Screening, assessment and diagnosis in the eating disorders: findings from a rapid review

BACKGROUND

Limited screening practices, minimal eating disorder training in the healthcare professions, and barriers related to help-seeking contribute to persistent low rates of eating disorder detection, significant unmet treatment need, and appreciable associated disease burden. The current review sought to broadly summarise the literature and identify gaps relating to the screening, assessment, and diagnosis of eating disorders within Western healthcare systems.

METHODS

This paper forms part of a Rapid Review series scoping the evidence base for the field of eating disorders, conducted to inform the Australian National Eating Disorders Research and Translation Strategy 2021-2031, funded and released by the Australian Government. ScienceDirect, PubMed and Ovid/Medline were searched for studies published between 2009 and mid 2021 in English. High-level evidence such as meta-analyses, large population studies and Randomised Control Trials were prioritised through purposive sampling. Data from selected studies relating to Screening, Assessment and Diagnosis of eating disorders were synthesised and are disseminated in the current review.

RESULTS

Eighty seven studies were identified, 38% relating to screening and 62% to assessment and diagnosis. The majority of screening studies were conducted in university student samples, showing high prevalence but only modest improvements in help-seeking in those studies that followed up post-screen. In healthcare settings, clinicians continue to have difficulty identifying eating disorder presentations, particularly Binge Eating Disorder, Other Specified Feeding or Eating Disorders, and sub-threshold eating disorders. This is preceded by inadequate and frequently homogenous screening mechanisms and exacerbated by considerable personal and health-system barriers, including self-stigma and lack of resourcing. While all groups are at risk of delayed or no diagnosis, those at particular risk include LGBTQ+ and gender diverse individuals, individuals living in larger bodies, and males.

CONCLUSIONS

A majority of individuals with eating disorders remain undiagnosed and untreated despite a high prevalence of these conditions and increased advocacy in recent years. Research into improving detection and clinician diagnostic skill is extremely limited. Innovative empirical research is strongly recommended to address significant individual and health-system barriers currently preventing appropriate and timely intervention for many. Limited screening in healthcare settings and low rates of eating disorder training in the healthcare professions are just some of the barriers to help-seeking which may contribute to delayed intervention and diagnosis in the eating disorders. This has significant impacts, prolonging treatment when it is finally received, and increasing healthcare costs for both the individual and the healthcare system. The current review is part of a larger Rapid Review series conducted to inform the development of Australia's National Eating Disorders Research and Translation Strategy 2021-2031. A Rapid Review is designed to comprehensively summarise a body of literature in a short timeframe, often to guide policy-making and address urgent health concerns. The Rapid Review synthesises the current evidence-base and identifies gaps in eating disorder research and care, in order to guide decision making and address urgent health concerns. This paper gives a critical overview of the scientific literature relating to the current state of screening, assessment, and diagnosis of eating disorders within Western healthcare systems that may inform health policy and research in an Australian context. It covers screening initiatives in both general and high-risk populations; personal, clinician and healthcare system challenges relating to help-seeking; and obstacles to accurate and timely clinical diagnosis across the eating disorders.

Post-treatment haemolysis in African children with hyperparasitaemic falciparum malaria; a randomized comparison of artesunate and quinine

Background

Parenteral artesunate is the treatment of choice for severe malaria. Recently, haemolytic anaemia occurring 1 to 3 weeks after artesunate treatment of falciparum malaria has been reported in returning travellers in temperate countries.

Methods

To assess these potential safety concerns in African children, in whom most deaths from malaria occur, an open-labelled, randomized controlled trial was conducted in Kinshasa, Democratic Republic of Congo. 217 children aged between 6 months and 14 years with acute uncomplicated falciparum malaria and parasite densities over 100,000/μL were randomly allocated to intravenous artesunate or quinine, hospitalized for 3 days and then followed for 42 days.

Results

The immediate reduction in haemoglobin was less with artesunate than with quinine: median (IQR) fall at 72 h 1.4 g/dL (0.90–1.95) vs. 1.7 g/dL (1.10–2.40) (p = 0.009). This was explained by greater pitting then recirculation of once infected erythrocytes. Only 5% of patients (in both groups) had a ≥ 10% reduction in haemoglobin after day 7 (p = 0.1). One artesunate treated patient with suspected concomitant sepsis had a protracted clinical course and required a blood transfusion on day 14.

Conclusions

Clinically significant delayed haemolysis following parenteral artesunate is uncommon in African children hospitalised with acute falciparum malaria and high parasitaemias.

Trial registration

ClinicalTrials.gov; Identifier: NCT02092766 (18/03/2014)

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2678-0) contains supplementary material, which is available to authorized users.

