Adolescents with eating disorders during the COVID-19 pandemic: Changes in social ties and healthcare modalities. / Adolescentes con trastornos de la conducta alimentaria durante la pandemia por COVID-19: cambios en vínculos sociales y modalidades de atención.

Introduction. The COVID-19 pandemic has had a profound impact on the health of young people worldwide, especially on people with eating disorders (EDs) due to the stress, anxiety, and changes experienced in access to health care. Objective. To explore adolescents' perceptions on changes in their social ties and the modalities of health care for patients with EDs. Population and methods. Qualitative study using in-depth interviews with adolescents with EDs seen at a teaching hospital during the COVID-19 pandemic. Results. Fifteen adolescents were interviewed; their mean age was 18 years; 93% were girls. Anorexia nervosa was observed in 86.6%. The most relevant negative aspects perceived were discomfort with family life (80%) and dissatisfaction with social media content regarding body image and dieting (73%). The aspects perceived as positive were peer support (66%) and improvements in eating habits (66%). The main change identified regarding the management before the COVID-19 pandemic was online followup by the mental healthcare team (73%). Conclusion. The adolescent population with EDs during the mandatory social isolation period reported discomfort with family life and dissatisfaction with social media content regarding body image and dieting. Notwithstanding this, adolescents highlighted peer support and improvements in their eating habits as positive aspects.

Introducción. La pandemia por COVID-19 ha tenido un impacto profundo en la salud de la población joven de todo el mundo y especialmente en personas con trastornos de la conducta alimentaria (TCA) por situaciones de estrés, ansiedad y cambios en el acceso a la atención médica. Objetivo. Explorar las percepciones de adolescentes sobre los cambios en sus vínculos sociales y modalidades de atención en pacientes con TCA. Población y métodos. Se realizó un estudio cualitativo a través de entrevistas en profundidad a adolescentes con TCA en un hospital universitario durante la pandemia por COVID-19. Resultados. Se entrevistó a 15 adolescentes; el 93 % fueron mujeres y la mediana de edad fue 18 años. El 86,6 % tuvo anorexia nerviosa. Los aspectos negativos percibidos más importantes fueron los malestares en la convivencia familiar (80 %) y la disconformidad con los contenidos de las redes sociales sobre la imagen corporal y dietas (73 %). Los aspectos percibidos positivos fueron la ayuda de los pares (66 %) y mejoras en relación con la alimentación (66 %). El principal cambio identificado en comparación con el tratamiento recibido previo a la pandemia por COVID-19 fue el seguimiento virtual por salud mental (73 %). Conclusión. La población adolescente con TCA durante el ASPO manifestó malestar en la convivencia familiar y disconformidad en los contenidos en redes sociales sobre imagen corporal y dietas. Aunque resaltaron como aspectos positivos la ayuda de los pares y mejoras en su alimentación.

Ethylene produced in carpel primordia controls CmHB40 expression to inhibit stamen development.

Sex determination evolved to control the development of unisexual flowers. In agriculture, it conditions how plants are cultivated and bred. We investigated how female flowers develop in monoecious cucurbits. We discovered in melon, Cucumis melo, a mechanism in which ethylene produced in the carpel is perceived in the stamen primordia through spatially differentially expressed ethylene receptors. Subsequently, the CmEIN3/CmEIL1 ethylene signalling module, in stamen primordia, activates the expression of CmHB40, a transcription factor that downregulates genes required for stamen development and upregulates genes associated with organ senescence. Investigation of melon genetic biodiversity revealed a haplotype, originating in Africa, altered in EIN3/EIL1 binding to CmHB40 promoter and associated with bisexual flower development. In contrast to other bisexual mutants in cucurbits, CmHB40 mutations do not alter fruit shape. By disentangling fruit shape and sex-determination pathways, our work opens up new avenues in plant breeding.

CmLHP1 proteins play a key role in plant development and sex determination in melon (Cucumis melo).

