The Anorexia Nervosa Genetics Initiative (ANGI): Overview and methods

Prenatal antidepressant exposure and the risk of decreased gestational age and lower birthweight: A polygenic score approach to investigate confounding by indication

INTRODUCTION

Prenatal antidepressant exposure has been associated with lower gestational age and birthweight. Yet, unmeasured residual confounding may inflate this association. We explored if maternal genetic liability for major depression explains part of the association of antidepressant use in pregnancy with lower gestational age and birthweight.

MATERIAL AND METHODS

We employed the maternal polygenic score (PGS) for major depression as a measure of genetic liability. We used generalised linear models to estimate the differences in gestational age and birthweight at each PGS quintile between children whose mothers continued antidepressant use during pregnancy (continuation group), children whose mothers discontinued antidepressant use during pregnancy (discontinuation group) and unexposed children.

RESULTS

After adjusting for confounders, we found significant differences in birthweight between PGS quintiles in the continuation and unexposed group. Yet, this relationship was not linear. Furthermore, at the lowest and highest PGS quintiles, the continuation group had significantly reduced mean gestational ages (adjusted β ranges: 1.7-4.5 days, p < 0.001-0.008) and lower mean birthweights (adjusted β ranges: 58.6-165.4 g, p = 0.001-0.008) than the discontinuation and unexposed groups.

CONCLUSION

We confirmed that antidepressant use in pregnancy was associated with small reductions in gestational age and birthweight but found that genetic liability for depression was not linearly associated with this risk. The causality of the observed associations could not be established due to the observational nature of the study. Residual confounding linked to the underlying disease was likely still present.

Behavioral separation of liking and wanting in response to olfactory and visual food cues

In real-world settings, food rewards are processed in parallel across several sensory modalities, but paradigms that compare contributions of different modalities are lacking. While odor perception in particular is frequently implicated in appetite regulation, the mechanisms by which food odors differentially evoke experiences of wanting and liking remain poorly understood. This study addressed this gap by dissociating liking from wanting responses for olfactory stimuli, and establishing commonalities and differences relative to the visual modality. In two separate experiments, participants (n1 = 37, n2 = 43) rated content-matched batteries of odors and pictures, respectively, for their ability to elicit pleasure (liking) and desire to eat (wanting). A third experiment (n3 = 39) utilized a combined olfactory-visual paradigm to test the separation of these dimensions in a multisensory context. Our results show that participants differentiated clearly and reliably between liking and wanting for both odors and pictures, as demonstrated by a high difference score between the two in non-food (high liking, low wanting), but not in food (both high) or disgusting stimuli (both low), and high within-session retest reliability. Higher variability for olfactory relative to visual assessments was observed and likely reflects well-established difficulties with odor object identification. Taken together, our study demonstrates that olfactory stimuli can be used in experimental settings to evoke separable experiences of liking and wanting for food and non-food stimuli. Manipulating these components independently across sensory modalities in experimental studies could generate novel insights into how olfactory and visual cues differentially contribute to anticipatory and consummatory food reward processing, in healthy and disordered eating.

Descriptives and genetic correlates of eating disorder diagnostic transitions and presumed remission in the Danish registry

Objective

Eating disorders (EDs) are serious psychiatric disorders with an estimated 3.3 million healthy life-years lost worldwide yearly. Understanding the course of illness, diagnostic transitions and remission, and their associated genetic correlates could inform both ED etiology and treatment. The authors investigated occurrences of ED transitions and presumed remission and their genetic correlates as captured by polygenic scores (PGSs) in a large Danish register-based cohort.

Methods

The sample compromised of 10,565 individuals with a diagnosis of anorexia nervosa (AN), bulimia nervosa (BN), or eating disorder not otherwise specified (EDNOS) with at least two registered hospital contacts between 1995 and 2018. Based on medical records, occurrence of diagnostic transitions and periods of presumed remission were identified. Associations between 422 PGS and diagnostic transitions and presumed remission were evaluated using Cox proportional hazard models.

Results

A minority of ED cases (14.1%-23.1%) experienced a diagnostic transition. Presumed remission ranged between 86.9%-89.8%. Higher (one SD increase) PGS for major depressive disorder and multisite chronic pain were positively associated with transitioning from AN to either BN or EDNOS. Higher PGS on a measure of body fat percentage and financial difficulties were positively associated with presumed remission from AN. Higher PGS for mood swings was positively associated with presumed remission from EDNOS whereas higher PGS for health rating showed the opposite.

Conclusions

The authors found that most ED patients did not experience diagnostic transitions but were more likely to experience a period of presumed remission. Both diagnostic transitions and presumed remission have significant polygenic component.

Assessing Avoidant/Restrictive Food Intake Disorder (ARFID) Symptoms Using the Nine Item ARFID Screen in >9000 Swedish Adults With and Without Eating Disorders

OBJECTIVE

The Nine Item ARFID Scale (NIAS) is a widely used measure assessing symptoms of avoidant/restrictive food intake disorder (ARFID). Previous studies suggest that individuals with eating disorders driven by shape/weight concerns also have elevated scores on the NIAS. To further describe NIAS scores among individuals with diverse current and previous eating disorders, we characterized NIAS scores in a large sample of individuals with eating disorders and evaluated overlap in symptoms measured by the NIAS and the Eating Disorder Examination-Questionnaire (EDE-Q) version 6.0.

METHOD

Our sample comprised 9148 participants from the Eating Disorders Genetics Initiative Sweden (EDGI-SE), who completed surveys including NIAS and EDE-Q. NIAS scores were calculated and compared by eating disorder diagnostic group using descriptive statistics and linear models.

RESULTS

Participants with current anorexia nervosa demonstrated the highest mean NIAS scores and had the greatest proportion (57.0%) of individuals scoring above a clinical cutoff on at least one of the NIAS subscales. Individuals with bulimia nervosa, binge-eating disorder, and other specified feeding or eating disorder also demonstrated elevated NIAS scores compared to individuals with no lifetime history of an eating disorder (ps < 0.05). All subscales of the NIAS showed small to moderate correlations with all subscales of the EDE-Q (rs = 0.26-0.40).

DISCUSSION

Our results substantiate that individuals with eating disorders other than ARFID demonstrate elevated scores on the NIAS, suggesting that this tool is inadequate on its own for differentiating ARFID from shape/weight-motivated eating disorders. Further research is needed to inform clinical interventions addressing the co-occurrence of ARFID-related drivers and shape/weight-related motivation for dietary restriction.

Polygenic Risk of Mental Disorders and Subject-Specific School Grades

BACKGROUND

Education is essential for socioeconomic security and long-term mental health; however, mental disorders are often detrimental to the educational trajectory. Genetic correlations between mental disorders and educational attainment do not always align with corresponding phenotypic associations, implying heterogeneity in the genetic overlap.

METHODS

We unraveled this heterogeneity by investigating associations between polygenic risk scores for 6 mental disorders and fine-grained school outcomes: school grades in language and mathematics in ninth grade and high school, as well as educational attainment by age 25, using nationwide-representative data from established cohorts (N = 79,489).

RESULTS

High polygenic liability of attention-deficit/hyperactivity disorder was associated with lower grades in language and mathematics, whereas high polygenic risk of anorexia nervosa or bipolar disorder was associated with higher grades in language and mathematics. Associations between polygenic risk and school grades were mixed for schizophrenia and major depressive disorder and neutral for autism spectrum disorder.

CONCLUSIONS

Polygenic risk scores for mental disorders are differentially associated with language and mathematics school grades.

The role of co-occurring conditions and genetics in the associations of eating disorders with attention-deficit/hyperactivity disorder and autism spectrum disorder

Eating disorders (EDs) commonly co-occur with other psychiatric and neurodevelopmental disorders including attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD); however, the pattern of family history and genetic overlap among them requires clarification. This study investigated the diagnostic, familial, and genetic associations of EDs with ADHD and ASD. The nationwide population-based cohort study included all individuals born in Denmark, 1981-2008, linked to their siblings and cousins. Cox regression was used to estimate associations between EDs and ADHD or ASD, and mediation analysis was used to assess the effects of intermediate mood or anxiety disorders. Polygenic scores (PGSs) were used to investigate the genetic association between anorexia nervosa (AN) and ADHD or ASD. Significantly increased risk for any ED was observed following an ADHD [hazard ratio = 1.97, 95% confidence interval = 1.75-2.22] or ASD diagnosis [2.82, 2.48-3.19]. Mediation analysis suggested that intermediate mood or anxiety disorders could account for 44-100% of the association between ADHD or ASD and ED. Individuals with a full sibling or maternal halfsibling with ASD had increased risk of AN [1.54, 1.33-1.78; 1.45, 1.08-1.94] compared to those with siblings without ASD. A positive association was found between ASD-PGS and AN risk [1.06, 1.02-1.09]. In this study, positive phenotypic associations between EDs and ADHD or ASD, mediation by mood or anxiety disorder, and a genetic association between ASD-PGS and AN were observed. These findings could guide future research in the development of new treatments that can mitigate the development of EDs among individuals with ADHD or ASD.

