Does hypoleptinemia trigger entrapment in anorexia nervosa? Etiological and clinical considerations

Based on the recent observation that human recombinant leptin (r-Met-hu-leptin; metreleptin) may induce a profound alleviation of the complex symptomatology of patients with anorexia nervosa (AN), we examine the implications for our conceptualisation of this eating disorder. Hypoleptinemia as a core endocrine feature of AN serves as a central and peripheral trigger of tissue-specific adaptations to starvation. In this narrative review, we argue that leptin deficiency may explain many of the puzzling features of this eating disorder. Weight loss can be viewed as a two-step process, with only the second step entailing hypoleptinemia and thereby the entrapment characteristic of AN. We discuss the central and peripheral distribution of leptin receptors and consider possible functional implications of hypoleptinemia. We contrast the slow psychological recovery of patients with AN and of people who experienced starvation upon weight recovery with the rapid onset of improvements upon off-label metreleptin treatment. Characteristics of the sex and age dependent secretion of leptin may contribute to the elevated vulnerability of young females to develop AN.

Differentiating anorexia nervosa and atypical anorexia nervosa with absolute weight cut-offs results in a skewed distribution for premorbid weight among youth

OBJECTIVE

Anorexia nervosa (AN) and atypical AN are conceptualized as distinct illnesses, despite similar characteristics and sequelae. Whereas DSM-5 differentiates youth with AN and atypical AN by the presence of clinical 'underweight' (i.e., 5th BMI percentile for age-and-sex (BMI%)), we hypothesized that using this weight cut-off to discern diagnoses creates a skewed distribution for premorbid weight.

METHOD

Participants included hospitalized youth with AN (n = 165, 43.1%) and atypical AN (n = 218, 56.9%). Frequency analyses and chi-square tests assessed the distribution of premorbid BMI z-scores (BMIz) for diagnosis. Non-parametric Spearman correlations and Stepwise Linear regressions examined relationships between premorbid BMIz, admission BMIz, and weight loss in kg.

RESULTS

Premorbid BMIz distributions differed significantly for diagnosis (p < .001), with an underrepresentation of 'overweight/obesity' (i.e., BMI% ≥ 85th) in AN. Despite commensurate weight loss in AN and atypical AN, patients with premorbid 'overweight/obesity' were 8.31 times more likely to have atypical AN than patients with premorbid BMI% < 85th. Premorbid BMIz explained 57% and 39% of the variance in admission BMIz and weight loss, respectively.

DISCUSSION

Findings support a homogenous model of AN and atypical AN, with weight loss predicted by premorbid BMI in both illnesses. Accordingly, premorbid BMI and weight loss (versus presenting BMI) may better denote the presence of an AN-like phenotype across the weight spectrum. Findings also suggest that differentiating diagnoses with BMI% < 5th requires that youth with higher BMIs lose disproportionately more weight for an AN diagnosis. This is problematic given unique treatment barriers experienced in atypical AN.

PUBLIC SIGNIFICANCE

Anorexia nervosa (AN) and atypical AN are considered distinct conditions in youth, with differential diagnosis hinging upon a presenting weight status of 'underweight' (i.e., BMI percentile for age-and-sex (BMI%) < 5th). In our study, youth with premorbid 'overweight/obesity' (BMI% ≥ 85th) disproportionately remained above this threshold, despite similar weight loss. Coupled with prior evidence for commensurate characteristics and sequelae in both diagnoses, we propose that DSM-5 differentiation of AN and atypical AN inadvertently reinforces weight stigma and may contribute to treatment disparities in atypical AN.

Premorbid body weight predicts weight loss in both anorexia nervosa and atypical anorexia nervosa: Further support for a single underlying disorder

OBJECTIVE

For adolescents, DSM-5 differentiates anorexia nervosa (AN) and atypical AN with the 5th BMI-centile-for-age. We hypothesized that the diagnostic weight cut-off yields (i) lower weight loss in atypical AN and (ii) discrepant premorbid BMI distributions between the two disorders. Prior studies demonstrate that premorbid BMI predicts admission BMI and weight loss in patients with AN. We explore these relationships in atypical AN.