In monoecious melon (Cucumis melo), sex is determined by the differential expression of sex determination genes (SDGs) and adoption of sex-specific transcriptional programs. Histone modifications such as H3K27me3 have been previously shown to be a hallmark associated to unisexual flower development in melon; yet, no genetic approaches have been conducted for elucidating the roles of H3K27me3 writers, readers, and erasers in this process. Here we show that melon homologs to Arabidopsis LHP1, CmLHP1A and B, redundantly control several aspects of plant development, including sex expression. Cmlhp1ab double mutants displayed an overall loss and redistribution of H3K27me3, leading to a deregulation of genes involved in hormone responses, plant architecture, and flower development. Consequently, double mutants display pleiotropic phenotypes and, interestingly, a general increase of the male:female ratio. We associated this phenomenon with a general deregulation of some hormonal response genes and a local activation of male-promoting SDGs and MADS-box transcription factors. Altogether, these results reveal a novel function for CmLHP1 proteins in maintenance of monoecy and provide novel insights into the polycomb-mediated epigenomic regulation of sex lability in plants.

Evolución y tratamiento de los trastornos de la conducta alimentaria en adolescentes: serie de casos / Treatment of eating disorders in adolescents: case series

Los trastornos de la conducta alimentaria son enfermedades de elevada prevalencia en la adolescencia y tienen repercusión en la salud integral. El objetivo fue describir su evolución y tratamiento en un grupo de adolescentes. Se estudiaron adolescentes menores de 18 años con al menos 6 meses de seguimiento y tratados por un equipo interdisciplinario. Se incluyeron 41 adolescentes: 23 presentaron anorexia nerviosa; 9, trastornos alimentarios no especificados; 7, bulimia nerviosa y 2, trastorno por atracones. El 35 % de pacientes con anorexia nerviosa requirió internación por complicaciones de la desnutrición. El 69 % de las pacientes con anorexia nerviosa, el 57 % de quienes tenían bulimia nerviosa y el 78 % de quienes tenían un trastorno alimentario no especificado presentaron remisión total o parcial, y no hubo pacientes fallecidos. La mayoría presentó una evolución favorable con el tratamiento.

Eating disorders are highly prevalent diseases in adolescence and have an impact on overall health. The objective was to describe the evolution and treatment of eating disorders in adolescents. Adolescents under 18 years of age with at least 6 months of follow-up and treated by an interdisciplinary team were studied. Forty one adolescents were included, 23 presented anorexia nervosa, 9 unspecified eating disorders, 7 bulimia nervosa and 2 binge eating disorders. Thirty five percent of patients with anorexia nervosa required hospitalization for complications of malnutrition. Sixty nine percent of the patients with anorexia nervosa, 57 % with bulimia nervosa, and 78 % with unspecified eating disorders had total or partial remission and there were no deceased patients. The majority presented a favorable evolution with the treatment.

[Treatment of eating disorders in adolescents: case series]. / Evolución y tratamiento de los trastornos de la conducta alimentaria en adolescentes: serie de casos.

Eating disorders are highly prevalent diseases in adolescence and have an impact on overall health. The objective was to describe the evolution and treatment of eating disorders in adolescents. Adolescents under 18 years of age with at least 6 months of follow-up and treated by an interdisciplinary team were studied. Forty one adolescents were included, 23 presented anorexia nervosa, 9 unspecified eating disorders, 7 bulimia nervosa and 2 binge eating disorders. Thirty five percent of patients with anorexia nervosa required hospitalization for complications of malnutrition. Sixty nine percent of the patients with anorexia nervosa, 57 % with bulimia nervosa, and 78 % with unspecified eating disorders had total or partial remission and there were no deceased patients. The majority presented a favorable evolution with the treatment.