Interplay of polygenic liability with birth-related, somatic, and psychosocial factors in anorexia nervosa risk: a nationwide study

BACKGROUND

Although several types of risk factors for anorexia nervosa (AN) have been identified, including birth-related factors, somatic, and psychosocial risk factors, their interplay with genetic susceptibility remains unclear. Genetic and epidemiological interplay in AN risk were examined using data from Danish nationwide registers. AN polygenic risk score (PRS) and risk factor associations, confounding from AN PRS and/or parental psychiatric history on the association between the risk factors and AN risk, and interactions between AN PRS and each level of target risk factor on AN risk were estimated.

METHODS

Participants were individuals born in Denmark between 1981 and 2008 including nationwide-representative data from the iPSYCH2015, and Danish AN cases from the Anorexia Nervosa Genetics Initiative and Eating Disorder Genetics Initiative cohorts. A total of 7003 individuals with AN and 45 229 individuals without a registered AN diagnosis were included. We included 22 AN risk factors from Danish registers.

RESULTS

Risk factors showing association with PRS for AN included urbanicity, parental ages, genitourinary tract infection, and parental socioeconomic factors. Risk factors showed the expected association to AN risk, and this association was only slightly attenuated when adjusted for parental history of psychiatric disorders or/and for the AN PRS. The interaction analyses revealed a differential effect of AN PRS according to the level of the following risk factors: sex, maternal age, genitourinary tract infection, C-section, parental socioeconomic factors and psychiatric history.

CONCLUSIONS

Our findings provide evidence for interactions between AN PRS and certain risk-factors, illustrating potential diverse risk pathways to AN diagnosis.

Maladaptive exercise in eating disorders: lifetime and current impact on mental health and treatment seeking

BACKGROUND

Many patients with eating disorders report exercise as a central symptom of their illness-as a way to compensate for food intake, prevent weight-gain, and/or reduce negative affect. Previous findings show associations between maladaptive exercise and more severe eating disorder pathology, higher risk for relapse, other co-morbid symptoms, and worse treatment outcome.

METHODS

In this study, we included 8252 participants with eating disorders and investigated associations between maladaptive exercise (both lifetime and current) and ED pathology, illness duration, depression, anxiety, self-harm and suicidal ideation, and treatment seeking patterns in individuals with lifetime maladaptive exercise. Participants were included via the Swedish site of the large global study The Eating Disorders Genetics Initiative (EDGI) and completed measures of both lifetime and current symptomatology.

RESULTS

Results indicate that lifetime maladaptive exercise is associated with higher prevalence of lifetime depression and anxiety and with patients more often receiving treatment, although these results need to be investigated in future studies. Current maladaptive exercise was associated with more severe ED symptoms, and higher levels of depression, anxiety, obsessive-compulsive traits, and suicidal ideation.

CONCLUSIONS

Our findings point to the complexities of exercise as an eating disorder symptom and the need for clearly assessing and acknowledging this, as well as tailoring interventions to treat this symptom to achieve sustainable recovery.

Shared familial risk for type 2 diabetes mellitus and psychiatric disorders: a nationwide multigenerational genetics study

BACKGROUND

Psychiatric disorders and type 2 diabetes mellitus (T2DM) are heritable, polygenic, and often comorbid conditions, yet knowledge about their potential shared familial risk is lacking. We used family designs and T2DM polygenic risk score (T2DM-PRS) to investigate the genetic associations between psychiatric disorders and T2DM.

METHODS

We linked 659 906 individuals born in Denmark 1990-2000 to their parents, grandparents, and aunts/uncles using population-based registers. We compared rates of T2DM in relatives of children with and without a diagnosis of any or one of 11 specific psychiatric disorders, including neuropsychiatric and neurodevelopmental disorders, using Cox regression. In a genotyped sample (iPSYCH2015) of individuals born 1981-2008 (n = 134 403), we used logistic regression to estimate associations between a T2DM-PRS and these psychiatric disorders.

RESULTS

Among 5 235 300 relative pairs, relatives of individuals with a psychiatric disorder had an increased risk for T2DM with stronger associations for closer relatives (parents:hazard ratio = 1.38, 95% confidence interval 1.35-1.42; grandparents: 1.14, 1.13-1.15; and aunts/uncles: 1.19, 1.16-1.22). In the genetic sample, one standard deviation increase in T2DM-PRS was associated with an increased risk for any psychiatric disorder (odds ratio = 1.11, 1.08-1.14). Both familial T2DM and T2DM-PRS were significantly associated with seven of 11 psychiatric disorders, most strongly with attention-deficit/hyperactivity disorder and conduct disorder, and inversely with anorexia nervosa.

CONCLUSIONS

Our findings of familial co-aggregation and higher T2DM polygenic liability associated with psychiatric disorders point toward shared familial risk. This suggests that part of the comorbidity is explained by shared familial risks. The underlying mechanisms still remain largely unknown and the contributions of genetics and environment need further investigation.

The United Kingdom Eating Disorders Genetics Initiative

OBJECTIVE

The United Kingdom Eating Disorders Genetics Initiative (EDGI UK), part of the National Institute for Health and Care Research (NIHR) Mental Health BioResource, aims to deepen our understanding of the environmental and genetic etiology of eating disorders. EDGI UK launched in February 2020 and is partnered with the UK eating disorders charity, Beat. Multiple EDGI branches exist worldwide. This article serves the dual function of providing an in-depth description of our study protocol and of describing our initial sample including demographics, diagnoses, and physical and psychiatric comorbidities.

METHOD

EDGI UK recruits via media and clinical services. Anyone living in England, at least 16 years old, with a lifetime probable or clinical eating disorder is eligible to sign up online: edgiuk.org. Participants complete online questionnaires, donate a saliva sample for genetic analysis, and consent to medical record linkage and recontact for future studies.

RESULTS

As of September 2022, EDGI UK recruited 7435 survey participants: 98% female, 93.1% white, 97.8% cisgender, 65.9% heterosexual, and 52.1% have a university degree. Over half (57.8%) of these participants have returned their saliva DNA kit. The most common diagnoses are anorexia nervosa (48.3%), purging disorder (37.8%), bulimia nervosa (37.5%), binge-eating disorder (15.8%), and atypical anorexia nervosa (7.8%).

CONCLUSION

EDGI UK is the largest UK eating disorders study and efforts to increase its diversity are underway. It offers a unique opportunity to accelerate eating disorder research. Researchers and participants with lived experience can collaborate on projects with unparalleled sample size.

PUBLIC SIGNIFICANCE STATEMENT

Eating disorders are debilitating and costly for society but are under-researched due to underfunding. EDGI UK is one of the largest eating disorder studies worldwide with ongoing recruitment. The collected data constitute a resource for secondary analysis. We will combine data from all international EDGI branches and the NIHR BioResource to facilitate research that improves our understanding of eating disorders and their comorbidities.

Inclusion of the severe and enduring anorexia nervosa phenotype in genetics research: a scoping review

BACKGROUND

Anorexia nervosa has one of the highest mortality rates of all mental illnesses. For those who survive, less than 70% fully recover, with many going on to develop a more severe and enduring phenotype. Research now suggests that genetics plays a role in the development and persistence of anorexia nervosa. Inclusion of participants with more severe and enduring illness in genetics studies of anorexia nervosa is critical.

OBJECTIVE

The primary goal of this review was to assess the inclusion of participants meeting the criteria for the severe enduring anorexia nervosa phenotype in genetics research by (1) identifying the most widely used defining criteria for severe enduring anorexia nervosa and (2) performing a review of the genetics literature to assess the inclusion of participants meeting the identified criteria.

METHODS

Searches of the genetics literature from 2012 to 2023 were performed in the PubMed, PsycINFO, and Web of Science databases. Publications were selected per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). The criteria used to define the severe and enduring anorexia nervosa phenotype were derived by how often they were used in the literature since 2017. The publications identified through the literature search were then assessed for inclusion of participants meeting these criteria.

RESULTS

most prevalent criteria used to define severe enduring anorexia nervosa in the literature were an illness duration of ≥ 7 years, lack of positive response to at least two previous evidence-based treatments, a body mass index meeting the Diagnostic and Statistical Manual of Mental Disorders-5 for extreme anorexia nervosa, and an assessment of psychological and/or behavioral severity indicating a significant impact on quality of life. There was a lack of consistent identification and inclusion of those meeting the criteria for severe enduring anorexia nervosa in the genetics literature.

DISCUSSION

This lack of consistent identification and inclusion of patients with severe enduring anorexia nervosa in genetics research has the potential to hamper the isolation of risk loci and the development of new, more effective treatment options for patients with anorexia nervosa.

Diagnosed eating disorders in Danish registers - incidence, prevalence, mortality, and polygenic risk

Eating disorders are a group of severe and potentially enduring psychiatric disorders associated with increased mortality. Compared to other severe mental illnesses, they have received relatively limited research attention. Epidemiological studies often only report relative measures despite these being difficult to interpret having limited practical use. The aims of this study were to evaluate the incidence and prevalence of diagnosed anorexia nervosa (AN), bulimia nervosa, and eating disorder not otherwise specified recorded in Danish hospital registers and estimate both relative and absolute measures of subsequent mortality - both all-cause and cause-specific in a general nationwide population of 1,667,374 individuals. In a smaller, genetically informed case-cohort sample, the prediction of polygenic scores for AN, body fat percentage, and body mass index on AN prevalence and severity was estimated. Despite males being less likely to be diagnosed with an eating disorder, those that do have significantly increased rates of mortality. AN prevalence was highest for individuals with high AN and low body fat percentage/body mass index polygenic scores.