METHOD

Based on admission BMI-centile < or ≥5th, participants included 411 female adolescent inpatients with AN and 49 with atypical AN from our registry study. Regression analysis and t-tests statistically addressed our hypotheses and exploratory correlation analyses compared interrelationships between weight loss, admission BMI, and premorbid BMI in both disorders.

RESULTS

Weight loss in atypical AN was 5.6 kg lower than in AN upon adjustment for admission age, admission height, premorbid weight and duration of illness. Premorbid BMI-standard deviation scores differed by almost one between both disorders. Premorbid BMI and weight loss were strongly correlated in both AN and atypical AN.

DISCUSSION

Whereas the weight cut-off induces discrepancies in premorbid weight and adjusted weight loss, AN and atypical AN overall share strong weight-specific interrelationships that merit etiological consideration. Epidemiological and genetic associations between AN and low body weight may reflect a skewed premorbid BMI distribution. In combination with prior findings for similar psychological and medical characteristics in AN and atypical AN, our findings support a homogenous illness conceptualization. We propose that diagnostic subcategorization based on premorbid BMI, rather than admission BMI, may improve clinical validity.

PUBLIC SIGNIFICANCE

Because body weights of patients with AN must drop below the 5th BMI-centile per DSM-5, they will inherently require greater weight loss than their counterparts with atypical AN of the same sex, age, height and premorbid weight. Indeed, patients with atypical AN had a 5.6 kg lower weight loss after controlling for these variables. In comparison to the reference population, we found a lower and higher mean premorbid weight in patients with AN and atypical AN, respectively. Considering previous psychological and medical comparisons showing little differences between AN and atypical AN, we view a single disorder as the most parsimonious explanation. Etiological models need to particularly account for the strong relationship between weight loss and premorbid body weight.

No relationship between male pubertal timing and depression - new insights from epidemiology and Mendelian randomization

BACKGROUND

In males, the relationship between pubertal timing and depression is understudied and less consistent than in females, likely for reasons of unmeasured confounding. To clarify this relationship, a combined epidemiological and genetic approach was chosen to exploit the methodological advantages of both approaches.

METHODS

Data from 2026 males from a nationwide, representative study were used to investigate the non-/linear relationship between pubertal timing defined by the age at voice break and depression, considering a multitude of potential confounders and their interactions with pubertal timing. This analysis was complemented by Mendelian randomization (MR), which is robust to inferential problems inherent to epidemiological studies. We used 71 single nucleotide polymorphisms related to pubertal timing in males as instrumental variable to clarify its causal relationship with depression based on data from 807 553 individuals (246 363 cases and 561 190 controls) by univariable and multivariable MR, including BMI as pleiotropic phenotype.

RESULTS

Univariable MR indicated a causal effect of pubertal timing on depression risk (inverse-variance weighted: OR 0.93, 95%-CI [0.87-0.99)], p = 0.03). However, this was not confirmed by multivariable MR (inverse-variance weighted: OR 0.95, 95%-CI [0.88-1.02)], p = 0.13), consistent with the epidemiological approach (OR 1.01, 95%-CI [0.81-1.26], p = 0.93). Instead, the multivariable MR study indicated a causal relationship of BMI with depression by two of three methods.

CONCLUSIONS

Pubertal timing is not related to MDD risk in males.

The Diagnosis and Treatment of Anorexia Nervosa in Childhood and Adolescence

BACKGROUND

Anorexia nervosa (AN) is a serious disease with a lifetime prevalence of up to 3.6% in women and 0.3% in men. Abnormally low weight and the associated starvation partly account for its somatic and mental manifestations.

METHODS

This review is based on publications retrieved by a selective search concerning AN in childhood and adolescence.

RESULTS

The peak age of onset of AN is 15.5 years. The frequency of inpatient treatment for AN rose by 40% during the COVID pandemic, indicating the importance of environmental factors; the heritability of AN is estimated at 0.5. The ICD-11 sets the threshold for AN-associated underweight at the fifth percentile for age of the body mass index, as long as the remaining diagnostic criteria are met. The main goal of the multiprofessional treatment of AN is the return to normal body weight, which is a central prerequisite for regaining somatic and mental health. The mean duration of AN is 3.4 years, and approximately two-thirds of patients recover from the disease over the long term.

