to maintain physiological processes, a condition known as low energy availability. The physiological adaptations associated with low energy availability, in turn, contribute to menstrual cycle disturbances. The downstream effects of both low energy availability and suppressed estrogen concentrations synergistically impair bone health, leading to low bone mineral density, compromised bone structure and microarchitecture, and ultimately, a decrease in bone strength. Unlike the other components of the Triad, poor bone health often does not have overt symptoms, and therefore develops silently, unbeknownst to the athlete. Compromised bone health among female athletes increases the risk of fracture throughout the lifespan, highlighting the long-term health consequences of the Triad. The purpose of this review is to examine the current state of Triad research related to the third component of the Triad, ie, poor bone health, in an effort to summarize what we know, what we are learning, and what remains unknown.

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.

A pediatric bone mass scan has poor ability to predict adult bone mass: a 28-year prospective study in 214 children

As the correlation of bone mass from childhood to adulthood is unclear, we conducted a long-term prospective observational study to determine if a pediatric bone mass scan could predict adult bone mass. We measured cortical bone mineral content (BMC [g]), bone mineral density (BMD [g/cm(2)]), and bone width (cm) in the distal forearm by single photon absorptiometry in 120 boys and 94 girls with a mean age of 10 years (range 3-17) and mean 28 years (range 25-29) later. We calculated individual and age-specific bone mass Z scores, using the control cohort included at baseline as reference, and evaluated correlations between the two measurements with Pearson's correlation coefficient. Individual Z scores were also stratified in quartiles to register movements between quartiles from growth to adulthood. BMD Z scores in childhood and adulthood correlated in both boys (r = 0.35, p < 0.0001) and girls (r = 0.50, p < 0.0001) and in both children ≥10 years at baseline (boys r = 0.43 and girls r = 0.58, both p < 0.0001) and children <10 years at baseline (boys r = 0.26 and girls r = 0.40, both p < 0.05). Of the children in the lowest quartile of BMD, 58% had left the lowest quartile in adulthood. A pediatric bone scan with a value in the lowest quartile had a sensitivity of 48% (95% confidence interval [CI] 27-69%) and a specificity of 76% (95% CI 66-84%) to identify individuals who would remain in the lowest quartile also in adulthood. Childhood forearm BMD explained 12% of the variance in adult BMD in men and 25% in women. A pediatric distal forearm BMD scan has poor ability to predict adult bone mass.

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.

Body composition and reproductive function exert unique influences on indices of bone health in exercising women

Reproductive function, metabolic hormones, and lean mass have been observed to influence bone metabolism and bone mass. It is unclear, however, if reproductive, metabolic and body composition factors play unique roles in the clinical measures of areal bone mineral density (aBMD) and bone geometry in exercising women. This study compares lumbar spine bone mineral apparent density (BMAD) and estimates of femoral neck cross-sectional moment of inertia (CSMI) and cross-sectional area (CSA) between exercising ovulatory (Ov) and amenorrheic (Amen) women. It also explores the respective roles of reproductive function, metabolic status, and body composition on aBMD, lumbar spine BMAD and femoral neck CSMI and CSA, which are surrogate measures of bone strength. Among exercising women aged 18-30 years, body composition, aBMD, and estimates of femoral neck CSMI and CSA were assessed by dual-energy x-ray absorptiometry. Lumbar spine BMAD was calculated from bone mineral content and area. Estrone-1-glucuronide (E1G) and pregnanediol glucuronide were measured in daily urine samples collected for one cycle or monitoring period. Fasting blood samples were collected for measurement of leptin and total triiodothyronine. Ov (n = 37) and Amen (n = 45) women aged 22.3 ± 0.5 years did not differ in body mass, body mass index, and lean mass; however, Ov women had significantly higher percent body fat than Amen women. Lumbar spine aBMD and BMAD were significantly lower in Amen women compared to Ov women (p < 0.001); however, femoral neck CSA and CSMI were not different between groups. E1G cycle mean and age of menarche were the strongest predictors of lumbar spine aBMD and BMAD, together explaining 25.5% and 22.7% of the variance, respectively. Lean mass was the strongest predictor of total hip and femoral neck aBMD as well as femoral neck CSMI and CSA, explaining 8.5-34.8% of the variance. Upon consideration of several potential osteogenic stimuli, reproductive function appears to play a key role in bone mass at a site composed of primarily trabecular bone. However, lean mass is one of the most influential predictors of bone mass and bone geometry at weight-bearing sites, such as the hip.