A Toll-like receptor-1 variant and its characteristic cellular phenotype is associated with severe malaria in Papua New Guinean children

Genetic factors are likely to contribute to low severe malaria case fatality rates in Melanesian populations, but association studies can be underpowered and may not provide plausible mechanistic explanations if significant associations are detected. In preparation for a genome-wide association study, 29 candidate single-nucleotide polymorphisms (SNPs) with minor allele frequencies >5% were examined in a case-control study of 504 Papua New Guinean children with severe malaria. In parallel, an immunological substudy was performed on convalescent peripheral blood mononuclear cells (PBMCs) from cases and controls. Following stimulation with a Toll-like receptor (TLR) 1/2 agonist, effector cytokines and chemokines were assayed. The only significant genetic association observed involved a nonsynonymous SNP (TLR1rs4833095) in the TLR1 gene. A recessive (TT) genotype was associated with reduced odds of severe malaria of 0.52 (95% confidence interval (0.29-0.90), P=0.006). Concentrations of pro-inflammatory cytokines interleukin-1β and tumour necrosis factor α were significantly higher in severe malaria cases compared with healthy controls, but lower in children with the protective recessive (TT) genotype. A genetic variant in TLR1 may contribute to the low severe malaria case fatality rates in this region through a reduced pro-inflammatory cellular phenotype.

Fc gamma receptor IIa-H131R polymorphism and malaria susceptibility in sympatric ethnic groups, Fulani and Dogon of Mali

It has been previously shown that there are some interethnic differences in susceptibility to malaria between two sympatric ethnic groups of Mali, the Fulani and the Dogon. The lower susceptibility to Plasmodium falciparum malaria seen in the Fulani has not been fully explained by genetic polymorphisms previously known to be associated with malaria resistance, including haemoglobin S (HbS), haemoglobin C (HbC), alpha-thalassaemia and glucose-6-phosphate dehydrogenase (G6PD) deficiency. Given the observed differences in the distribution of FcγRIIa allotypes among different ethnic groups and with malaria susceptibility that have been reported, we analysed the rs1801274-R131H polymorphism in the FcγRIIa gene in a study of Dogon and Fulani in Mali (n = 939). We confirm that the Fulani have less parasite densities, less parasite prevalence, more spleen enlargement and higher levels of total IgG antibodies (anti-CSP, anti-AMA1, anti-MSP1 and anti-MSP2) and more total IgE (P < 0.05) compared with the Dogon ethnic group. Furthermore, the Fulani exhibit higher frequencies of the blood group O (56.5%) compared with the Dogon (43.5%) (P < 0.001). With regard to the FcγRIIa polymorphism and allele frequency, the Fulani group have a higher frequency of the H allele (Fulani 0.474, Dogon 0.341, P < 0.0001), which was associated with greater total IgE production (P = 0.004). Our findings show that the FcγRIIa polymorphism might have an implication in the relative protection seen in the Fulani tribe, with confirmatory studies required in other malaria endemic settings.

The 5q31 region in two African populations as a facet of natural selection by infectious diseases

Cases of extreme natural selection could lead either to rapid fixation or extinction of alleles depending on the population structure and size. It may also manifest in excess of heterozygosity and the locus concerned will be displaying such drastic features of allele change. We suspect the 5q31 in chromosome 5 to mirror situation of such extreme natural selection particularly that the region encompasses genes of type 2 cytokine known to associate with a number of infectious and non-infectious diseases. We typed two sets of single nucleotide polymorphisms (SNPS) in two populations: an initial limited set of only 4 SNP within the genes of IL-4, IL-13, IL-5 and IL-9 in 108 unrelated individuals and a replicating set of 14 SN P in 924 individuals from the same populations with disregard to relatedness. The results suggest the 5q31 area to be under intense selective pressure as indicated by marked heterozygosity independent of Linkage Disequilibrium (LD); difference in heterozygosity, allele, and haplotype frequencies between generations and departure from Hardy-Weinberg expectations (DHWE). The study area is endemic for several infectious diseases including malaria and visceral leishmaniasis (VL). Malaria caused by Plasmodiumfalciparum, however, occurs mostly with mild clinical symptoms in all ages, which makes it unlikely to account for these indices. The strong selection signals seems to emanate from recent outbreaks of VL which affected both populations to varying extent.