Los trastornos de la conducta alimentaria son enfermedades de elevada prevalencia en la adolescencia y tienen repercusión en la salud integral. El objetivo fue describir su evolución y tratamiento en un grupo de adolescentes. Se estudiaron adolescentes menores de 18 años con al menos 6 meses de seguimiento y tratados por un equipo interdisciplinario. Se incluyeron 41 adolescentes: 23 presentaron anorexia nerviosa; 9, trastornos alimentarios no especificados; 7, bulimia nerviosa y 2, trastorno por atracones. El 35 % de pacientes con anorexia nerviosa requirió internación por complicaciones de la desnutrición. El 69 % de las pacientes con anorexia nerviosa, el 57 % de quienes tenían bulimia nerviosa y el 78 % de quienes tenían un trastorno alimentario no especificado presentaron remisión total o parcial, y no hubo pacientes fallecidos. La mayoría presentó una evolución favorable con el tratamiento.

Polycomb-dependent differential chromatin compartmentalization determines gene coregulation in Arabidopsis.

In animals, distant H3K27me3-marked Polycomb targets can establish physical interactions forming repressive chromatin hubs. In plants, growing evidence suggests that H3K27me3 acts directly or indirectly to regulate chromatin interactions, although how this histone modification modulates 3D chromatin architecture remains elusive. To decipher the impact of the dynamic deposition of H3K27me3 on the Arabidopsis thaliana nuclear interactome, we combined genetics, transcriptomics, and several 3D epigenomic approaches. By analyzing mutants defective for histone H3K27 methylation or demethylation, we uncovered the crucial role of this chromatin mark in short- and previously unnoticed long-range chromatin loop formation. We found that a reduction in H3K27me3 levels led to a decrease in the interactions within Polycomb-associated repressive domains. Regions with lower H3K27me3 levels in the H3K27 methyltransferase clf mutant established new interactions with regions marked with H3K9ac, a histone modification associated with active transcription, indicating that a reduction in H3K27me3 levels induces a global reconfiguration of chromatin architecture. Altogether, our results reveal that the 3D genome organization is tightly linked to reversible histone modifications that govern chromatin interactions. Consequently, nuclear organization dynamics shapes the transcriptional reprogramming during plant development and places H3K27me3 as a key feature in the coregulation of distant genes.

The matrix revolutions: towards the decoding of the plant chromatin three-dimensional reality.

In recent years, we have witnessed a significant increase in studies addressing the three-dimensional (3D) chromatin organization of the plant nucleus. Important advances in chromatin conformation capture (3C)-derived and related techniques have allowed the exploration of the nuclear topology of plants with large and complex genomes, including various crops. In addition, the increase in their resolution has permitted the depiction of chromatin compartmentalization and interactions at the gene scale. These studies have revealed the highly complex mechanisms governing plant nuclear architecture and the remarkable knowledge gaps in this field. Here we discuss the state-of-the-art in plant chromosome architecture, including our knowledge of the hierarchical organization of the genome in 3D space and regarding other nuclear components. Furthermore, we highlight the existence in plants of topologically associated domain (TAD)-like structures that display striking differences from their mammalian counterparts, proposing the concept of ICONS-intergenic condensed spacers. Similarly, we explore recent advances in the study of chromatin loops and R-loops, and their implication in the regulation of gene activity. Finally, we address the impact that polyploidization has had on the chromatin topology of modern crops, and how this is related to phenomena such as subgenome dominance and biased gene retention in these organisms.

GCN5 modulates salicylic acid homeostasis by regulating H3K14ac levels at the 5' and 3' ends of its target genes.