CONCLUSION

Marked weight loss in childhood and adolescence can trigger AN in the presence of a predisposition to this disease. Patients and their families should receive psychoeducation regarding the symptoms of starvation and their overlap with those of AN. Important objectives are to shorten the duration of the illness, minimize mortality and the risk of chronic illness, and to identify pharmacological approaches to treatment.

Case report: clinical improvements observed in first off-label metreleptin treatment of a patient with atypical anorexia nervosa

Off-label metreleptin treatment resulted in cognitive, emotional and behavioral improvements of patients with anorexia nervosa, who presented with hypoleptinemia. We now report a case study of a 16-year-old female patient with atypical anorexia nervosa who was treated off-label with metreleptin for 11 days. She had lost 21 kg over 6 months. Her body mass index at referral for inpatient treatment was 20 kg/m2, her serum leptin level was just within the normal range (2.4 ng/ml). Dosing resulted in prominent improvements of mood and weight phobia entailing a comparatively brief inpatient treatment. The observed improvements are similar to those observed in patients with AN, suggesting overlapping mechanisms with respect to clinical effects induced by elevations of absolute or relative hypoleptinemia. Randomized controlled trials are warranted for both eating disorders.

Evaluation of the MC3R gene pertaining to body weight and height regulation and puberty development

Recent studies reported an impact of the melanocortin 3 receptor (MC3R) on the regulation of body weight, linear growth and puberty timing. Previously, allele p.44Ile of a frequent non-synonymous variant (NSV) p.Val44Ile was reported to be associated with decreased lean body mass (LBM) and later puberty in both sexes. We Sanger sequenced the coding region of MC3R in 185 children or adolescents with short normal stature (SNS) or 258 individuals with severe obesity, and 192 healthy-lean individuals. Eleven variants (six NSVs) were identified. In-silico analyses ensued. Three rare loss-of-function (LoF) variants (p.Phe45Ser, p.Arg220Ser and p.Ile298Ser) were only found in severely obese individuals. One novel highly conserved NSV (p.Ala214Val), predicted to increase protein stability, was detected in a single lean female. In the individuals with SNS, we observed deviation from Hardy-Weinberg Equilibrium (HWE) (p = 0.012) for p.Val44Ile (MAF = 11.62%). Homozygous p.44Ile carriers with SNS had an increased BMI, but this effect did not remain significant after Bonferroni correction. In line with previous findings, the detected LoF NSVs may suggest that dysfunction in MC3R is associated with decreased body height, obesity and delayed puberty.

Genetic variants in genes involved in creatine biosynthesis in patients with severe obesity or anorexia nervosa

Increased thermogenesis in brown adipose tissue might have an obesity-reducing effect in humans. In transgenic mice, depletion of genes involved in creatine metabolism results in disrupted thermogenic capacity and altered effects of high-fat feeding on body weight. Data analyses of a sex-stratified genome-wide association study (GWAS) for body mass index (BMI) within the genomic regions of genes of this pathway (CKB, CKMT1B, and GATM) revealed one sex-dimorphic BMI-associated SNP in CKB (rs1136165). The effect size was larger in females than in males. A mutation screen of the coding regions of these three candidate genes in a screening group (192 children and adolescents with severe obesity, 192 female patients with anorexia nervosa, and 192 healthy-lean controls) identified five variants in each, CKB and GATM, and nine variants in the coding sequence of CKMT1B. Non-synonymous variants identified in CKB and CKMT1B were genotyped in an independent confirmation study group (781 families with severe obesity (trios), 320 children and adolescents with severe obesity, and 253 healthy-lean controls). In silico tools predicted mainly benign yet protein-destabilizing potentials. A transmission disequilibrium test in trios with severe obesity indicated an obesity-protective effect of the infrequent allele at rs149544188 located in CKMT1B. Subsequent correlation analyses in 1,479 individuals of the Leipzig Obesity BioBank revealed distinct correlations of CKB with the other two genes in omental visceral adipose tissue (VAT) and abdominal subcutaneous adipose tissue (SAT). Furthermore, between-subject comparisons of gene expression levels showed generally higher expressions of all three genes of interest in VAT than in SAT. Future in vitro analyses are needed to assess the functional implications of these findings.