An investigation of transmission ratio distortion in the central region of the human MHC

Transmission ratio distortion (TRD) describes a significant departure from expected Mendelian inheritance ratios that is fundamental to both the biology of reproduction and statistical genetics. The relatively high fetal wastage in humans, with consequent selection of alleles in utero, makes it likely that TRD is prevalent in the human genome. The central region of the human major histocompatibility complex (MHC) is a strong TRD candidate, as it houses a number of immune and regulatory genes that may be important in pregnancy outcome. We used a nonhaplotype-based method to select 13 tagging SNPs from three central MHC candidate regions, and analysed their transmission in 380 newborns and their parents (1138 individuals). A TRD of 54:46 was noted in favour of the common allele of a promoter SNP in the CLIC1 gene (P = 0.025), with a similar distortion using haplotypes across the same gene region (P = 0.016). We also found evidence that markers in the CLIC1 gene region may have been subject to recent selection (P < 0.001). The study illustrates the potential benefits of screening for TRD and highlights the difficulties encountered therein.

Genetic association study for RSV bronchiolitis in infancy at the 5q31 cytokine cluster

BACKGROUND

The pathophysiological basis of severe respiratory syncytial virus (RSV) bronchiolitis in infancy is poorly understood and has hindered vaccine development. Studies implicate the cell-mediated immune response in the pathogenesis of the disease. A recent twin study estimated a heritable contribution of 22% to RSV bronchiolitis. Genetic epidemiology provides a new approach to identifying important immune determinants of disease severity.

METHODS

A comprehensive high-density gene-region association study for severe RSV bronchiolitis in infancy at 5q31 across 11 genes including the Th2-cytokine cluster was performed. A haplotype tagging approach was used to analyse genetic variation at 113 single nucleotide polymorphisms (SNPs) in 780 independent cases and 1045 controls. The study had sufficient power to detect small effects, perform extensive haplotype analysis and analyse both a principal phenotype and a refined age-limited phenotype enriched for first-exposure RSV infection.

RESULTS

SNP associations were found at IL4 and a highly significant risk haplotype was identified across IL13 CNS-1 and IL4 (odds ratio 1.69, p<0.0001), present in both case-control and family-based analyses. All associations were strongest for a phenotype limited to <6 months of age, implicating this locus in primary RSV disease. The same risk haplotype has previously been shown to be associated with increased IL13 expression.

CONCLUSIONS

A haplotype at IL13-1L4, which is associated with increased IL13 production, confers an increased risk of severe primary RSV bronchiolitis in early infancy. This study, together with previous studies implicating the same locus in atopic sensitisation, suggests that primary RSV bronchiolitis and atopy share a genetic contribution at the IL13-IL4 locus.

BCG-malaria co-Infection has paradoxical effects on C57BL/6 and A/J mouse strains

Bacillus Calmette-Guérin (BCG) infection of the spleen is a potent modifier of splenic function. Prior to malaria infection, we infected two mouse strains of differing susceptibility to Plasmodium chabaudi AS (C57BL/6 and A/J) with this mycobacterium. We then evaluated aspects of spleen cell composition, architecture and cytokine expression, and correlated these with the outcome. BCG preinfection resulted in protection of the A/J mice but paradoxically resulted in mortality of the C57BL/6 mice. The latter developed higher parasitaemias that peaked earlier than the A/J mice rendered resistant by BCG. BCG infection induced remarkable changes to splenic histology examined by H&E staining, but there were no consistent differences between mouse strains. C57BL/6 mice had higher absolute numbers of all immune cell phenotypes than did A/J mice, and higher macrophage and dendritic cell proportions. BCG-induced resistance in A/J mice was associated with an increased CD4+ expression of IFN-gamma whilst induced death in C57BL/6 mice was associated with excessive IFN-gamma expression. A moderate TH1 response in the A/J model may have been responsible for the improved survival, and an excessive TH1 response in the C57BL/6 model may have contributed to their death.

Haplotypic diversity in human CEACAM genes: effects on susceptibility to meningococcal disease

Adhesion between the opacity-associated adhesin (Opa) proteins of Neisseria meningitidis and human carcino-embryonic antigen cell adhesion molecule (CEACAM) proteins is an important stage in the pathogenesis of meningococcal disease, a globally important bacterial infection. Most disease is caused by a small number of meningococcal genotypes known as hyperinvasive lineages. As these are also carried asymptomatically, acquisition of them alone cannot explain why only some hosts develop meningococcal disease. Our aim was to determine whether genetic diversity in CEACAM is associated with susceptibility to meningococcal disease. Frequency distributions of alleles, genotypes and haplotypes were compared in four CEACAM genes in 384 case samples and 190 controls. Linkage disequilibrium among polymorphic sites, haplotype structures and relationships were also analysed. A number of polymorphisms were observed in CEACAM genes but the diversity of CEACAM1, to which most Opa proteins bind, was lower, and a small number of high-frequency haplotypes were detected. Dose-dependent associations of three CEACAM haplotypes with meningococcal disease were observed, with the effect of carrying these haplotypes amplified in homozygous individuals. Two haplotypes were protective while one haplotype in CEACAM6 was associated with a twofold increase in disease susceptibility. These data imply that human CEACAM may be one determinant of human susceptibility to meningococcal disease.