The modification of histones by acetyl groups has a key role in the regulation of chromatin structure and transcription. The Arabidopsis thaliana histone acetyltransferase GCN5 regulates histone modifications as part of the Spt-Ada-Gcn5 Acetyltransferase (SAGA) transcriptional coactivator complex. GCN5 was previously shown to acetylate lysine 14 of histone 3 (H3K14ac) in the promoter regions of its target genes even though GCN5 binding did not systematically correlate with gene activation. Here, we explored the mechanism through which GCN5 controls transcription. First, we fine-mapped its GCN5 binding sites genome-wide and then used several global methodologies (ATAC-seq, ChIP-seq and RNA-seq) to assess the effect of GCN5 loss-of-function on the expression and epigenetic regulation of its target genes. These analyses provided evidence that GCN5 has a dual role in the regulation of H3K14ac levels in their 5' and 3' ends of its target genes. While the gcn5 mutation led to a genome-wide decrease of H3K14ac in the 5' end of the GCN5 down-regulated targets, it also led to an increase of H3K14ac in the 3' ends of GCN5 up-regulated targets. Furthermore, genome-wide changes in H3K14ac levels in the gcn5 mutant correlated with changes in H3K9ac at both 5' and 3' ends, providing evidence for a molecular link between the depositions of these two histone modifications. To understand the biological relevance of these regulations, we showed that GCN5 participates in the responses to biotic stress by repressing salicylic acid (SA) accumulation and SA-mediated immunity, highlighting the role of this protein in the regulation of the crosstalk between diverse developmental and stress-responsive physiological programs. Hence, our results demonstrate that GCN5, through the modulation of H3K14ac levels on its targets, controls the balance between biotic and abiotic stress responses and is a master regulator of plant-environmental interactions.

Wheat chromatin architecture is organized in genome territories and transcription factories.

BACKGROUND: Polyploidy is ubiquitous in eukaryotic plant and fungal lineages, and it leads to the co-existence of several copies of similar or related genomes in one nucleus. In plants, polyploidy is considered a major factor in successful domestication. However, polyploidy challenges chromosome folding architecture in the nucleus to establish functional structures. RESULTS: We examine the hexaploid wheat nuclear architecture by integrating RNA-seq, ChIP-seq, ATAC-seq, Hi-C, and Hi-ChIP data. Our results highlight the presence of three levels of large-scale spatial organization: the arrangement into genome territories, the diametrical separation between facultative and constitutive heterochromatin, and the organization of RNA polymerase II around transcription factories. We demonstrate the micro-compartmentalization of transcriptionally active genes determined by physical interactions between genes with specific euchromatic histone modifications. Both intra- and interchromosomal RNA polymerase-associated contacts involve multiple genes displaying similar expression levels. CONCLUSIONS: Our results provide new insights into the physical chromosome organization of a polyploid genome, as well as on the relationship between epigenetic marks and chromosome conformation to determine a 3D spatial organization of gene expression, a key factor governing gene transcription in polyploids.

The Polycomb protein LHP1 regulates Arabidopsis thaliana stress responses through the repression of the MYC2-dependent branch of immunity.

Polycomb repressive complexes (PRCs) have been traditionally associated with the regulation of developmental processes in various organisms, including higher plants. However, similar to other epigenetic regulators, there is accumulating evidence for their role in the regulation of stress and immune-related pathways. In the current study we show that the PRC1 protein LHP1 is required for the repression of the MYC2 branch of jasmonic acid (JA)/ethylene (ET) pathway of immunity. Loss of LHP1 induces the reduction in H3K27me3 levels in the gene bodies of ANAC019 and ANAC055, as well as some of their targets, leading to their transcriptional upregulation. Consistently, increased expression of these two transcription factors leads to the misregulation of several of their genomic targets. The lhp1 mutant mimics the MYC2, ANAC019, and ANAC055 overexpressers in several of their phenotypes, including increased aphid resistance, abscisic acid (ABA) sensitivity and drought tolerance. In addition, like the MYC2 and ANAC overexpressers, lhp1 displays reduced salicylic acid (SA) content caused by a deregulation of ICS1 and BSMT1, as well as increased susceptibility to the hemibiotrophic pathogen Pseudomonas syringae pv. tomato DC3000. Together, our results indicate that LHP1 regulates the expression of stress-responsive genes as well as the homeostasis and responses to the stress hormones SA and ABA. This protein emerges as a key chromatin player fine tuning the complex balance between developmental and stress-responsive processes.