Bone mineral density in girls with functional hypothalamic amenorrhea subjected to estroprogestagen treatment--a 4-year prospective study

The aim of this study was to evaluate the effects of 4-year estroprogestagen therapy (EP) on the bone mineral density (BMD) of 16- to 17-year-old girls with functional hypothalamic amenorrhea (FHA, n = 78). Baseline values of hormonal parameters, bone fraction of alkaline phosphatase (BALP), and cross-linked n-telopeptide of type I collagen (Ntx) were taken along with BMD measurements. Follow-up measurements of laboratory parameters were performed after 6 months of EP treatment. BMD was measured on a yearly basis. Six-month treatment resulted in a marked increase in estradiol levels and a significant decrease in BALP and Ntx. The relative increase in BMD was highest after the second year of treatment. Based on the dynamics of BMD changes during the first year of treatment, we identified a subgroup with no or insignificant reactions to the treatment. It was characterized by significantly higher baseline BMD and markedly lower baseline Ntx compared to the patients who responded to 1-year therapy well or extremely well. Further follow-up proved, however, that this subgroup did not differ significantly in terms of the long-term prognosis for BMD normalization. In conclusion, this study showed that EP therapy is effective in the treatment of BMD disorders associated with FHA.

Thin healthy women have a similar low bone mass to women with anorexia nervosa

An association between anorexia nerviosa (AN) and low bone mass has been demonstrated. Bone loss associated with AN involves hormonal and nutritional impairments, though their exact contribution is not clearly established. We compared bone mass in AN patients with women of similar weight with no criteria for AN, and a third group of healthy, normal-weight, age-matched women. The study included forty-eight patients with AN, twenty-two healthy eumenorrhoeic women with low weight (LW group; BMI < 18·5 kg/m2) and twenty healthy women with BMI >18·5 kg/m2 (control group), all of similar age. We measured lean body mass, percentage fat mass, total bone mineral content (BMC) and bone mineral density in lumbar spine (BMD LS) and in total (tBMD). We measured anthropometric parameters, leptin and growth hormone. The control group had greater tBMD and BMD LS than the other groups, with no differences between the AN and LW groups. No differences were found in tBMD, BMD LS and total BMC between the restrictive (n 25) and binge–purge type (n 23) in AN patients. In AN, minimum weight (P = 0·002) and percentage fat mass (P = 0·02) explained BMD LS variation (r2 0·48) and minimum weight (r2 0·42; P = 0·002) for tBMD in stepwise regression analyses. In the LW group, BMI explained BMD LS (r2 0·72; P = 0·01) and tBMD (r2 0·57; P = 0·04). We concluded that patients with AN had similar BMD to healthy thin women. Anthropometric parameters could contribute more significantly than oestrogen deficiency in the achievement of peak bone mass in AN patients.

The endocrinopathies of anorexia nervosa

OBJECTIVE

To describe the hormonal adaptations and alterations in anorexia nervosa.

METHODS

We performed a PubMed search of the English-language literature related to the pathophysiology of the endocrine disorders observed in anorexia nervosa, and we describe a case to illustrate these findings.

RESULTS

Anorexia nervosa is a devastating disease with a variety of endocrine manifestations. The effects of starvation are extensive and negatively affect the pituitary gland, thyroid gland, adrenal glands, gonads, and bones. Appetite is modulated by the neuroendocrine system, and characteristic patterns of leptin and ghrelin concentrations have been observed in anorexia nervosa. A thorough understanding of refeeding syndrome is imperative to nutrition rehabilitation in these patients to avoid devastating consequences. Although most endocrinopathies associated with anorexia nervosa reverse with recovery, short stature, osteoporosis, and infertility may be long-lasting complications. We describe a 20-year-old woman who presented with end-stage anorexia nervosa whose clinical course reflects the numerous complications caused by this disease.

CONCLUSIONS

The effects of severe malnutrition and subsequent refeeding are extensive in anorexia nervosa. Nutrition rehabilitation is the most appropriate treatment for these patients; however, it must be done cautiously.

Strategies to reverse bone loss in women with functional hypothalamic amenorrhea: a systematic review of the literature

Functional hypothalamic amenorrhea (FHA) impairs the attainment of peak bone mass and as such can increase the risk of fractures later in life. To document available treatment strategies, we conducted a systematic review of the literature. We report that hormonal therapies have limited effectiveness in increasing bone mass, whereas increased caloric intake resulting in weight gain and/or resumption of menses is an essential strategy for restoring bone mass in women with FHA.