Genetic variation at the TNF locus and the risk of severe sequelae of ocular Chlamydia trachomatis infection in Gambians

Tumor necrosis factor (TNF) is thought to be a key mediator of the inflammatory and fibrotic response to Chlamydia trachomatis (Ct) infection. A large matched-pair case-control study investigated putative functional single nucleotide polymorphisms (SNPs) across the major histocompatibility complex (MHC) class III region, including TNF and its immediate neighbors nuclear factor of kappa light polypeptide gene enhancer in B cells (IkappaBL), inhibitor like 1 and lymphotoxin alpha (LTA) in relation to the risk of scarring sequelae of ocular Ct infection. Haplotype and linkage disequilibrium analysis demonstrated two haplotypes, differing at position TNF-308, conferring an increased risk of trichiasis. The TNF-308A allele, and its bearing haplotype, correlated with increased TNF production in lymphocyte cultures stimulated with chlamydial elementary body antigen. Thus TNF-308A may determine directly, or be a marker of a high TNF producer phenotype associated with increased risk of sequelae of chlamydial infection. Multivariate analysis provided evidence for the presence of additional risk-associated variants near the TNF locus.

A hallmark of balancing selection is present at the promoter region of interleukin 10

As an anti-inflammatory mediator IL10 is beneficial in certain contexts and deleterious in others. As increased production of IL10 favours protection against inflammatory disease, whereas low production promotes elimination of foreign pathogens by the host, we investigated the possible influence of balancing selection at this locus. We began by resequencing 48 European and 48 African chromosomes across 2.2 kb of the IL10 promoter region, and compared this with four neighbouring gene regions: MK2, IL19, IL20 and IL24. Analysis of nucleotide diversity showed a positive Tajima's D-test for IL10 in Europeans, of borderline statistical significance (1.89, P=0.05). Analysis of F(st) values showed significant population divergence at MK2, IL19, IL20 and IL24 (P<0.01) but not at IL10. Taken together, these findings are consistent with the hypothesis that balancing selection has played a role in the evolution of polymorphisms in the IL10 promoter region.

Population-specific patterns of linkage disequilibrium in the human 5q31 region

Linkage disequilibrium across the human genome is generally lower in West Africans than Europeans. However in the 5q31 region, which is rich in immune genes, we find significantly more examples of apparent nonrecombination between distant marker pairs in West Africans. Much of this effect is due to SNPs that are absent in Europeans, possibly reflecting recent positive selection in the West African population.

Analysis of IL10 haplotypic associations with severe malaria

We investigated the association between severe malaria and genetic variation of IL10 in Gambian children, as several lines of evidence indicate that IL10 is protective against severe malaria and that IL10 production is genetically determined. We began by identifying five informative SNPs in the Gambian population that were genotyped in a combined case-control and intrafamilial study including 654 cases of severe malaria, 579 sets of parents and 459 ethnically matched controls. No significant associations were identified with individual SNPs. One haplotype of frequency 0.11 was strongly associated with protection against severe malaria in the case-control analysis (odds ratio 0.52, P=0.00002), but the transmission disequilibrium test in families showed no significant effect. These findings raise the question of whether IL10 associations with severe malaria might be confounded by foetal survival rates or other sources of transmission bias.

Investigation of malaria susceptibility determinants in the IFNG/IL26/IL22 genomic region

Interferon-gamma, encoded by IFNG, is a key immunological mediator that is believed to play both a protective and a pathological role in malaria. Here, we investigate the relationship between IFNG variation and susceptibility to malaria. We began by analysing West African and European haplotype structure and patterns of linkage disequilibrium across a 100 kb genomic region encompassing IFNG and its immediate neighbours IL22 and IL26. A large case-control study of severe malaria in a West Africa population identified several weak associations with individual single-nucleotide polymorphisms in the IFNG and IL22 genes, and defined two IL22 haplotypes that are, respectively, associated with resistance and susceptibility. These data provide a starting point for functional and genetic analysis of the IFNG genomic region in malaria and other infectious and inflammatory conditions affecting African populations.