The quest for epigenetic regulation underlying unisexual flower development in Cucumis melo.

BACKGROUND: Melon (Cucumis melo) is an important vegetable crop from the Cucurbitaceae family and a reference model specie for sex determination, fruit ripening and vascular fluxes studies. Nevertheless, the nature and role of its epigenome in gene expression regulation and more specifically in sex determination remains largely unknown. RESULTS: We have investigated genome wide H3K27me3 and H3K9ac histone modifications and gene expression dynamics, in five melon organs. H3K9ac and H3K27me3 were mainly distributed along gene-rich regions and constrained to gene bodies. H3K9ac was preferentially located at the TSS, whereas H3K27me3 distributed uniformly from TSS to TES. As observed in other species, H3K9ac and H3K27me3 correlated with high and low gene expression levels, respectively. Comparative analyses of unisexual flowers pointed out sex-specific epigenetic states of TFs involved in ethylene response and flower development. Chip-qPCR analysis of laser dissected carpel and stamina primordia, revealed sex-specific histone modification of MADS-box genes. Using sex transition mutants, we demonstrated that the female promoting gene, CmACS11, represses the expression of the male promoting gene CmWIP1 via deposition of H3K27me3. CONCLUSIONS: Our findings reveal the organ-specific landscapes of H3K9ac and H3K27me3 in melon. Our results also provide evidence that the sex determination genes recruit histone modifiers to orchestrate unisexual flower development in monoecious species.

Chromatin architecture: A new dimension in the dynamic control of gene expression.

As the most recent evidence of eukaryotic cell complexity, genome architecture has astounded the scientific community and prompted a variety of technical and cognitive challenges. Several technologies have emerged and evidenced the integration of chromatin packaging and topology, epigenetic processes, and transcription for the pertinent regulation of gene expression. In the present addendum we present and discuss some of our recent research, directed toward the holistic comprehension of the processes by which plants respond to environmental and developmental stimuli. We propose that the study of genome topology and genomic interactions is essential for the understanding of the molecular mechanisms behind a phenotype. Even though our knowledge and understanding of genome architecture and hierarchy has improved substantially in the last few years -in Arabidopsis and other eukaryotes -, there is still a long way ahead in this relatively new field of study. For this, it is necessary to take advantage of the high resolution of the emerging available techniques, and perform integrative approaches with which it will be possible to depict the role of chromatin architecture in the regulation of transcription and ultimately, physiological processes.

Put your 3D glasses on: plant chromatin is on show.

The three-dimensional organization of the eukaryotic nucleus and its chromosomal conformation have emerged as important features in the complex network of mechanisms behind gene activity and genome connectivity dynamics, which can be evidenced in the regionalized chromosomal spatial distribution and the clustering of diverse genomic regions with similar expression patterns. The development of chromatin conformation capture (3C) techniques has permitted the elucidation of commonalities between the eukaryotic phyla, as well as important differences among them. The growing number of studies in the field performed in plants has shed light on the structural and regulatory features of these organisms. For instance, it has been proposed that plant chromatin can be arranged into different conformations such as Rabl, Rosette-like, and Bouquet, and that both short- and long-range chromatin interactions occur in Arabidopsis. In this review, we compile the current knowledge about chromosome architecture characteristics in plants, as well as the molecular events and elements (including long non-coding RNAs, histone and DNA modifications, chromatin remodeling complexes, and transcription factors) shaping the genome three-dimensional conformation. Furthermore, we discuss the developmental outputs of genome topology-mediated gene expression regulation. It is becoming increasingly clear that new tools and techniques with higher resolution need to be developed and implemented in Arabidopsis and other model plants in order to better understand chromosome architecture dynamics, from an integrative perspective with other fields of plant biology such as development, stress biology, and finally agriculture.

Promoting resilience in adults with experience of intimate partner violence or child maltreatment: a narrative synthesis of evidence across settings.