INTRODUCTION

Women with functional hypothalamic amenorrhea (FHA) may not achieve peak bone mass (PBM), which increases the risk of stress fractures, and may increase the risk of osteoporotic fractures in later life.

METHODS

To identify effective treatment strategies for women with FHA, we conducted a systematic review of the literature. We included randomized controlled trials (RCTs), cross-sectional studies, and case studies that reported on the effects of pharmacological and non-pharmacological interventions on bone mineral density (BMD) or bone turnover in women with FHA.

RESULTS

Most published studies (n=26) were designed to treat the hormonal abnormalities observed in women with FHA (such as low estrogen, leptin, insulin-like growth factor-1, and DHEA); however none of these treatments demonstrated consistent improvements in BMD. Therapies containing an estrogen given for 8-24 months resulted in variable improvements (1.0-19.0%) in BMD, but failed to restore bone mass to that of age-matched controls. Three studies reported on the use of bisphosphonates (3-12 months) in anorexic women, which appear to have limited effectiveness to improve BMD compared to nutritional treatments. Another three investigations showed no improvements in BMD after androgen therapy (DHEA and testosterone) in anorexic women. In contrast, reports (n=9) describing an increase in caloric intake that results in weight gain and/or the resumption of menses reported a 1.1-16.9% increase in BMD concomitant with an improvement in bone formation and reduction in bone resorption markers.

CONCLUSIONS

Our literature review indicates that the most successful, and indeed essential strategy for improving BMD in women with FHA is to increase caloric intake such that body mass is increased and there is a resumption of menses. Further long-term studies to determine the persistence of this effect and to determine the effects of this and other strategies on fracture risk are needed.

Effect of oral contraceptives and hormone replacement therapy on bone mineral density in premenopausal and perimenopausal women: a systematic review

Seventy five articles on the effect of oral contraceptives and other hormone replacement on bone density in premenopausal and perimenopausal women were reviewed. The evidence was appraised using the Oxford Centre for Evidence-Based Medicine levels of evidence. There is good evidence for a positive effect of oral contraceptives on bone density in perimenopausal women, and fair evidence for a positive effect in "hypothalamic" oligo/amenorrhoeic premenopausal women. There is limited evidence for a positive effect in healthy and anorexic premenopausal women. In hypothalamic oligo/amenorrhoeic women, baseline bone density has been shown to be significantly lower than that in healthy controls, therefore the decision to treat is clinically more important. The ideal formulation(s) and duration of treatment remain to be determined by further longitudinal and prospective randomised controlled trials in larger subject populations.

Metabolic Bone Disease in Children

Metabolic bone disease in children includes many hereditary and acquired conditions of diverse etiology that lead to disturbed metabolism of the bone tissue. Some of these processes primarily affect bone; others are secondary to nutritional deficiencies, a variety of chronic disorders, and/or treatment with some drugs. Some of these disorders are rare, but some present public health concerns (for instance, rickets) that have been well known for many years but still persist. The most important clinical consequences of bone metabolic diseases in the pediatric population include reduced linear growth, bone deformations, and non-traumatic fractures leading to bone pain, deterioration of motor development and disability. In this article, we analyze primary and secondary osteoporosis, rickets, osteomalacia (nutritional and hereditary vitamin D-dependent, hypophosphatemic and that due to renal tubular abnormalities), renal osteodystrophy, sclerosing bony disorders, and some genetic bone diseases (hypophosphatasia, fibrous dysplasia, skeletal dysplasia, juvenile Paget disease, familial expansile osteolysis, and osteoporosis pseudoglioma syndrome). Early identification and treatment of potential risk factors is essential for skeletal health in adulthood. In most conditions it is necessary to ensure an appropriate diet, with calcium and vitamin D, and an adequate amount of physical activity as a means of prevention. In secondary bone diseases, treatment of the primary disorder is crucial. Most genetic disorders await prospective gene therapies, while bone marrow transplantation has been attempted in other disorders. At present, affected patients are treated symptomatically, frequently by interdisciplinary teams. The role of exercise and pharmacologic therapy with calcium, vitamin D, phosphate, bisphosphonates, calcitonin, sex hormones, growth hormone, and thiazides is discussed. The perspectives on future therapy with insulin-like growth factor-1, new analogs of vitamin D, strontium, osteoprotegerin, and calcimimetics are presented.