Lipocalin 2 - mutation screen and serum levels in patients with anorexia nervosa or obesity and in lean individuals

CONTEXT

The bone-derived adipokine lipocalin-2 is relevant for body weight regulation by stimulating the leptin-melanocortin pathway.

OBJECTIVE

We aimed to (i) detect variants in the lipocalin-2 gene (LCN2) which are relevant for body weight regulation and/or anorexia nervosa (AN); (ii) describe and characterize the impact of LCN2 and MC4R variants on circulating lipocalin-2 level.

METHODS

Sanger sequencing of the coding region of LCN2 in 284 children and adolescents with severe obesity or 287 patients with anorexia nervosa. In-silico analyses to evaluate functional implications of detected LCN2 variants. TaqMan assays for rare non-synonymous variants (NSVs) in additional independent study groups. Serum levels of lipocalin-2 were measured by ELISA in 35 females with NSVs in either LCN2 or MC4R, and 33 matched controls without NSVs in the two genes.

RESULTS

Fourteen LCN2-variants (five NSVs) were detected. LCN2-p.Leu6Pro and p.Gly9Val located in the highly conserved signal peptide region may induce functional consequences. The secondary structure change of lipocalin-2 due to LCN2-p.Val89Ile may decrease solubility and results in a low lipocalin-2 level in a heterozygotes carrier (female recovered from AN). Lean individuals had lower lipocalin-2 levels compared to patients with obesity (p = 0.033).

CONCLUSION

Lipocalin-2 levels are positively associated with body mass index (BMI). Single LCN2-variants might have a profound effect on lipocalin-2 levels.

Age at menarche relates to depression in adolescent girls: Comparing a clinical sample to the general pediatric population

CONTEXT

The timing of puberty, physical features of pubertal development, and hormones are closely intertwined but may also individually contribute to the risk for depression and depression severity. Additionally, their effects on mood may depend on depression severity, but previously this has only been studied in mostly subclinical depression.

METHODS

In 184 girls from a single psychiatric hospital with significant depressive symptoms (Beck Depression Inventory-II score > 13), the relationship between depression severity and age at menarche (AAM), pubertal status, and gonadal/adrenal hormones (estradiol, progesterone, DHEA-S, androstenedione, testosterone, dihydrotestosterone) was investigated. Moreover, AAM in depressed girls was compared to that from a representative sample of German adolescents without a psychiatric disorder (N = 1674). Androgen levels were compared to those of age- and sex-matched controls (N = 59).

RESULTS

AAM but not pubertal stage or biochemical parameters related to depression. Girls with AAM at the lower normative range of pubertal development were 61 % more likely to develop depression and scored 4.9 points higher on the depression scale than girls experiencing menarche at the population average. Androstenedione levels were increased in the psychiatric sample, but neither androgen nor gonadal hormone levels were associated with depression severity.

LIMITATIONS

The study is cross-sectional.

CONCLUSIONS

These observations confirm previous studies in mostly subclinical depression and highlight the importance of AAM for adolescent depression. Thus, AAM could be considered a prognostic factor for a clinical risk score assessing the probability of adolescent depression. Moreover, these findings suggest fostering efforts that address risk factors that contribute to an earlier AAM.

The role of hypoleptinemia in the psychological and behavioral adaptation to starvation: implications for anorexia nervosa

This narrative review aims to pinpoint mental and behavioral effects of starvation, which may be triggered by hypoleptinemia and as such may be amenable to treatment with leptin receptor agonists. The reduced leptin secretion results from the continuous loss of fat mass, thus initiating a graded triggering of diverse starvation related adaptive functions. In light of leptin receptors located in several peripheral tissues and many brain regions adaptations may extend beyond those of the hypothalamus-pituitary-end organ-axes. We focus on gastrointestinal tract and reward system as relevant examples of peripheral and central effects of leptin. Despite its association with extreme obesity, congenital leptin deficiency with its many parallels to a state of starvation allows the elucidation of mental symptoms amenable to treatment with exogenous leptin in both ob/ob mice and humans with this autosomal recessive disorder. For starvation induced behavioral changes with an intact leptin signaling we particularly focus on rodent models for which proof of concept has been provided for the causative role of hypoleptinemia. For humans, we highlight the major cognitive, emotional and behavioral findings of the Minnesota Starvation Experiment to contrast them with results obtained upon a lesser degree of caloric restriction. Evidence for hypoleptinemia induced mental changes also stems from findings obtained in lipodystrophies. In light of the recently reported beneficial cognitive, emotional and behavioral effects of metreleptin-administration in anorexia nervosa we discuss potential implications for the treatment of this eating disorder. We postulate that leptin has profound psychopharmacological effects in the state of starvation.