BACKGROUND: People who have experienced intimate partner violence (IPV) or child maltreatment (CM) are at risk of having lower resilience and adverse psychological outcomes. In keeping with the social and environmental factors that support resilience, there is a need to take a public health approach to its investigation and to identify existing initiatives in particular settings and populations that can guide its deliberate promotion. METHOD: This narrative synthesis examines quantitative and qualitative studies of interventions with resilience-related outcomes in specified health and other settings. Clinical RCTs are excluded as beyond the scope of this review. RESULTS: Twenty studies were identified for review in several settings, consisting of 14 quantitative studies, 2 review studies, 2 qualitative studies and 2 mixed-methods studies. Three quantitative studies produced strong evidence to support: a home visitation program for at-risk mothers; a methadone program for women and a substance abuse program. This review reveals that few studies use specific resilience measures. CONCLUSIONS: The topic has been little studied despite high needs for public health interventions in countries of all types. Interventions and research studies that use specific resilience measures are likely to help measure and integrate what is currently a disparate area. IMPLICATIONS: The participation of people with IPV or CM history in program and research design and implementation is indicated to support advocacy, innovation and sustainable interventions. This is especially pertinent for interventions in LAMIC and indigenous settings where continuing programs are sorely needed.

Structural and functional basis for starch binding in the SnRK1 subunits AKINß2 and AKINßγ.

Specialized carbohydrate-binding domains, the Starch-Binding Domain (SBD) and the Glycogen Binding Domain (GBD), are motifs of approximately 100 amino acids directly or indirectly associated with starch or glycogen metabolism. Members of the regulatory ß subunit of the heterotrimeric complex AMPK/SNF1/SnRK1 contain an SBD or GBD. In Arabidopsis thaliana, the ß regulatory subunit AKINß2 and a γ-type subunit, AKINßγ, also have an SBD. In this work, we compared the SBD of AKINß2 and AKINßγ with the GBD present in rat AMPKß1 and demonstrated that they conserved the same overall topology. The majority of the amino acids identified in the protein-carbohydrate interactions in the rat AMPKß1 are conserved in the two plant proteins. In AKINßγ, there is an insertion of three amino acids that creates a loop adjacent to one of the conserved tryptophan residues. Functionally, the SBD from AKINßγ and AKINß2 could bind starch, but there was an important difference in the association when an amylose/amylopectin (A/A) mixture was used. The physiological relevance of binding to starch was clear for AKINßγ, because immunolocalization experiments identified this protein inside the chloroplast. SnRK1 activity was not affected by the addition of A/A to the reaction mixture. However, addition of starch inhibited the activity 85%. Furthermore, proteins associated with A/A and starch in an in vitro-binding assay accounted for 10-20% of total SnRK1 kinase activity. Interestingly, the identification of the SnRK1 subunits associated to the protein-carbohydrate complex indicated that only the catalytic subunits, AKIN10 and AKIN11, and the regulatory subunit AKINßγ were present. These results suggest that a dimer formed between either catalytic subunit and AKINßγ could be associated with the A/A mixture in its active form but the same subunits are inactivated when binding to starch.

Cognitive behavioral therapy age effects in child and adolescent anxiety: an individual patient data metaanalysis.

BACKGROUND: Investigations of age effects on youth anxiety outcomes in randomized trials (RCTs) of cognitive behavior therapy (CBT) have failed to yield a clear result due to inadequate statistical power and methodologic weaknesses. We conducted an individual patient data metaanalysis to address this gap. QUESTION: Does age moderate CBT effect size, measured by a clinically and statistically significant interaction between age and CBT exposure? METHODS: All English language RCTs of CBT for anxiety in 6-19 year olds were identified using systematic review methods. Investigators of eligible trials were invited to submit their individual patient data. The anxiety disorder interview schedule (ADIS) primary diagnosis severity score was the primary outcome. Age effects were investigated using multilevel modeling to account for study level data clustering and random effects. RESULTS: Data from 17 of 23 eligible trials were obtained (74%); 16 studies and 1,171 (78%) cases were available for the analysis. No interaction between age and CBT exposure was found in a model containing age, sex, ADIS baseline severity score, and comorbid depression diagnosis (power ≥ 80%). Sensitivity analyses, including modeling age as both a categorical and continuous variable, revealed this result was robust. CONCLUSIONS: Adolescents who receive CBT in efficacy research studies show benefits comparable to younger children. However, CBT protocol modifications routinely carried out by expert trial therapists may explain these findings. Adolescent CBT protocols are needed to facilitate the transportability of efficacy research effects to usual care settings where therapists may have less opportunity for CBT training and expertise development.