Meta-analysis of ACE inhibitor-induced angioedema identifies novel risk locus

BACKGROUND

Angioedema is a rare but potentially life-threatening adverse drug reaction in patients receiving angiotensin-converting enzyme inhibitors (ACEis). Research suggests that susceptibility to ACEi-induced angioedema (ACEi-AE) involves both genetic and nongenetic risk factors. Genome- and exome-wide studies of ACEi-AE have identified the first genetic risk loci. However, understanding of the underlying pathophysiology remains limited.

OBJECTIVE

We sought to identify further genetic factors of ACEi-AE to eventually gain a deeper understanding of its pathophysiology.

METHODS

By combining data from 8 cohorts, a genome-wide association study meta-analysis was performed in more than 1000 European patients with ACEi-AE. Secondary bioinformatic analyses were conducted to fine-map associated loci, identify relevant genes and pathways, and assess the genetic overlap between ACEi-AE and other traits. Finally, an exploratory cross-ancestry analysis was performed to assess shared genetic factors in European and African-American patients with ACEi-AE.

RESULTS

Three genome-wide significant risk loci were identified. One of these, located on chromosome 20q11.22, has not been implicated previously in ACEi-AE. Integrative secondary analyses highlighted previously reported genes (BDKRB2 [bradykinin receptor B2] and F5 [coagulation factor 5]) as well as biologically plausible novel candidate genes (PROCR [protein C receptor] and EDEM2 [endoplasmic reticulum degradation enhancing alpha-mannosidase like protein 2]). Lead variants at the risk loci were found with similar effect sizes and directions in an African-American cohort.

CONCLUSIONS

The present results contributed to a deeper understanding of the pathophysiology of ACEi-AE by (1) providing further evidence for the involvement of bradykinin signaling and coagulation pathways and (2) suggesting, for the first time, the involvement of the fibrinolysis pathway in this adverse drug reaction. An exploratory cross-ancestry comparison implicated the relevance of the associated risk loci across diverse ancestries.

New understandings meet old treatments: putting a contemporary face on established protocols

In the twenty years since the publication of the most widely used treatment manuals describing evidence-based therapies for eating disorders, there have been some substantial advances in the field. New methods of delivering treatments have been trialled and our perception of mental health has advanced; significant cultural changes have led to shifts in our societal landscape; and new technologies have allowed for more in-depth research to be conducted. As a result, our understanding of eating disorders and their treatment has broadened considerably. However, these new insights have not necessarily been translated into improved clinical practice. This paper highlights the changes we consider to have had the greatest impact on our work as experienced clinical psychologists in the field and suggests a list of new learnings that might be incorporated into clinical practice and research design.

Adaptive and Maladaptive Exercise in Eating Disorders

While exercise is generally associated with positive health outcomes, in the context of eating disorders, exercise has high potential to become maladaptive. Maladaptive exercise is compelled or compulsive in nature for the purposes of weight and shape control or to obtain/avoid other eating disorder-relevant consequences. A transdiagnostic eating disorder feature with moderate-to-high prevalence across restrictive- and bulimic-spectrum eating disorders, maladaptive exercise is often associated with negative mental and physical health sequalae. Several proposed threat- and reward-related biobehavioral mechanisms may initiate or perpetuate maladaptive exercise. While exercise is generally contraindicated during periods of acute medical concern, adaptive forms of exercise are also present among those with eating disorders, and facilitation of adaptive exercise has potential to promote physical and mental health benefits during eating disorder recovery. Detailed assessment and targeted interventions are needed to address the clinical conundrum of how and when to integrate exercise into eating disorder treatment.

Persistent thinness and anorexia nervosa differ on a genomic level

Thinness and anorexia nervosa are both characterised by persistent low weight. Individuals with anorexia nervosa concurrently report distorted perceptions of their body and engage in weight-loss behaviours, whereas individuals with thinness often wish to gain weight. Both conditions are heritable and share genomics with BMI, but are not genetically correlated with each other. Based on their pattern of genetic associations with other traits, we explored differences between thinness and anorexia nervosa on a genomic level. In Part 1, using publicly available data, we compared genetic correlations of persistent thinness/anorexia nervosa with eleven psychiatric disorders. In Part 2, we identified individuals with adolescent persistent thinness in the Avon Longitudinal Study of Parents and Children (ALSPAC) by latent class growth analysis of measured BMI from 10 to 24 years (n = 6594) and evaluated associations with psychiatric and anthropometric polygenic scores. In Part 1, in contrast to the positive genetic correlations of anorexia nervosa with various psychiatric disorders, persistent thinness showed negative genetic correlations with attention deficit hyperactivity disorder (rgAN = 0.08 vs. rgPT = -0.30), alcohol dependence (rgAN = 0.07 vs. rgPT = -0.44), major depressive disorder (rgAN = 0.27 vs. rgPT = -0.18) and post-traumatic stress disorder (rgAN = 0.26 vs. rgPT = -0.20). In Part 2, individuals with adolescent persistent thinness in the ALSPAC had lower borderline personality disorder polygenic scores (OR = 0.77; Q = 0.01). Overall, results suggest that genetic variants associated with thinness are negatively associated with psychiatric disorders and therefore thinness may be differentiable from anorexia nervosa on a genomic level.

The correlates of neonatal complement component 3 and 4 protein concentrations with a focus on psychiatric and autoimmune disorders

Complement components have been linked to schizophrenia and autoimmune disorders. We examined the association between neonatal circulating C3 and C4 protein concentrations in 68,768 neonates and the risk of six mental disorders. We completed genome-wide association studies (GWASs) for C3 and C4 and applied the summary statistics in Mendelian randomization and phenome-wide association studies related to mental and autoimmune disorders. The GWASs for C3 and C4 protein concentrations identified 15 and 36 independent loci, respectively. We found no associations between neonatal C3 and C4 concentrations and mental disorders in the total sample (both sexes combined); however, post-hoc analyses found that a higher C3 concentration was associated with a reduced risk of schizophrenia in females. Mendelian randomization based on C4 summary statistics found an altered risk of five types of autoimmune disorders. Our study adds to our understanding of the associations between C3 and C4 concentrations and subsequent mental and autoimmune disorders.

The impact of genetic risk for schizophrenia on eating disorder clinical presentations

A growing body of literature recognizes associations between eating disorders (EDs) and schizophrenia and suggests that familial liability to schizophrenia in individuals with anorexia nervosa (AN) reveals distinct patterns of clinical outcomes. To further investigate the influence of schizophrenia genetic liability among individuals with EDs, we evaluated the associations between schizophrenia polygenic risk scores (PRS) and clinical presentations of individuals with EDs including their overall health condition and ED-related symptoms. Using data from two previous studies of the genetics of EDs comprising 3,573 Anorexia Nervosa Genetics Initiative (ANGI) cases and 696 Binge Eating Genetics Initiative (BEGIN) cases born after 1973 and linked to the Swedish National Patient Register, we examined the association of schizophrenia PRS on ED clinical features, psychiatric comorbidities, and somatic and mental health burden. Among ANGI cases, higher schizophrenia PRS was statistically significantly associated with higher risk of major depressive disorder (MDD) measured by hazard ratio (HR) with 95% confidence interval (CI) (HR [95% CI]: 1.07 [1.02, 1.13]) and substance abuse disorder (SUD) (HR [95% CI]: 1.14 [1.03, 1.25]) after applying multiple testing correction. Additionally, higher schizophrenia PRS was associated with decreased clinical impairment assessment scores (-0.56, 95% CI: [-1.04, -0.08]) at the conventional significance level (p < 0.05). Further, in BEGIN cases, higher schizophrenia PRS was statistically significantly associated with earlier age at first ED symptom (-0.35 year, 95% CI: [-0.64, -0.06]), higher ED symptom scores (0.16, 95% CI: [0.04, 0.29]), higher risk of MDD (HR [95% CI]: 1.18 [1.04, 1.34]) and SUD (HR [95% CI]: 1.36 [1.07, 1.73]). Similar, but attenuated, patterns held in the subgroup of exclusively AN vs other eating disorder (OED) cases. These results suggest a similar pattern of influence of schizophrenia PRS for AN and OED cases in terms of psychiatric comorbidities, but a different pattern in terms of ED-related clinical features. The disparity of the effect of schizophrenia PRS on AN vs OED merits further investigation.

ARFID Genes and Environment (ARFID-GEN): study protocol

BACKGROUND

The Avoidant Restrictive Food Intake Disorder - Genes and Environment (ARFID-GEN) study is a study of genetic and environmental factors that contribute to risk for developing ARFID in children and adults.

METHODS

A total of 3,000 children and adults with ARFID from the United States will be included. Parents/guardians and their children with ARFID (ages 7 to 17) and adults with ARFID (ages 18 +) will complete comprehensive online consent, parent verification of child assent (when applicable), and phenotyping. Enrolled participants with ARFID will submit a saliva sample for genotyping. A genome-wide association study of ARFID will be conducted.

DISCUSSION

ARFID-GEN, a large-scale genetic study of ARFID, is designed to rapidly advance the study of the genetics of eating disorders. We will explicate the genetic architecture of ARFID relative to other eating disorders and to other psychiatric, neurodevelopmental, and metabolic disorders and traits. Our goal is for ARFID to deliver "actionable" findings that can be transformed into clinically meaningful insights.

