Fracture Risk in Patients with Anorexia Nervosa Over a 40-Year Period

Researchers have reported increased fracture risk in patients with anorexia nervosa (AN), but more knowledge on the long-term risk and the effects of age, male sex, and time-related changes is still needed. We examined the long-term (up to 40 years) fracture risk among patients with AN compared to a matched comparison cohort from the general population. We utilized data from the Danish Health Care Registers to identify 14,414 patients with AN (13,474 females and 940 males) diagnosed between 1977 and 2018, with a median age of 18.6 years and median follow-up time of 9.65 years. We calculated adjusted hazard ratios (aHRs) with 95% confidence intervals (CIs) using Cox regression analysis for overall and site-specific fracture risks. The overall aHR of any fracture was 1.46 [95% CI: 1.36 to 1.48], with an aHR of 1.50 [95% CI: 1.43 to 1.57] for females and 0.95 [95% CI: 0.82 to 1.1] for males. For specific fractures we found an association with femur fractures both in females 4.06 [95% CI: 3.39 to 4.46] and in males 2.79 [95% CI: 1.45 to 2.37] and for fractures of the spine (females 2.38 [95% CI: 2.00 to 2.84], males 2.31 [95% CI: 1.20 to 4.42]). The aHR of any fracture decreased from 1.66 [95% CI: 1.52 to 1.81] in the period from 1977 to 1997 to 1.40 [95% CI: 1.33 to 1.40] from 1998 to 2018. In conclusion, we found that AN was associated with a 46% increased risk of any fracture up to 40 years after diagnosis. We found no overall increased risk in males, but in both sexes we found a particularly high site-specific fracture risk in the spine and femur. Fracture risk decreased in recent decades, indicating that more patients with AN have been diagnosed with presumably less severe disease and that the earlier detection and intervention of AN in recent years may translate into a lower facture risk. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Red and White Blood Cell Counts Are Associated With Bone Marrow Adipose Tissue, Bone Mineral Density, and Bone Microarchitecture in Premenopausal Women

Bone marrow adipose tissue (BMAT) resides within the bone marrow microenvironment where its function remains poorly understood. BMAT is elevated in anorexia nervosa, a disease model of chronic starvation, despite depletion of other fat depots. In addition to BMAT, the marrow microenvironment also consists of osteoblast and hematopoietic progenitors. BMAT is inversely associated with bone mineral density (BMD) in multiple populations including women with anorexia nervosa, and regulates hematopoiesis in animal models. We hypothesized that BMAT would be associated with circulating populations of hematopoietic cells (red and white blood cells) in humans and performed a post hoc analysis of two studies-a cross-sectional study and a longitudinal study-to investigate this hypothesis. We studied 89 premenopausal women cross-sectionally (median age [interquartile range], 27 [24.5, 31.7] years), including 35 with anorexia nervosa. We investigated associations between red blood cell (RBC) and white blood cell (WBC) counts and BMAT assessed by 1 H-magnetic resonance spectroscopy, BMD assessed by DXA, and bone microarchitecture assessed by HR-pQCT. In addition, we analyzed longitudinal data in six premenopausal women with anorexia nervosa treated with transdermal estrogen for 6 months and measured changes in BMAT and blood cell counts during treatment. Cross-sectionally, BMAT was inversely associated with WBC and RBC counts. In contrast, BMD and parameters of bone microarchitecture were positively associated with WBC and RBC. In women with anorexia nervosa treated with transdermal estrogen for 6 months, decreases in BMAT were significantly associated with increases in both RBC and hematocrit (rho = -0.83, p = 0.04 for both). In conclusion, we show that BMAT is inversely associated with WBC and RBC in premenopausal women, and there is a potential association between longitudinal changes in BMAT and changes in RBC. These associations warrant further study and may provide further insight into the role and function of this understudied adipose depot. © 2020 American Society for Bone and Mineral Research.

Transdermal Estrogen in Women With Anorexia Nervosa: An Exploratory Pilot Study

Anorexia nervosa (AN) is a psychiatric disorder characterized by self‐induced starvation, low body weight, and elevated levels of bone marrow adipose tissue (BMAT). BMAT is negatively associated with BMD in AN and more than 85% of women with AN have low bone mass and an increased risk of fracture. Although a majority of women with AN are amenorrheic, which is associated with low BMD, oral contraceptive pills, containing supraphysiologic doses of estrogen, are not effective in increasing bone mass. We performed a 6‐month, open‐label study of transdermal estradiol (0.045 mg/day) + levonorgestrel (0.015 mg/day) in 11 women with AN (mean age ± SEM: 37.2 ± 2.3 years) to investigate the effects of transdermal, physiologic doses of estrogen on BMD and BMAT in women with AN. We measured change in BMD by DXA, change in BMAT at the spine/hip by ¹H‐magnetic resonance spectroscopy, and change in C‐terminal collagen cross‐links (CTX), P1NP, osteocalcin, IGF‐1, and sclerostin after 3 and 6 months of transdermal estrogen. Lumbar spine (2.0% ± 0.8%; p = 0.033) and lateral spine (3.2% ± 1.1%; p = 0.015) BMD increased after 6 months of transdermal estrogen. Lumbar spine BMAT decreased significantly after 3 months (−13.9 ± 6.0%; p = 0.046). Increases in lateral spine BMD were associated with decreases in CTX (p = 0.047). In conclusion, short‐term treatment with transdermal, physiologic estrogen increases spine BMD in women with AN. Future studies are needed to assess the long‐term efficacy of this treatment. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Assessment of Sex Differences in Fracture Risk Among Patients With Anorexia Nervosa: A Population-Based Cohort Study Using The Health Improvement Network