Randomized trials published in higher vs. lower impact journals differ in design, conduct, and analysis.

OBJECTIVE: To compare methodological characteristics of randomized controlled trials (RCTs) published in higher vs. lower impact Core Clinical Journals. STUDY DESIGN AND SETTING: We searched MEDLINE for RCTs published in 2007 in Core Clinical Journals. We randomly sampled 1,140 study reports in a 1:1 ratio in higher (five general medicine journals with the highest total citations in 2007) and lower impact journals. RESULTS: Four hundred sixty-nine RCTs proved eligible: 219 in higher and 250 in lower impact journals. RCTs in higher vs. lower impact journals had larger sample sizes (median, 285 vs. 39), were more likely to receive industry funding (53% vs. 28%), declare concealment of allocation (66% vs. 36%), declare blinding of health care providers (53% vs. 41%) and outcome adjudicators (72% vs. 54%), report a patient-important primary outcome (69% vs. 50%), report subgroup analyses (64% vs. 26%), prespecify subgroup hypotheses (42% vs. 20%), and report a test for interaction (54% vs. 27%); P < 0.05 for all differences. CONCLUSION: RCTs published in higher impact journals were more likely to report methodological safeguards against bias and patient-important outcomes than those published in lower impact journals. However, sufficient limitations remain such that publication in a higher impact journal does not ensure low risk of bias.

Credibility of claims of subgroup effects in randomised controlled trials: systematic review.

OBJECTIVE: To investigate the credibility of authors' claims of subgroup effects using a representative sample of recently published randomised controlled trials. DESIGN: Systematic review. DATA SOURCE: Core clinical journals, as defined by the National Library of Medicine, in Medline. STUDY SELECTION: Randomised controlled trials published in 2007. Using prespecified criteria, teams of trained reviewers independently judged whether authors claimed subgroup effects and the strength of their claims. Reviewers assessed each of these claims against 10 predefined criteria, developed through a search of existing criteria and a consensus process. RESULTS: Of 207 randomised controlled trials reporting subgroup analyses, 64 (31%) made claims for the primary outcome. Of those, 20 were strong claims and 28 claims of a likely effect. Authors included subgroup variables measured at baseline in 60 (94%) trials, used subgroup variable as a stratification factor at randomisation in 13 (20%), clearly prespecified their hypotheses in 26 (41%), correctly prespecified direction in 4 (6%), tested a small number of hypotheses in 28 (44%), carried out a test of interaction that proved statistically significant in 6 (9%), documented replication of a subgroup effect with previous related studies in 21 (33%), identified consistency of a subgroup effect across related outcomes in 19 (30%), and provided a compelling indirect evidence for the effect in 14 (22%). In the 19 trials making more than one claim, only one (5%) checked the independence of the interaction. Of the 64 claims, 54 (84%) met four or fewer of the 10 criteria. For strong claims, more than 50% failed each of the individual criteria, and only three (15%) met more than five criteria. CONCLUSION: Authors often claim subgroup effects in their trial report. However, the credibility of subgroup effects, even when claims are strong, is usually low. Users of the information should treat claims that fail to meet most criteria with scepticism. Trial researchers should report the conduct of subgroup analyses and provide sufficient evidence when claiming a subgroup effect or suggesting a possible effect.