TRIAL REGISTRATION

ARFID-GEN is a registered clinical trial: clinicaltrials.gov NCT05605067.

Stressful life events and resilience in individuals with and without a history of eating disorders: a latent class analysis

BACKGROUND

Eating disorders (EDs) are associated with a range of stressful life events, but few have investigated protective factors that may affect these associations. The current study used mixture modelling to describe typologies in life stress exposure and availability of protective resources in individuals with and without eating disorders (EDs).

METHODS

A case - control sample (n = 916) completed measures of stressful life events, resilience protective factors, emotion regulation, and symptoms of EDs, depression and anxiety. We conducted latent class analyses to identify subgroups of stress exposure and profile analyses of emotional regulation and resilience. The resulting two latent variables were combined to explore effects on ED status and symptomatology, depression, and anxiety as distal outcome variables.

RESULTS

We identified four classes of stressful life events (generally low, some abuse/bullying, sexual/emotional assaults, and high adversity). For protective resources, we identified six profiles that ranged from low to higher levels of protection with variations in social/family resources. The latent protection variable contributed more strongly to the distal outcomes than the latent stress variable, but did not moderate the latent stress and distal outcome variable relationships. Profiles characterized by lower protective resources included higher proportions of individuals with a lifetime ED, and were associated with higher scores on all symptom measures.

CONCLUSIONS

Intra- and interpersonal protective resources were strongly associated with lifetime EDs and current mental health symptom burden after accounting for stressful event exposure, suggesting protective factors may be useful to target in the clinical treatment of patients with ED.

Laxative Abuse Is Associated With a Depleted Gut Microbial Community Structure Among Women and Men With Binge-Eating Disorder or Bulimia Nervosa: The Binge Eating Genetics Initiative

OBJECTIVE

This study assessed the associations of binge eating, compensatory behaviors, and dietary restraint with the composition and diversity of the intestinal microbiota among participants with binge-eating disorder or bulimia nervosa.

METHODS

We analyzed data from 265 participants aged 18 to 45 years with current binge-eating disorder or bulimia nervosa enrolled in the Binge Eating Genetics Initiative study. We evaluated the associations of binge-eating frequency; presence/absence and frequency of vomiting, laxative use, and compulsive exercise; and dietary restraint with abundances of gut microbial genera, species, and diversity (Shannon diversity, Faith phylogenetic diversity, and Peilou's evenness) from 16S rRNA gene sequencing. General linear regression models adjusted for potential confounders, including age and current body mass index, were used to test associations; p values were corrected for the false discovery rate.

RESULTS

The normalized abundance of four genus- and species-level gut microbes and three diversity indices were lower among Binge Eating Genetics Initiative participants who reported any laxative use compared with those who reported no laxative use. Vomiting frequency was positively associated with the normalized abundance of the genus Escherichia-Shigella , a potential pathobiont, although the association was attenuated to nonsignificance after adjustment for age, body mass index, and binge-eating episodes.

CONCLUSIONS

Laxative use was highly and uniformly predictive of a reduced gut microbial diversity including potential commensals and pathobionts, and should be assessed and accounted for in all future studies of eating disorders and the gut microbiota. Future studies should collect data on specific medications-particularly laxatives-and dietary intake to obtain unbiased estimates of the effect of eating disorders on the gut microbiota and identify potential downstream clinical implications.Trial Registration:ClinicalTrials.gov identifier: NCT04162574 .

Risk factors for anorexia nervosa: A population-based investigation of sex differences in polygenic risk and early life exposures

OBJECTIVE

To examine sex differences in risk factors for anorexia nervosa (AN).

METHOD

This population-based study involved 44,743 individuals (6,239 AN cases including 5,818 females and 421 males, and 38,504 controls including 18,818 females and 19,686 males) born in Denmark between May 1981 and December 2009. Follow-up began on the individual's sixth birthday and ended at AN diagnosis, emigration, death, or December 31, 2016, whichever occurred first. Exposures included socioeconomic status (SES), pregnancy, birth, and early childhood factors based on data from Danish registers, and psychiatric and metabolic polygenic risk scores (PRS) based on genetic data. Hazard ratios were estimated using weighted Cox proportional hazards models stratified by sex (assigned at birth), with AN diagnosis as the outcome.

RESULTS

The effects of early life exposures and PRS on AN risk were comparable between females and males. Although we observed some differences in the magnitude and direction of effects, there were no significant interactions between sex and SES, pregnancy, birth, or early childhood exposures. The effects of most PRS on AN risk were highly similar between the sexes. We observed significant sex-specific effects of parental psychiatric history and body mass index PRS, though these effects did not survive corrections for multiple comparisons.

CONCLUSIONS

Risk factors for AN are comparable between females and males. Collaboration across countries with large registers is needed to further investigate sex-specific effects of genetic, biological, and environmental exposures on AN risk, including exposures in later childhood and adolescence as well as the additive effects of exposures.

PUBLIC SIGNIFICANCE

Sex differences in the prevalence and clinical presentation of AN warrant examination of sex-specific risk factors. This population-based study indicates that the effects of polygenic risk and early life exposures on AN risk are comparable between females and males. Collaboration between countries with large registers is needed to further investigate sex-specific AN risk factors and improve early identification of AN.

Arfid Genes and Environment (ARFID-GEN): Study Protocol

Background

The Avoidant Restrictive Food Intake Disorder Genes and Environment (ARFID-GEN) study is a study of genetic and environmental factors that contribute to risk for developing ARFID in children and adults.

Methods

A total of 3,000 children and adults with ARFID from the United States will be included. Parents/guardians and their children with ARFID (ages 7 to 17) and adults with ARFID (ages 18+) will complete comprehensive online consent, parent verification of child assent (when applicable), and phenotyping. Enrolled participants with ARFID will submit a saliva sample for genotyping. A genome-wide association study of ARFID will be conducted.

Discussion

ARFID-GEN, a large-scale genetic study of ARFID, is designed to rapidly advance the study of the genetics of eating disorders. We will explicate the genetic architecture of ARFID relative to other eating disorders and to other psychiatric, neurodevelopmental, and metabolic disorders and traits. Our goal is for ARFID to deliver "actionable" findings that can be transformed into clinically meaningful insights.

Trial registration

ARFID-GEN is a registered clinical trial: clinicaltrials.gov NCT05605067.

Multi-PGS enhances polygenic prediction by combining 937 polygenic scores

The predictive performance of polygenic scores (PGS) is largely dependent on the number of samples available to train the PGS. Increasing the sample size for a specific phenotype is expensive and takes time, but this sample size can be effectively increased by using genetically correlated phenotypes. We propose a framework to generate multi-PGS from thousands of publicly available genome-wide association studies (GWAS) with no need to individually select the most relevant ones. In this study, the multi-PGS framework increases prediction accuracy over single PGS for all included psychiatric disorders and other available outcomes, with prediction R2 increases of up to 9-fold for attention-deficit/hyperactivity disorder compared to a single PGS. We also generate multi-PGS for phenotypes without an existing GWAS and for case-case predictions. We benchmark the multi-PGS framework against other methods and highlight its potential application to new emerging biobanks.

Sociodemographic and clinical characteristics of treated and untreated adults with bulimia nervosa or binge-eating disorder recruited for a large-scale research study

BACKGROUND

Eating disorders affect millions of people worldwide, but most never receive treatment. The majority of clinical research on eating disorders has focused on individuals recruited from treatment settings, which may not represent the broader population of people with eating disorders. This study aimed to identify potential differences in the characteristics of individuals with eating disorders based on whether they self-reported accessing treatment or not, in order to contribute to a better understanding of their diverse needs and experiences.

METHODS

The study population included 762 community-recruited individuals (85% female, M ± SD age = 30 ± 7 years) with bulimia nervosa or binge-eating disorder (BN/BED) enrolled in the Binge Eating Genetics Initiative (BEGIN) United States study arm. Participants completed self-report surveys on demographics, treatment history, past and current eating disorder symptoms, weight history, and their current mental health and gastrointestinal symptoms. Untreated participants (n = 291, 38%) were compared with treated participants (n = 471, 62%) who self-reported accessing BN/BED treatment at some point in their lives.

RESULTS

Untreated participants disproportionately self-identified as male and as a racial or ethnic minority compared with treated participants. Treated participants reported a more severe illness history, specifically, an earlier age at onset, more longstanding and frequent eating disorder symptoms over their lifetime, and greater body dissatisfaction and comorbid mental health symptoms (i.e., depression, anxiety, ADHD) at the time of the study. A history of anorexia nervosa was positively associated with treatment engagement. Individuals self-reporting a history of inpatient or residential treatment exhibited the most severe illness history, those with outpatient treatment had a less severe illness history, and untreated individuals had the mildest illness history.

CONCLUSIONS

Historically overlooked and marginalized populations self-reported lower treatment access rates, while those who accessed treatment reported more severe eating disorder and comorbid mental health symptoms, which may have motivated them to seek treatment. Clinic-based recruitment samples may not represent individuals with milder symptoms or racial and ethnic diversity, and males. Community-based recruitment is crucial for improving the ability to apply research findings to broader populations and reducing disparities in medical research. Trial Registration ClinicalTrials.gov NCT04162574 ( https://clinicaltrials.gov/ct2/show/NCT04162574 ).