Though previous studies have demonstrated an increased fracture risk in females with anorexia nervosa (AN), fracture risk in males is not well characterized. The objective of this study was to examine sex differences in fracture risk and site-specific fracture incidence in AN. We performed a population-based retrospective cohort study using The Health Improvement Network (THIN; a large database of anonymized electronic medical records collected at primary care clinics throughout the United Kingdom). The median calendar year for the start of the observation period was 2004-2005. We identified 9239 females and 556 males <60 years of age with AN, and 97,889 randomly selected sex-, age-, and practice-matched participants without eating disorders (92,329 females and 5560 males). Multivariable Cox regression was used to estimate the hazard ratio (HR) for incident fracture. Median age at start of observation was 29.8 years in females and 30.2 years in males. The HR for fracture associated with AN differed by sex and age (interaction p = 0.002). Females with AN had an increased fracture risk at all ages (HR, 1.59; 95% confidence interval [CI], 1.45 to 1.75). AN was associated with a higher risk of fracture among males >40 years of age (HR, 2.54; 95% CI, 1.32 to 4.90; p = 0.005) but not among males ≤40 years. Females with AN had a higher risk of fracture at nearly all anatomic sites. The greatest excess fracture risk was noted at the hip/femur (HR, 5.59; 95% CI, 3.44 to 9.09) and pelvis (HR, 4.54; 95% CI, 2.42 to 8.50) in females and at the vertebrae (HR, 7.25; 95% CI, 1.21 to 43.45) for males with AN. AN was associated with higher incident fracture risk in females across all age groups and in males >40 years old. Sites of highest fracture risk include the hip/femur and pelvis in females and vertebrae in males with AN. © 2016 American Society for Bone and Mineral Research.

Does hormone replacement normalize bone geometry in adolescents with anorexia nervosa?

Young women with anorexia nervosa (AN) have reduced secretion of dehydroepiandrosterone (DHEA) and estrogen contributing to skeletal deficits. In this randomized, placebo-controlled trial, we investigated the effects of oral DHEA + combined oral contraceptive (COC) versus placebo on changes in bone geometry in young women with AN. Eighty women with AN, aged 13 to 27 years, received a random, double-blinded assignment to micronized DHEA (50 mg/day) + COC (20 µg ethinyl estradiol/0.1 mg levonorgestrel) or placebo for 18 months. Measurements of areal bone mineral density (aBMD) at the total hip were obtained by dual-energy X-ray absorptiometry at 0, 6, 12, and 18 months. We used the Hip Structural Analysis (HSA) program to determine BMD, cross-sectional area (CSA), and section modulus at the femoral neck and shaft. Each measurement was expressed as a percentage of the age-, height-, and lean mass-specific mean from an independent sample of healthy adolescent females. Over the 18 months, DHEA + COC led to stabilization in femoral shaft BMD (0.0 ± 0.5% of normal mean for age, height, and lean mass/year) compared with decreases in the placebo group (-1.1 ± 0.5% per year, p = 0.03). Similarly, CSA, section modulus, and cortical thickness improved with treatment. In young women with AN, adrenal and gonadal hormone replacement improved bone health and increased cross-sectional geometry. Our results indicate that this combination treatment has a beneficial impact on surrogate measures of bone strength, and not only bone density, in young women with AN.

CHRONIC ANOREXIA: A BEHAVIOUR PROBLEM

The chronic refusal to eat sometimes referred to as chronic anorexia can be effectively controlled through techniques developed in the behavioural laboratory. Contemporary methods used to reinstate normal eating such as persuasion, coaxing, spoon-feeding, insulin injections, tube-feeding, and others, can result in the patient being shaped or conditioned to eat only with assistance.

Based on an experimental investigation of erratic eating in mental patients, the authors present a behavioural model for the identification and treatment of chronic refusal to eat. The syndrome of chronic anorexia is regarded largely as the acquired, learned, behaviour of rejecting food. When food rejection is not followed by social reinforcement it disappears in a relatively short period of time, and normal eating is reinstated.