Risk of trachomatous scarring and trichiasis in Gambians varies with SNP haplotypes at the interferon-gamma and interleukin-10 loci

Experimental evidence implicates interferon gamma (IFNgamma) in protection from and resolution of chlamydial infection. Conversely, interleukin 10 (IL10) is associated with susceptibility and persistence of infection and pathology. We studied genetic variation within the IL10 and IFNgamma loci in relation to the risk of developing severe complications of human ocular Chlamydia trachomatis infection. A total of 651 Gambian subjects with scarring trachoma, of whom 307 also had potentially blinding trichiasis and pair-matched controls with normal eyelids, were screened for associations between single-nucleotide polymorphisms (SNPs), SNP haplotypes and the risk of disease. MassEXTEND (Sequenom) and MALDI-TOF mass spectrometry were used for detection and analysis of SNPs and the programs PHASE and SNPHAP used to infer haplotypes from population genetic data. Multivariate conditional logistic regression analysis identified IL10 and IFNgamma SNP haplotypes associated with increased risk of both trachomatous scarring and trichiasis. SNPs in putative IFNgamma and IL10 regulatory regions lay within the disease-associated haplotypes. The IFNgamma +874A allele, previously linked to lower IFNgamma production, lies in the IFNgamma risk haplotype and was more common among cases than controls, but not significantly so. The promoter IL10-1082G allele, previously associated with high IL10 expression, is in both susceptibility and resistance haplotypes.

The experience of shame in older psychiatric patients: a preliminary enquiry

Shame is a complex set of attitudes, feelings and behaviours that tend to motivate hiding and, if provoked, can lead to conflict with others. It is also related to the exercise of power within the relationship of care and therefore may be a relevant factor if older adults are forced to accept increased dependency. There are no systematic enquiries into shame processes and older psychiatric patients. The experience of trait and situational shame and psychopathology was explored with 50 older psychiatric patients, using a range of questionnaire measures. As predicted, trait shame correlated significantly with anxiety and depression scores. There was preliminary evidence to suggest that being in need of others may be shame-provoking for some patients and may have a bearing on why some patients fear dependency, conceal symptoms and have conflicted relationships with carers.

Increased in vivo transcription of an IL-8 haplotype associated with respiratory syncytial virus disease-susceptibility

Interleukin-8 (IL-8) has been implicated in the pathogenesis of RSV-induced bronchiolitis. Previously, we have described an association between bronchiolitis disease severity and a specific IL-8 haplotype comprising six single-nucleotide polymorphisms (SNPs) (-251A/+396G/+781T/+1238delA/+1633T/+2767T, haplotype 2). Here we investigated the functional basis for this association by measuring haplotype-specific transcription in vivo in human primary cells. We found a significant increase in transcript level derived from the IL-8 haplotype 2 relative to the mirror haplotype 1 (-251T/+396T/+781C/+1238insA/+1633C/+2767A) in respiratory epithelial cells but not in lymphocytes. A promoter polymorphism, -251A, present on the high producer haplotype, had no significant affect on the allele-specific level of transcription when analyzed in reporter gene experiments in human respiratory epithelial A549 cells. We proceeded to systematically screen for allele-specific protein-DNA binding in this functional haplotype, which revealed significant differential binding at the +781T/C polymorphism. C/EBP beta was identified as being part of a transcription factor binding complex that preferentially bound in the presence of the +781 T allele. These results suggest that the mechanism for disease susceptibility to RSV-induced bronchiolitis may occur through a haplotype-specific increase in IL-8 transcription, which may be mediated by functional polymorphisms within that haplotype.

Haplotypic relationship between SNP and microsatellite markers at the NOS2A locus in two populations

The density of genetic markers required for successful association mapping of complex diseases depends on linkage disequilibrium (LD) between non-functional markers and functional variants. The haplotypic relationship between stable markers and potentially unstable but highly informative markers (e.g. microsatellites) indicates that LD might be maintained over considerable genetic distance in non-African populations, supporting the use of such 'mixed marker haplotypes' in LD-based mapping, and allowing inferences to be drawn about human origins. We investigated sequence variation in the proximal 2.6 kb of the inducible nitric oxide synthase (NOS2A) promoter and the relationship between SNP haplotypes and a pentanucleotide microsatellite (the 'NOS2A(-2.6) microsatellite') in Gambians and UK Caucasians. UK Caucasians exhibited a subset of sequence diversity observed in Gambians, sharing four of 11 SNPs and a similar haplotypic structure. Five SNPs were found in the sequence of interspersed repetitive DNA elements. In both populations, there was dramatic loss of LD between SNP haplotypes and microsatellite alleles across a very short physical distance, suggesting a high intrinsic mutation rate of the NOS2A(-2.6) microsatellite, the SNP haplotypes are relatively ancient, or that this was a region of frequent recombination. Understanding locus- and population-specific LD is essential when designing and interpreting genetic association studies.