Diet and exercise during growth have site-specific skeletal effects: a co-twin control study

Exercise and improved nutrition offer safe, low-cost and widely applicable approaches to potentially reduce the burden of fractures. We conducted a cross-sectional study of 30 monozygotic and 26 dizygotic male twin pairs, aged 7-20 years to test the following hypotheses: (1) Associations between bone mass and dimensions and exercise are greater than between bone mass and dimensions and protein or calcium intakes; (2) exercise or nutrient intake are associated with appendicular bone mass before puberty and axial bone mass during and after puberty. Total body and posteroanterior (PA) lumbar spine bone mineral content (BMC) and mid-femoral shaft dimensions were measured using dual energy X-ray absorptometry (DEXA). Relationships between within-pair differences in nutrient intake (determined by weighed-food diaries) or exercise duration (determined by questionnaire) and within-pair differences in BMC and bone dimensions were tested using linear regression analysis. In multivariate analyses, within-pair differences in exercise duration were associated with within-pair differences in total body, leg and spine BMC, and cortical thickness. Every-hour-per-week difference in exercise was associated with a 31-g (1.2%) difference in total body BMC, a 10-g (1.4%) difference in leg BMC, a 0.5-g difference in spine BMC and a 0.1-mm difference in cortical thickness ( p <0.01- p <0.1). A 1-g difference in protein intake was associated with a 0.8-g (0.4%) difference in arm BMC ( p <0.05). These relationships were present in peri-pubertal and post-pubertal pairs but not in pre-pubertal pairs. Exercise during growth appears to have greater skeletal benefits than variations in protein or calcium intakes, with the site-specific effects evident in more mature twins.

Two-year changes in bone and body composition in young children with a history of prolonged milk avoidance

No previous longitudinal studies of calcium intake, anthropometry and bone health in young children with a history of avoiding cow's milk have been undertaken. We report the 2-year changes of a group of 46 Caucasian children (28 girls, l8 boys) aged 8.1+/-2.0 years (mean +/- SD) who had low calcium intakes at baseline and were short in stature, with elevated body mass index, poor skeletons and lower Z scores for both areal bone mineral density (BMD, in grams per square centimeter) and volumetric density (bone mineral apparent density, BMAD, in grams per cubic centimeter), compared with a reference population of milk drinkers. At follow-up, adverse symptoms to milk had diminished and modest increases in milk consumption and calcium intake had occurred. Total body bone mineral content (BMC) and bone area assessed by dual energy X-ray absorptiometry had increased (P<0.05), and calcium intake from all sources was associated with both these measures (P<0.05). However, although some catch-up in height had taken place, the group remained significantly shorter than the reference population (Z scores -0.39+/-1.14), with elevated body mass index (Z scores 0.46+/-1.0). The ultradistal radius BMC Z scores remained low (-0.31+/-0.98). The Z scores for BMD had improved to lie within the normal range at predominantly cortical sites (33% radius, neck of femur and hip trochanter) but had worsened at predominantly trabecular sites (ultradistal radius and lumbar spine), where values lay below those of the reference group (P<0.05). Similarly, although volumetric BMAD Z scores at the 33% radius had normalized, BMAD Z scores at the lumbar spine remained below the reference population at follow-up (-0.67+/-1.12, P<0.001). Our results demonstrate persisting height reduction, overweight and osteopenia at the ultradistal radius and lumbar spine in young milk avoiders over 2 years of follow-up.

Decreased osteoprotegerin and increased bone turnover in young female patients with major depressive disorder and a lifetime history of anorexia nervosa

Low bone mineral density (BMD) is a frequent, often persistent complication in patients with major depressive disorder (MDD) and anorexia nervosa (AN) that increases the risk of pathologic fractures. The pathogenetic process underlying osteopenia in MDD and AN is still unclear, although several factors, including a dysbalance of cytokines, are associated with loss of bone mass. Alterations in the serum levels of cytokines have been observed in patients with MDD, AN, and other psychiatric disorders. Therefore, we examined serum levels of cytokines, markers of bone turnover, and BMD in 13 patients with MDD and a lifetime history of AN. Bone turnover markers (osteocalcin and C-terminal degradation products of type I collagen) and tumor necrosis factor alpha (TNF-alpha) in patients were significantly increased compared with those of the control group. Osteoprotegerin (OPG) in patients was significantly decreased. Eight of 13 patients (62%) displayed osteopenia at the lumbar spine. TNF-alpha correlated significantly with C-terminal degradation products of type I collagen, an osteoclastic marker, but significantly negatively with OPG. Our data suggest that TNF-alpha and OPG may play a role in the pathogenetic process underlying osteopenia in these patients.

Is leptin the link between fat and bone mass?