Evidence for correlations between BMI-associated SNPs and circRNAs

Circular RNAs (circRNAs) are regulators of processes like adipogenesis. Their expression can be modulated by SNPs. We analysed links between BMI-associated SNPs and circRNAs. First, we detected an enrichment of BMI-associated SNPs on circRNA genomic loci in comparison to non-significant variants. Analysis of sex-stratified GWAS data revealed that circRNA genomic loci encompassed more genome-wide significant BMI-SNPs in females than in males. To explore whether the enrichment is restricted to BMI, we investigated nine additional GWAS studies. We showed an enrichment of trait-associated SNPs in circRNAs for four analysed phenotypes (body height, chronic kidney disease, anorexia nervosa and autism spectrum disorder). To analyse the influence of BMI-affecting SNPs on circRNA levels in vitro, we examined rs4752856 located on hsa_circ_0022025. The analysis of heterozygous individuals revealed an increased level of circRNA derived from the BMI-increasing SNP allele. We conclude that genetic variation may affect the BMI partly through circRNAs.

Causal Effect of Age at Menarche on the Risk for Depression: Results From a Two-Sample Multivariable Mendelian Randomization Study

A fair number of epidemiological studies suggest that age at menarche (AAM) is associated with depression, but the reported effect sizes are small, and there is evidence of residual confounding. Moreover, previous Mendelian randomization (MR) studies to avoid inferential problems inherent to epidemiological studies have provided mixed findings. To clarify the causal relationship between age at menarche and broadly defined depression risk, we used 360 genome-wide significantly AAM-related single-nucleotide polymorphisms (SNPs) as instrumental variable and data from the latest GWAS for the broadly defined depression risk on 807,553 individuals (246,363 cases and 561,190 controls). Multiple methods to account for heterogeneity of the instrumental variable (penalized weighted median, MR Lasso, and contamination mixture method), systematic and idiosyncratic pleiotropy (MR RAPS), and horizontal pleiotropy (MR PRESSO and multivariable MR using three methods) were used. Body mass index, education attainment, and total white blood count were considered pleiotropic phenotypes in the multivariable MR analysis. In the univariable [inverse-variance weighted (IVW): OR = 0.96, 95% confidence interval = 0.94–0.98, p = 0.0003] and multivariable MR analysis (IVW: OR = 0.96, 95% confidence interval = 0.94–0.99, p = 0.007), there was a significant causal effect of AAM on depression risk. Thus, the present study supports conclusions from previous epidemiological studies implicating AAM in depression without the pitfalls of residual confounding and reverse causation. Considering the adverse consequences of an earlier AAM on mental health, this finding should foster efforts to address risk factors that promote an earlier AAM.

Affinity purification of in vivo assembled whirlin-associated protein complexes from the zebrafish retina