Sociodemographic and Clinical Characteristics of Treated and Untreated Adults with Bulimia Nervosa and/or Binge-eating Disorder Recruited for a Large-Scale Research Study

Background: Eating disorders affect millions of people worldwide, but most never receive treatment. The majority of clinical research on eating disorders has focused on individuals recruited from treatment settings, which may not represent the broader population of people with eating disorders. This study compared the characteristics of individuals with eating disorders based on whether they self-reported accessing treatment or not, to identify potential differences and contribute to a better understanding of the diverse needs and experiences of individuals with eating disorders. Methods: The study population included 762 community-recruited individuals (85% female, M ± SD age = 30 ± 7 y) with bulimia nervosa and/or binge eating disorder (BN/BED) enrolled in the Binge-Eating Genetics Initiative (BEGIN) United States study arm. Participants completed self-report surveys on demographics, treatment history, past and current eating disorder symptoms, weight history, and current mental health and gastrointestinal comorbidity. Untreated participants ( n = 291, 38%) were compared with treated participants ( n = 471, 62%) who self-reported accessing BN/BED treatment at some point in their lives. Results: Untreated participants disproportionately self-identified as male and as a racial or ethnic minority compared with treated participants. Treated participants reported a more severe illness history, specifically, an earlier age at onset, more longstanding and frequent ED symptoms over their lifetime, and higher body dissatisfaction and comorbid mental health symptoms (i.e., depression, anxiety, ADHD) at the time of the study. Those who reported a history of inpatient or residential treatment displayed the most severe illness history, whereas those who reported outpatient treatment had a less severe illness history, and untreated individuals had the mildest illness history. Conclusions: Individuals from historically overlooked or marginalized populations were less likely to access treatment. Those who accessed treatment had more severe ED and comorbid symptoms, which may have motivated them to seek treatment. Clinic-based recruitment samples may not accurately represent all individuals with EDs, particularly those with milder symptoms and those with gender or racial/ethnic diversity. The results of this study indicate that community-based recruitment is crucial for improving the ability to apply research findings to broader populations and to reduce disparities in medical research. Trial Registration : ClinicalTrials.gov NCT04162574 (https://clinicaltrials.gov/ct2/show/NCT04162574).

Anorexia Nervosa in Adolescence: Parental Narratives Explore Causes and Responsibilities

BACKGROUND

Anorexia nervosa (AN) is a serious mental disorder with a multifactorial etiopathogenesis, adolescent girls being especially vulnerable. Parents can be a resource and occasionally a burden when their children suffer from AN; thus, parents play a key role in recovery. This study focused on parental illness theories of AN and how parents negotiate their responsibilities.

METHODS

To gain insights into this dynamic, 14 parents (11 mothers, 3 fathers) of adolescent girls were interviewed. Qualitative content analysis was used to provide an overview of the parents' assumed causes for their children's AN. We also looked for systematic differences in the assumed causes among different groups of parents (e.g., high versus low self-efficacy). A microgenetic positioning analysis of two mother-father dyads provided further insight into how they viewed the development of AN in their daughters.

RESULTS

The analysis stressed the overall helplessness of parents and their strong need to understand what was going on. Parents differed in stressing internal and external causes, which influenced whether they felt responsible and how much they felt in control and able to help.

CONCLUSIONS

Analysing the variability and dynamics shown can support therapists, especially those working systemically to change the narratives within families for better therapy compliance and outcomes.

Genetic correlates of vitamin D-binding protein and 25-hydroxyvitamin D in neonatal dried blood spots

The vitamin D binding protein (DBP), encoded by the group-specific component (GC) gene, is a component of the vitamin D system. In a genome-wide association study of DBP concentration in 65,589 neonates we identify 26 independent loci, 17 of which are in or close to the GC gene, with fine-mapping identifying 2 missense variants on chromosomes 12 and 17 (within SH2B3 and GSDMA, respectively). When adjusted for GC haplotypes, we find 15 independent loci distributed over 10 chromosomes. Mendelian randomization analyses identify a unidirectional effect of higher DBP concentration and (a) higher 25-hydroxyvitamin D concentration, and (b) a reduced risk of multiple sclerosis and rheumatoid arthritis. A phenome-wide association study confirms that higher DBP concentration is associated with a reduced risk of vitamin D deficiency. Our findings provide valuable insights into the influence of DBP on vitamin D status and a range of health outcomes.

Binge-eating disorder with and without lifetime anorexia nervosa: A comparison of sociodemographic and clinical features

OBJECTIVE

To compare individuals who have experienced binge-eating disorder (BED) and anorexia nervosa (AN) (BED AN+) to those who have experienced BED and not AN (BED AN-).

METHOD

Participants (N = 898) met criteria for lifetime BED and reported current binge eating. Approximately 14% had a lifetime diagnosis of AN. Analyses compared BED AN+ and BED AN- on sociodemographic variables and clinical history.

RESULTS

The presence of lifetime AN was associated with more severe eating disorder symptoms, including earlier onset, more frequent, more chronic, and more types of eating disorder behaviors over the lifetime, as well as a higher lifetime prevalence of bulimia nervosa (BN). Participants with lifetime AN reported being more likely to have received treatments for BED or BN, had significantly lower minimum, current, and maximum BMIs, had more severe general anxiety, and were significantly more likely to be younger and female. In the full sample, the lifetime prevalence of unhealthy weight control behaviors was high and treatment utilization was low, despite an average 15-year history since symptom onset. Gastrointestinal disorders and comorbid anxiety, depression, and attention-deficit/hyperactivity disorder symptoms were prevalent.

DISCUSSION

Individuals fared poorly on a wide array of domains, yet those with lifetime AN fared considerably more poorly. All patients with BED should be screened for mental health and gastrointestinal comorbidities and offered referral and treatment options.

PUBLIC SIGNIFICANCE

Individuals experiencing binge-eating disorder have severe symptomology, but those who have experienced binge-eating disorder and anorexia nervosa fare even more poorly. Our study emphasizes that patients with binge-eating disorder would benefit from being screened for mental health and gastrointestinal comorbidities, and clinicians should consider history of unhealthy weight control behaviors to inform treatment and relapse prevention.

Eating disorders, disordered eating, and body image research in New Zealand: a scoping review

BACKGROUND

The prevention and treatment of eating disorders relies on an extensive body of research that includes various foci and methodologies. This scoping review identified relevant studies of eating disorders, body image, and disordered eating with New Zealand samples; charted the methodologies, sample characteristics, and findings reported; and identified several gaps that should be addressed by further research.

METHODS

Using scoping review methodology, two databases were searched for studies examining eating disorders, disordered eating, or body image with New Zealand samples. Snowball methods were further used to identify additional relevant articles that did not appear in initial searches. Two independent reviewers screened the titles and abstracts of 473 records. Full text assessment of the remaining 251 records resulted in 148 peer-reviewed articles being identified as eligible for the final review. A search of institutional databases yielded 106 Masters and Doctoral theses for assessment, with a total of 47 theses being identified as eligible for the final review. The included studies were classified by methodology, and the extracted information included the study foci, data collected, sample size, demographic information, and key findings.

RESULTS

The eligible studies examined a variety of eating disorder categories including binge-eating disorder, bulimia nervosa, and anorexia nervosa, in addition to disordered eating behaviours and body image in nonclinical or community samples. Methodologies included treatment trials, secondary analysis of existing datasets, non-treatment experimental interventions, cross-sectional observation, case-control studies, qualitative and mixed-methods studies, and case studies or series. Across all of the studies, questionnaire and interview data were most commonly utilised. A wide range of sample sizes were evident, and studies often reported all-female or mostly-female participants, with minimal inclusion of males and gender minorities. There was also an underrepresentation of minority ethnicities in many studies, highlighting the need for future research to increase diversity within samples.

CONCLUSION

This study provides a comprehensive and detailed overview of research into eating disorders and body image in New Zealand, while highlighting important considerations for both local and international research.

Genome-wide association study of school grades identifies genetic overlap between language ability, psychopathology and creativity

Cognitive functions of individuals with psychiatric disorders differ from that of the general population. Such cognitive differences often manifest early in life as differential school performance and have a strong genetic basis. Here we measured genetic predictors of school performance in 30,982 individuals in English, Danish and mathematics via a genome-wide association study (GWAS) and studied their relationship with risk for six major psychiatric disorders. When decomposing the school performance into math and language-specific performances, we observed phenotypically and genetically a strong negative correlation between math performance and risk for most psychiatric disorders. But language performance correlated positively with risk for certain disorders, especially schizophrenia, which we replicate in an independent sample (n = 4547). We also found that the genetic variants relating to increased risk for schizophrenia and better language performance are overrepresented in individuals involved in creative professions (n = 2953) compared to the general population (n = 164,622). The findings together suggest that language ability, creativity and psychopathology might stem from overlapping genetic roots.

Risk and protective factors for new-onset binge eating, low weight, and self-harm symptoms in >35,000 individuals in the UK during the COVID-19 pandemic

OBJECTIVE

The disruption caused by the COVID-19 pandemic has been associated with poor mental health, including increases in eating disorders and self-harm symptoms. We investigated risk and protective factors for the new onset of these symptoms during the pandemic.