Recently, leptin has emerged as a potential candidate responsible for protective effects of fat on bone tissue. However, it remains difficult to draw a clear picture of leptin effects on bone metabolism because published data are sometimes conflicting or apparently contradictory. Beyond differences in models or experimental procedures, it is tempting to hypothesize that leptin exerts dual effects depending on bone tissue, skeletal maturity, and/or signaling pathway. Early in life, leptin could stimulate bone growth and bone size through direct angiogenic and osteogenic effects on stromal precursor cells. Later, it may decrease bone remodeling in the mature skeleton, when trabecular bone turnover is high, by stimulating osteoprotegerin (OPG) expression. Leptin negative effects on bone formation effected through central nervous system pathway could counterbalance these peripheral and positive effects, the latter being predominant when the blood-brain barrier permeability decreases or the serum leptin level rises above a certain threshold. Thus, the sex-dependent specificity of the relationship between leptin and bone mineral density (BMD) in human studies could be, at least in part, caused by serum leptin levels that are two- to threefold higher in women than in men, independent of adiposity. Although these hypotheses remain highly speculative and require further investigations, existing studies consistently support the role of leptin as a link between fat and bone.

Prospective 10-year study of the determinants of bone density and bone loss in normal postmenopausal women, including the effect of hormone replacement therapy

OBJECTIVE

To prospectively assess bone density and the factors determining the rate of bone loss over a 10-year period of postmenopausal life.

DESIGN

Prospective, observational study.

METHODS

One hundred and four normal White postmenopausal women, baseline mean age 59 years (range 47-71 years) completed the study (mean duration of follow-up 10.2 years, range 9.4-10.6 years). None had diseases or were taking medications affecting bone metabolism at entry to the study. Information was collected on medical, fracture and smoking history, alcohol use, dietary calcium intake and physical activity. Body composition and bone density were measured by dual-energy X-ray absorptiometry at baseline and at 10 years. Biochemical, haematological and hormonal analyses were performed.

RESULTS

Twenty-four percent of the women started hormone replacement therapy (HRT) during the study period; most of these remained on therapy at follow-up. The mean duration of therapy was 6.6 years (range 2.8-10.4 years). The use of HRT was associated with significant gains in bone density (total body + 3.0%, trochanter + 4.2%, Ward's triangle + 4.4%, spine + 10.5%) and a significant reduction in vertebral fracture risk [standardized risk ratio compared with non-HRT users 0.42 (confidence interval 0.18-0.83)]. HRT use was not associated with greater weight gain than that occurring in other members of the cohort. The baseline and follow-up bone densities in the non-HRT users were highly correlated (0.82 < or = r < or = 0.91, P < or = 0.0001) and baseline bone density accounted for the majority of the variance in the 10-year results. Multivariate analyses showed that the independent correlates of rate of change of bone density were weight and fat mass (both baseline values and changes during follow-up), time after menopause, sex hormone concentrations, urinary calcium loss, PTH levels and haemoglobin concentration (which may reflect nutrition and health).

CONCLUSIONS

Bone density is highly predictable over an extended period of time in normal postmenopausal women. Maintenance of body weight and good health reduce bone loss. HRT is effective for treating osteoporosis, with improvement in bone density and reduction in vertebral fractures. Good compliance with HRT long-term is achievable. These findings are relevant to deciding the frequency of bone density measurement, and in advising women regarding prevention and treatment of postmenopausal bone loss.

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.

Leptin reduces ovariectomy-induced bone loss in rats

Bone mineral density increases with fat body mass, and obesity has a protective effect against osteoporosis. However, the relationship between fat body mass and bone mineral density is only partially explained by a combination of hormonal and mechanical factors. Serum leptin levels are strongly and directly related to fat body mass. We report here the effects of leptin administration compared with estrogen therapy on ovariectomy-induced bone loss in rats. Leptin was effective at reducing trabecular bone loss, trabecular architectural changes, and periosteal bone formation. Interestingly, the combination of estrogen and leptin further decreased bone turnover compared with that in estrogen-treated ovariectomized rats. Leptin also significantly increased osteoprotegerin mRNA steady state levels and protein secretion and decreased RANK ligand mRNA levels in human marrow stromal cells in vitro. Our findings suggest that leptin could modulate bone remodeling in favor of a better bone balance in rats. This study is the first evidence that leptin therapy has a significant effect in preventing ovariectomy-induced bone loss, and this effect may at least in part be mediated by the osteoprotegerin/RANK ligand pathway.