Mutations in WHRN lead to Usher syndrome type 2d or to non-syndromic hearing impairment. The WHRN-encoded gene product whirlin directly interacts with the intracellular regions of the other two Usher syndrome type 2-associated proteins, usherin and ADGRV1. In photoreceptor cells, this protein complex constitutes fibrous links between the periciliary membrane and the connecting cilium. However, the molecular mechanism(s) of retinal degeneration due to compromised formation and function of the USH2-associated protein complex remains elusive. To unravel this pathogenic mechanism, we isolated and characterized whirlin-associated protein complexes from zebrafish photoreceptor cells. We generated transgenic zebrafish that express Strep/FLAG-tagged Whrna, a zebrafish ortholog of human whirlin, under the control of a photoreceptor-specific promoter. Affinity purification of Strep/FLAG-tagged Whrna and associated proteins from adult transgenic zebrafish retinas followed by mass spectrometry identified 19 novel candidate associated proteins. Pull down experiments and dedicated yeast two-hybrid assays confirmed the association of Whrna with 7 of the co-purified proteins. Several of the co-purified proteins are part of the synaptic proteome, which indicates a role for whirlin in the photoreceptor synapse. Future studies will elucidate which of the newly identified protein-protein interactions contribute to the development of the retinal phenotype observed in USH2d patients. SIGNIFICANCE: Since protein-protein interactions identified using targeted in vitro studies do not always recapitulate interactions that are functionally relevant in vivo, we established a transgenic zebrafish line that stably expresses a Strep/FLAG-tagged ortholog of human whirlin (SF-Whrna) in photoreceptor cells. Affinity purification of in vivo-assembled SF-Whrna-associated protein complexes from retinal lysates followed by mass spectrometry, identified 19 novel candidate interaction partners, many of which are enriched in the synaptic proteome. Two human orthologs of the identified candidate interaction partners, FRMPD4 and Kir2.3, were validated as direct interaction partners of human whirlin using a yeast two-hybrid assay. The strong connection of whirlin with postsynaptic density proteins was not identified in previous in vitro protein-protein interaction assays, presumably due to the absence of a biologically relevant context. Isolation and identification of in vivo-assembled whirlin-associated protein complexes from the tissue of interest is therefore a powerful methodology to obtain novel insight into tissue specific protein-protein interactions and has the potential to improve significantly our understanding of the function of whirlin and the molecular pathogenesis underlying Usher syndrome type 2.

Suggestive Evidence for an Antidepressant Effect of Metreleptin Treatment in Patients with Lipodystrophy

INTRODUCTION

Lipodystrophy (LD) syndromes are rare heterogeneous disorders characterized by reduction or absence of subcutaneous fat, low or nondetectable leptin concentrations in blood and impaired hunger/satiety regulation. Metreleptin treatment reverses metabolic complications and improves eating behavior in LD. Because depression in anorexia nervosa (AN), which is also characterized by hypoleptinemia, improves substantially upon treatment with metreleptin, we hypothesized that metreleptin substitution may be associated with an antidepressant effect in patients with LD, too.

METHODS

In this ancillary study, 10 adult patients with LD were treated with metreleptin. To assess depressive symptoms, the self-rating questionnaire Beck's Depression Inventory (BDI) was filled in at preestablished time points prior (T1) and after initiation of metreleptin (T2: 1 week; T3: 4 weeks; T4: 12 weeks) dosing. The differences between time points were tested with nonparametric Friedman's analysis of variance. Sensitivity analyses were performed upon exclusion of the BDI items addressing appetite and weight changes.

RESULTS

According to their BDI scores, 4 patients had mild depression and 2 had moderate depression at baseline. Friedman's test revealed significant differences in BDI scores between the four time points. Post hoc analyses revealed that the difference between T1 and T3 was significant upon Bonferroni correction (p = 0.034, effect size r = 0.88). The sensitivity analyses upon exclusion of the appetite and weight change items again revealed a significant Friedman's test and significant Bonferroni corrected differences in the revised BDI scores between T1 versus T2 (p = 0.002, r = 0.99) and T1 versus T3 (p = 0.007, r = 0.79).

DISCUSSION/CONCLUSION

Our study for the first time revealed suggestive evidence for an antidepressant effect of metreleptin in patients with LD. Metreleptin caused a rapid drop in depression scores within 1 week of treatment. A reduction of the depression score was also observed in 2 of the 3 LD patients whose BDI scores were in the normal range before start of the treatment. The reduction in total scores of BDI was still apparent after 3 months (T4) of dosing. This observation matches findings obtained in clinical case studies of AN patients, in whom depression scores also dropped during the first week of metreleptin treatment. It needs to be noted that by the nature of this observational study without a placebo group, nonspecific treatment expectation affecting mood cannot fully be ruled out.

Reasons for admission and variance of body weight at referral in female inpatients with anorexia nervosa in Germany

BACKGROUND

Body mass index (BMI) at hospital admission in patients with anorexia nervosa (AN) represents a prognostic marker for mortality, chronicity and future body weight. The current study focused on the associations between BMI standard deviation score (BMI-SDS) at admission and reasons for seeking inpatient treatment. Further interest was given to the relationship between premorbid weight and weight at admission, as well as the effect of both weight at referral and reasons for admission on treatment outcome.