METHOD

Data were from the COVID-19 Psychiatry and Neurological Genetics study and the Repeated Assessment of Mental health in Pandemics Study (n = 36,715). Exposures were socio-demographic characteristics, lifetime psychiatric disorder, and COVID-related variables, including SARS-CoV-2 infection/illness with COVID-19. We identified four subsamples of participants without pre-pandemic experience of our outcomes: binge eating (n = 24,211), low weight (n = 24,364), suicidal and/or self-harm ideation (n = 18,040), and self-harm (n = 29,948). Participants reported on our outcomes at frequent intervals (fortnightly to monthly). We fitted multiple logistic regression models to identify factors associated with the new onset of our outcomes.

RESULTS

Within each subsample, new onset was reported by: 21% for binge eating, 10.8% for low weight, 23.5% for suicidal and/or self-harm ideation, and 3.5% for self-harm. Shared risk factors included having a lifetime psychiatric disorder, not being in paid employment, higher pandemic worry scores, and being racially minoritized. Conversely, infection with SARS-CoV-2/illness with COVID-19 was linked to lower odds of binge eating, low weight, and suicidal and/or self-harm ideation.

DISCUSSION

Overall, we detected shared risk factors that may drive the comorbidity between eating disorders and self-harm. Subgroups of individuals with these risk factors may require more frequent monitoring during future pandemics.

PUBLIC SIGNIFICANCE

In a sample of 35,000 UK residents, people who had a psychiatric disorder, identified as being part of a racially minoritized group, were not in paid employment, or were more worried about the pandemic were more likely to experience binge eating, low weight, suicidal and/or self-harm ideation, and self-harm for the first time during the pandemic. People with these risk factors may need particular attention during future pandemics to enable early identification of new psychiatric symptoms.

Longer-term impact of COVID-19 among individuals with self-reported eating disorders in the United States, the Netherlands, and Sweden

OBJECTIVE

We assessed eating disorder (ED) illness status, symptomatology, treatment access, anxiety, and depression in the first year of the COVID-19 pandemic among individuals with a pre-existing ED in the United States (US), the Netherlands (NL), and Sweden (SE).

METHODS

Participants completed online surveys in April-July 2020, at the early stage of the pandemic, and one year later. At one-year follow-up, we added questions addressing retrospective changes in ED symptoms, treatment, and anxiety/depression since the start of the COVID-19 pandemic. We present descriptive statistics and assess change in ED symptomatology, treatment, and anxiety/depression among those with an active or lingering ED.

RESULTS

Participants (US n = 132; NL n = 219; SE n = 702) were mostly young and female with a history of anorexia nervosa (>60% in all three countries). Across countries, respondents reported impact of COVID-19 on ED symptoms at both time points, with improvement in US and NL at one-year follow-up, and stable but less impact on ED symptoms in SE. Furthermore, at one-year follow-up, roughly half of those in treatment reported reduced treatment access and quality, and the majority of the sample reported increased anxiety and depressive mood since the start of the pandemic.

DISCUSSION

Our findings suggest that the self-perceived impact of COVID-19 changed over time but remained concerning even one year after the start of the pandemic. Clinicians, community organizations, and policy makers are encouraged to address potentially changing treatment needs in the face of public health emergency events.

PUBLIC SIGNIFICANCE

Our findings suggest that the impact of COVID-19 on individuals with eating disorders decreased over time but remained concerning even one year after the start of the pandemic and that the impact differed across countries. Clinicians, community organizations, and policy makers are encouraged to incorporate this knowledge to address potentially changing treatment needs in the face of public health emergency events.

Course and predictors of eating disorder symptoms, anxiety symptoms, and pandemic-related eating disorder concerns among adults with eating disorders during the first year of the COVID-19 pandemic

OBJECTIVE

The COVID-19 pandemic and public health mitigation measures have negatively impacted individuals with eating disorders (ED). We evaluated changes in and predictors of ED symptoms, pandemic-related ED concerns, and anxiety symptoms across the first 12 months of the COVID-19 pandemic among individuals with self-reported EDs in the United States (US), Sweden (SE), and the Netherlands (NL).

METHOD

Participants in the US (N = 510), SE (N = 982), and NL (N = 510) completed an online survey assessing ED symptoms (binge eating, restriction, compensatory behaviors, and anxiety about being unable to exercise), general anxiety symptoms, and pandemic-related ED concerns about accessing food, lack of structure and social support, being in a triggering environment, and food and treatment costs. In the US and NL, respondents completed surveys beginning April 2020 and continuing monthly for a year. In SE, respondents completed baseline surveys in May 2020, a six-month follow-up around December 2020, and a 12-month follow-up in May 2021.

RESULTS

Three patterns emerged: (1) a curvilinear course with the highest level of symptoms at baseline, declining through November 2020, and increasing through the rest of the year; (2) a linear declining course over time; and (3) a stable course with no changes. Worries about COVID-19 infection, lockdown, concerns about lack of structure and social support, and concerns about accessing food consistent with one's recovery meal plan predicted increases in ED symptoms.

DISCUSSION

ED symptoms tracked with pandemic-related concerns in people with EDs. Conceptualizing predictors of symptoms may inform therapy and public health resources that reduce the impact of pandemics on mental health.

PUBLIC SIGNIFICANCE

Our findings suggest that the COVID-19 pandemic had negative impacts on people with eating disorders, including amplification of mental health symptoms and stressors around peak periods of infection and COVID-19 restrictions. These findings inform medical providers, policy-makers, and community-based supports about the information and resource needs of this group to ensure efficient dissemination in future public health emergencies and during the ongoing COVID-19 pandemic.

Plasma Concentrations of Short-Chain Fatty Acids in Active and Recovered Anorexia Nervosa

Anorexia nervosa (AN) is one of the most lethal psychiatric disorders. To date, we lack adequate knowledge about the (neuro)biological mechanisms of this disorder to inform evidence-based pharmacological treatment. Gut dysbiosis is a trending topic in mental health, including AN. Communication between the gut microbiota and the brain is partly mediated by metabolites produced by the gut microbiota such as short-chain fatty acids (SCFA). Previous research has suggested a role of SCFA in weight regulation (e.g., correlations between specific SCFA-producing bacteria and BMI have been demonstrated). Moreover, fecal SCFA concentrations are reported to be altered in active AN. However, data concerning SCFA concentrations in individuals who have recovered from AN are limited. In the present study, we analyzed and compared the plasma concentrations of seven SCFA (acetic-, butyric-, formic-, isobutyric-, isovaleric-, propionic-, and succinic acid) in females with active AN (n = 109), recovered from AN (AN-REC, n = 108), and healthy-weight age-matched controls (CTRL, n = 110), and explored correlations between SCFA concentrations and BMI. Significantly lower plasma concentrations of butyric, isobutyric-, and isovaleric acid were detected in AN as well as AN-REC compared with CTRL. We also show significant correlations between plasma concentrations of SCFA and BMI. These results encourage studies evaluating whether interventions directed toward altering gut microbiota and SCFA could support weight restoration in AN.

Mechanisms by which adverse childhood experiences, other traumas and PTSD influence the health and well-being of individuals with eating disorders throughout the life span

BACKGROUND

Multiple published sources from around the world have confirmed an association between an array of adverse childhood experiences (ACEs) and other traumatic events with eating disorders (EDs) and related adverse outcomes, including higher morbidity and mortality.

METHODS

In keeping with this Special Issue's goals, this narrative review focuses on the ACEs pyramid and its purported mechanisms through which child maltreatment and other forms of violence toward human beings influence the health and well-being of individuals who develop EDs throughout the life span. Relevant literature on posttraumatic stress disorder (PTSD) is highlighted when applicable.

RESULTS

At every level of the pyramid, it is shown that EDs interact with each of these proclaimed escalating mechanisms in a bidirectional manner that contributes to the predisposition, precipitation and perpetuation of EDs and related medical and psychiatric comorbidities, which then predispose to early death. The levels and their interactions that are discussed include the contribution of generational embodiment (genetics) and historical trauma (epigenetics), social conditions and local context, the ACEs and other traumas themselves, the resultant disrupted neurodevelopment, subsequent social, emotional and cognitive impairment, the adoption of health risk behaviors, and the development of disease, disability and social problems, all resulting in premature mortality by means of fatal complications and/or suicide.

CONCLUSIONS

The implications of these cascading, evolving, and intertwined perspectives have important implications for the assessment and treatment of EDs using trauma-informed care and trauma-focused integrated treatment approaches. This overview offers multiple opportunities at every level for the palliation and prevention of EDs and other associated trauma-related conditions, including PTSD.

Longitudinal experiences and impact of the COVID-19 pandemic among people with past or current eating disorders in Sweden

The study aimed to document the impact of the COVID-19 pandemic on the health and well-being of individuals with past and current eating disorders (ED) in Sweden. We re-contacted participants with a known lifetime history of ED from two previous Swedish studies. Participants completed an online survey about health and functioning at baseline early in the pandemic (Wave 1 ca May/June 2020; N= 982) and six months later (Wave 2 Dec/Jan 2020/21; N= 646). Three important patterns emerged: 1) higher current ED symptoms were associated with greater anxiety, worry, and pandemic-related ED symptom increase; 2) patterns were fairly stable across time, although a concerning percentage (23%) who were symptom-free at Wave 1 reported the re-emergence of symptoms at Wave 2; and 3) only a minority of participants (<50%) with a current ED were in treatment, and of those in treatment, many reported fewer treatment sessions and decreased quality of care. The COVID-19 pandemic appears to pose serious health challenges for individuals with an ED, whether currently symptomatic or in remission. We encourage health service providers and patient advocates to be alert to the needs of individuals with ED and to take active measures to ensure access to appropriate evidence-based care both during and following the pandemic.

Common Genetic Variation and Age of Onset of Anorexia Nervosa

Background

Genetics and biology may influence the age of onset of anorexia nervosa (AN). The aims of this study were to determine whether common genetic variation contributes to age of onset of AN and to investigate the genetic associations between age of onset of AN and age at menarche.

Methods

A secondary analysis of the Psychiatric Genomics Consortium genome-wide association study (GWAS) of AN was performed, which included 9335 cases and 31,981 screened controls, all from European ancestries. We conducted GWASs of age of onset, early-onset AN (<13 years), and typical-onset AN, and genetic correlation, genetic risk score, and Mendelian randomization analyses.

Results

Two loci were genome-wide significant in the typical-onset AN GWAS. Heritability estimates (single nucleotide polymorphism-h 2) were 0.01-0.04 for age of onset, 0.16-0.25 for early-onset AN, and 0.17-0.25 for typical-onset AN. Early- and typical-onset AN showed distinct genetic correlation patterns with putative risk factors for AN. Specifically, early-onset AN was significantly genetically correlated with younger age at menarche, and typical-onset AN was significantly negatively genetically correlated with anthropometric traits. Genetic risk scores for age of onset and early-onset AN estimated from independent GWASs significantly predicted age of onset. Mendelian randomization analysis suggested a causal link between younger age at menarche and early-onset AN.

Conclusions

Our results provide evidence consistent with a common variant genetic basis for age of onset and implicate biological pathways regulating menarche and reproduction.

Association of autism diagnosis and polygenic scores with eating disorder severity

Among individuals with eating disorders (ED), those with co-occurring autism are often considered to have more severe presentations and poorer prognosis. However, previous findings have been contradictory and limited by small sample size and/or cross-sectional assessment of autistic traits. We examine the hypothesis that autism diagnosis and autism polygenic score (PGS) are associated with increased ED severity in a large ED cohort using a broad range of ED severity indicators. Our cohort included 3189 individuals (64 males) born 1977-2000 with current or previous anorexia nervosa who participated in the Anorexia Nervosa Genetics Initiative-Sweden (ANGI-SE) and for whom genotypes and linkage to national registers were available. We identified 134 (4.2%) individuals with registered autism diagnoses. Individuals with confirmed autism diagnosis had significantly more severe ED across three sets of severity indicators. Some of the largest effects were found for the proportion of individuals who attempted suicide and who received tube feeding (higher in autism), and for the time spent in inpatient care (longer in autism). Results for autism PGS were not statistically significant. Adapting ED treatment to the needs of individuals with co-occurring autism is an important research direction to improve treatment outcome in this group.

Retention, engagement, and binge-eating outcomes: Evaluating feasibility of the Binge-Eating Genetics Initiative study

OBJECTIVE

Using preliminary data from the Binge-Eating Genetics Initiative (BEGIN), we evaluated the feasibility of delivering an eating disorder digital app, Recovery Record, through smartphone and wearable technology for individuals with binge-type eating disorders.

METHODS

Participants (n = 170; 96% female) between 18 and 45 years old with lived experience of binge-eating disorder or bulimia nervosa and current binge-eating episodes were recruited through the Recovery Record app. They were randomized into a Watch (first-generation Apple Watch + iPhone) or iPhone group; they engaged with the app over 30 days and completed baseline and endpoint surveys. Retention, engagement, and associations between severity of illness and engagement were evaluated.

RESULTS

Significantly more participants in the Watch group completed the study (p = .045); this group had greater engagement than the iPhone group (p's < .05; pseudo-R2 McFadden effect size = .01-.34). Overall, binge-eating episodes, reported for the previous 28 days, were significantly reduced from baseline (mean = 12.3) to endpoint (mean = 6.4): most participants in the Watch (60%) and iPhone (66%) groups reported reduced binge-eating episodes from baseline to endpoint. There were no significant group differences across measures of binge eating. In the Watch group, participants with fewer episodes of binge eating at baseline were more engaged (p's < .05; pseudo-R2 McFadden  = .01-.02). Engagement did not significantly predict binge eating at endpoint nor change in binge-eating episodes from baseline to endpoint for both the Watch and iPhone groups.

DISCUSSION

Using wearable technology alongside iPhones to deliver an eating disorder app may improve study completion and app engagement compared with using iPhones alone.

Genetics and neurobiology of eating disorders

Eating disorders (anorexia nervosa, bulimia nervosa and binge-eating disorder) are a heterogeneous class of complex illnesses marked by weight and appetite dysregulation coupled with distinctive behavioral and psychological features. Our understanding of their genetics and neurobiology is evolving thanks to global cooperation on genome-wide association studies, neuroimaging, and animal models. Until now, however, these approaches have advanced the field in parallel, with inadequate cross-talk. This review covers overlapping advances in these key domains and encourages greater integration of hypotheses and findings to create a more unified science of eating disorders. We highlight ongoing and future work designed to identify implicated biological pathways that will inform staging models based on biology as well as targeted prevention and tailored intervention, and will galvanize interest in the development of pharmacologic agents that target the core biology of the illnesses, for which we currently have few effective pharmacotherapeutics.

The BDNF Val66Met Polymorphism Does Not Increase Susceptibility to Activity-Based Anorexia in Rats

Simple Summary

Genetic animal models are a valuable tool for understanding how human pathologies develop. The type of animal model chosen is important for uncovering effects specific to certain behaviours and neurobiological functions. A polymorphism in the brain-derived neurotrophic factor (BDNF) has been linked with various clinical conditions in human subjects and with mouse models of anorectic behaviour. This study investigated for the first time the role of the BDNF Val66Met allelic substitution in a rat model of anorexia nervosa (AN), known as activity-based anorexia (ABA). Contrary to reports of altered BDNF signaling in patients with AN and increased anorectic behaviour in a mouse model containing the same allelic variation, it showed that 66Met did not alter susceptibility to weight loss or aspects of energy balance, including feeding and exercise in the rat model. It highlights the need to consider species–specific differences when evaluating animal models of human pathologies.

Abstract

Brain-derived neurotrophic factor (BDNF) is abundantly expressed in brain regions involved in both homeostatic and hedonic feeding, and it circulates at reduced levels in patients with anorexia nervosa (AN). A single nucleotide polymorphism in the gene encoding for BDNF (Val66Met) has been associated with worse outcomes in patients with AN, and it is shown to promote anorectic behaviour in a mouse model of caloric restriction paired with social isolation stress. Previous animal models of the Val66Met polymorphism have been in mice because of the greater ease in modification of the mouse genome, however, the most widely-accepted animal model of AN, known as activity-based anorexia (ABA), is most commonly conducted in rats. Here, we examine ABA outcomes in a novel rat model of the BDNF Val66Met allelic variation (Val68Met), and we investigate the role of this polymorphism in feeding, food choice and sucrose preference, and energy expenditure. We demonstrate that the BDNF Val68Met polymorphism does not influence susceptibility to ABA or any aspect of feeding behaviour. The discrepancy between these results and previous reports in mice may relate to species–specific differences in stress reactivity.

How genetic analysis may contribute to the understanding of avoidant/restrictive food intake disorder (ARFID)

Avoidant/restrictive food intake disorder (ARFID) was introduced in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). Unlike anorexia nervosa, ARFID is characterised by avoidant or restricted food intake that is not driven by weight or body shape-related concerns. As with other eating disorders, it is expected that ARFID will have a significant genetic risk component; however, sufficiently large-scale genetic investigations are yet to be performed in this group of patients. This narrative review considers the current literature on the diagnosis, presentation, and course of ARFID, including evidence for different presentations, and identifies fundamental questions about how ARFID might fit into the fluid landscape of other eating and mental disorders. In the absence of large ARFID GWAS, we consider genetic research on related conditions to point to possible features or mechanisms relevant to future ARFID investigations, and discuss the theoretical and clinical implications an ARFID GWAS. An argument for a collaborative approach to recruit ARFID participants for genome-wide association study is presented, as understanding the underlying genomic architecture of ARFID will be a key step in clarifying the biological mechanisms involved, and the development of interventions and treatments for this serious, and often debilitating disorder.

Intake and adherence to energy and nutrient recommendations among women and men with binge-type eating disorders and healthy controls

BACKGROUND & AIMS

Research quantifying dietary intake in individuals with bulimia nervosa and binge-eating disorder (i.e., binge-type eating disorders) is surprisingly scant. We assessed the dietary intake of women and men with binge-type eating disorders in a large case-control study and compared them with healthy controls. We also evaluated the extent to which their dietary intake adhered to the Nordic Nutrition Recommendations. Among cases, we assessed the relationship of binge eating frequency with energy and macronutrient intake.

METHODS

We derived the total daily energy, macro-, and micronutrient intake of 430 cases with binge-type eating disorders (women: n = 391, men: n = 39) and 1227 frequency-matched controls (women: n = 1,213, men: n = 14) who completed the MiniMeal-Q, a validated food frequency questionnaire. We calculated mean intake for men and women and, in women, compared mean intake of energy and nutrients between cases and controls using linear regression. We calculated the proportion of women and men who met the recommended intake levels from the NNR, and compared these proportions in female cases and controls using logistic regression. We used linear regression to examine energy and macronutrient intake of women with varying frequencies of current binge-eating.

RESULTS

Female, but not male cases, had a higher mean intake of total energy/day compared with controls and higher intake than recommended. The majority in all groups (male and female cases and controls) exceeded saturated fat recommendations, and did not meet recommendations for omega-3 fatty acid intake. Among all groups, adherence was low for vitamin D, selenium, and salt. Iron and folate intake was low among the majority of women, especially controls. Female cases with ≥4 binge-eating episodes in the past 28 days had higher intake of energy and percent carbohydrates, and lower intake of percent fat, compared to cases with no binge-eating episodes in the past month.

CONCLUSIONS

Higher than recommended total daily energy intake among women with binge-type eating disorders may lead to weight gain and downstream health complications, if persistent. In most women, iron and folate intake was insufficient, which may have negative consequences for reproductive health. We found suboptimal adherence for key nutrients that are important to limit (saturated fat and salt) or meet (omega-3 fatty acids) for cardiovascular and overall health in all groups. Nutrition counseling should form an important pillar of treatment to assist with normalization of eating patterns and may also benefit individuals without eating disorders to optimize nutrient intake for long term health promotion.

The Genetic Architecture of Obsessive-Compulsive Disorder: Contribution of Liability to OCD From Alleles Across the Frequency Spectrum

OBJECTIVE

Obsessive-compulsive disorder (OCD) is known to be substantially heritable; however, the contribution of genetic variation across the allele frequency spectrum to this heritability remains uncertain. The authors used two new homogeneous cohorts to estimate the heritability of OCD from inherited genetic variation and contrasted the results with those of previous studies.

METHODS

The sample consisted of 2,090 Swedish-born individuals diagnosed with OCD and 4,567 control subjects, all genotyped for common genetic variants, specifically >400,000 single-nucleotide polymorphisms (SNPs) with minor allele frequency (MAF) ≥0.01. Using genotypes of these SNPs to estimate distant familial relationships among individuals, the authors estimated the heritability of OCD, both overall and partitioned according to MAF bins.

RESULTS

Narrow-sense heritability of OCD was estimated at 29% (SE=4%). The estimate was robust, varying only modestly under different models. Contrary to an earlier study, however, SNPs with MAF between 0.01 and 0.05 accounted for 10% of heritability, and estimated heritability per MAF bin roughly followed expectations based on a simple model for SNP-based heritability.

CONCLUSIONS

These results indicate that common inherited risk variation (MAF ≥0.01) accounts for most of the heritable variation in OCD. SNPs with low MAF contribute meaningfully to the heritability of OCD, and the results are consistent with expectation under the "infinitesimal model" (also referred to as the "polygenic model"), where risk is influenced by a large number of loci across the genome and across MAF bins.

Polygenic association with severity and long-term outcome in eating disorder cases

About 20% of individuals with anorexia nervosa (AN) remain chronically ill. Therefore, early identification of poor outcome could improve care. Genetic research has identified regions of the genome associated with AN. Patients with anorexia nervosa were identified via the Swedish eating disorder quality registers Stepwise and Riksät and invited to participate in the Anorexia Nervosa Genetics Initiative. First, we associated genetic information longitudinally with eating disorder severity indexed by scores on the Clinical Impairment Assessment (CIA) in 2843 patients with lifetime AN with or without diagnostic migration to other forms of eating disorders followed for up to 16 years (mean = 5.3 years). Second, we indexed the development of a severe and enduring eating disorder (SEED) by a high CIA score plus a follow-up time ≥5 years. We associated individual polygenic scores (PGSs) indexing polygenic liability for AN, schizophrenia, and body mass index (BMI) with severity and SEED. After multiple testing correction, only the BMI PGS when calculated with traditional clumping and p value thresholding was robustly associated with disorder severity (β_PGS = 1.30; 95% CI: 0.72, 1.88; p = 1.2 × 10^-5) across all p value thresholds at which we generated the PGS. However, using the alternative PGS calculation method PRS-CS yielded inconsistent results for all PGS. The positive association stands in contrast to the negative genetic correlation between BMI and AN. Larger discovery GWASs to calculate PGS will increase power, and it is essential to increase sample sizes of the AN GWASs to generate clinically meaningful PGS as adjunct risk prediction variables. Nevertheless, this study provides the first evidence of potential clinical utility of PGSs for eating disorders.

Anorexia nervosa and inflammatory bowel diseases-Diagnostic and genetic associations

Background

Anorexia nervosa (AN), a serious eating disorder, and inflammatory bowel diseases (IBD) share a number of key symptoms, for example, discomfort during eating and early satiety. Despite the symptom overlap, studies on comorbidity are limited and mostly conducted in relatively small samples. This study investigates the comorbidity of diagnosed AN with IBD, and the subtypes Crohn's disease and ulcerative colitis, in a population-based sample and explores whether genetic factors could play a role in the overlap.

Methods

The study included 1,238,813 individuals born in Denmark 1981-2005 selected from the population register (5067 diagnosed with AN and 6947 diagnosed with any IBD), including a subsample of 23,236 individuals with genetic information (4271 with AN and 176 with any IBD). By combining hospital-based diagnoses recorded in health registers until 2013 with polygenic scores (PGS) of AN and IBD, we investigated possible associations between diagnoses of each disorder, both within individuals and families, and between PGS of one disorder and diagnosis of the other disorder. Analyses were conducted using Cox regression and logistic regression.

Results

We found that a prior diagnosis of AN was associated with hazard ratios of 1.44 (1.05, 1.97) for any IBD, 1.60 (1.04, 2.46) for Crohn's disease, and 1.66 (1.15, 2.39) for ulcerative colitis, whereas IBD diagnoses were not significantly associated with later AN diagnosis. No significant within-families associations were observed. We found no associations between AN and IBD using PGS.

Conclusions

AN was associated with later risk of IBD, Crohn's disease, and ulcerative colitis; however, the reverse was not observed. It is important for clinicians to be aware of this association to evaluate IBD as a differential diagnosis or an emergent condition in patients with AN.

Stressful life events among individuals with a history of eating disorders: a case-control comparison

BACKGROUND

Experiencing stressful life events (SLEs) can negatively impact mental health and increase risk for psychiatric disorders including eating disorders (EDs). Previous research has shown that childhood sexual abuse is associated with some EDs, but less is known about the association between other non-sexual SLEs and EDs.

METHOD

A case-control study of individuals with (n = 495, age mean ± SD = 29.1 ± 9.8 years) and without (n = 395, age = 30.2 ± 11.7) self-reported lifetime history of EDs was conducted to compare history of self-reported SLEs. Participants reported history of sexual (e.g., rape, other sexual assault) and non-sexual (e.g., emotional abuse, assault, bereavement) life events using an adaptation of the Stressful Life Events Screening Questionnaire. Individuals with EDs were divided into ED subtypes along the restricting - binge eating/purging spectrum to examine subtype differences. Logistic regressions were conducted for each SLE and ED subtype to obtain odds ratios (ORs). We report p-values corrected for multiple comparisons.

RESULTS

Exposure to any SLE was significantly more common in individuals with EDs than in controls (OR = 2.47, p < .001). Specifically, rape, other sexual assault, and emotional abuse were significantly more common among individuals with a history of binge-eating/purging ED subtypes (ORs = 2.15-3.58, p's < .01) compared with controls. Furthermore, history of life-threatening disease and loss of a close relative/partner/friend were associated with some ED subtypes. The association between SLEs and EDs was stronger for individuals who had experienced multiple SLEs.

CONCLUSION

By investigating a range of different SLEs, we showed that both sexual and non-sexual SLEs were more common in individuals with a history of EDs (binge-eating/purging subtypes) than controls. Results highlight the importance of assessing a variety of past SLEs in risk assessment for different EDs.

Serum profiling of anorexia nervosa: A 1H NMR-based metabolomics study

Our understanding of pathophysiological mechanisms underlying anorexia nervosa (AN) is incomplete. The aim was to conduct a metabolomics profiling of serum samples from women with AN (n = 65), women who have recovered from AN (AN-REC, n = 65), and age-matched healthy female controls (HC, n = 65). Serum concentrations of 21 metabolites were measured using proton nuclear magnetic resonance (¹H NMR). We used orthogonal partial least-squares discriminant analysis (OPLS-DA) modeling to assign group classification based on the metabolites. Analysis of variance (ANOVA) was used to test for metabolite concentration differences across groups. The OPLS-DA model could distinguish between the AN and HC groups (p = 9.05 × 10-11 R2Y = 0.36, Q2 = 0.37) and between the AN-REC and HC groups (p = 8.47 × 10-6, R2Y = 0.36, Q2 = 0.24,), but not between the AN and AN-REC groups (p = 0.63). Lower methanol concentration in the AN and AN-REC group explained most of the variance. Likewise, the strongest finding in the univariate analyses was lower serum methanol concentration in both AN and AN-REC compared with HC, which withstood adjustment for body mass index (BMI). We report for the first time lower serum concentrations of methanol in AN. The fact that low methanol was also found in recovered AN suggests that low serum concentration of methanol could either be trait marker or a scar effect of AN.