METHODS

Data ascertained in the German Register of Children and Adolescents with AN were analysed to assess the parental and patient overlap for 23 predefined reasons for admission, using factor analyses and regressions models.

RESULTS

Complete parent-patient data sets were available for 360 patients out of 769. The highest consensus rates between parents and patients were obtained for weight and eating behavior related reasons and hyperactivity. Based on factor analysis, four factors emerged. Premorbid BMI-SDS, age and 'low body weight' as stated by patients or parents explained almost 40% of the variance of the BMI-SDS at admission.

CONCLUSIONS

Results underscore the relevance of age and premorbid BMI for BMI at admission. Only single reasons for admission explained further variance, with 'low body weight' having the largest effect. Approximately 40% of the variance of BMI-SDS was explained. For the first time, the effect of premorbid BMI for BMI at admission was robustly demonstrated in a multicenter study. Of the variance in BMI-SDS at discharge, our model could explain 37%, with reasons for admission having a small effect. Further investigation of the reasons for admission would be worthwhile to improve treatment and prognosis.

Suggestive Evidence for Causal Effect of Leptin Levels on Risk for Anorexia Nervosa: Results of a Mendelian Randomization Study

Genetic correlations suggest a coexisting genetic predisposition to both low leptin levels and risk for anorexia nervosa (AN). To investigate the causality and direction of these associations, we performed bidirectional two-sample Mendelian randomization (MR) analyses using data of the most recent genome-wide association study (GWAS) for AN and both a GWAS and an exome-wide-association-study (EWAS) for leptin levels. Most MR methods with genetic instruments from GWAS showed a causal effect of lower leptin levels on higher risk of AN (e.g. IVW b = -0.923, p = 1.5 × 10^-4). Because most patients with AN are female, we additionally performed analyses using leptin GWAS data of females only. Again, there was a significant effect of leptin levels on the risk of AN (e.g. IVW b = -0.826, p = 1.1 × 10^-04). MR with genetic instruments from EWAS showed no overall effect of leptin levels on the risk for AN. For the opposite direction, MR revealed no causal effect of AN on leptin levels. If our results are confirmed in extended GWAS data sets, a low endogenous leptin synthesis represents a risk factor for developing AN.

A mendelian randomization study on causal effects of 25(OH)vitamin D levels on attention deficit/hyperactivity disorder

BACKGROUND

While observational studies revealed an inverse association between serum 25(OH)vitamin D (25(OH)D) and the risk of attention deficit/hyperactivity disorder (ADHD), the causality of this relationship remains unclear.

METHODS

We conducted a bidirectional two-sample Mendelian Randomization (MR) study to examine whether 25(OH)D has an effect on the risk to develop ADHD or vice versa. Information on single nucleotide polymorphisms (SNP) associated with serum 25(OH)D was obtained from a genome-wide association study (GWAS) considering phenotype data from 79,366 individuals of European ancestry. Data on risk for ADHD were derived from a GWAS analysis with 20,183 individuals diagnosed with ADHD and 35,191 controls. For our analysis, we considered effect sizes based on the European participants (19,099 cases and 34,194 controls).

RESULTS

Single SNP analyses showed a causal effect of vitamin D on ADHD risk for only one SNP (rs12785878, p = 0.024). The overall MR estimates did not reveal a causal effect of 25(OH)D on risk for ADHD. In the reverse analysis, neither any single nor the multi-SNP MR analyses showed a causal effect of ADHD on 25(OH)D.

CONCLUSION

Results from this two-sample MR study did not confirm a causal effect of 25(OH)D on ADHD or vice versa. Accordingly, our study does not provide evidence that improving 25(OH)D via supplementation could reduce the risk of developing ADHD.

[Genetic Analyses of Complex Phenotypes Through the Example of Anorexia Nervosa and Bodyweight Regulation]

Genetic Analyses of Complex Phenotypes Through the Example of Anorexia Nervosa and Bodyweight Regulation Abstract. Genetics variants are important for the regulation of bodyweight and also contribute to the genetic architecture of eating disorders. For many decades, family studies, a subentity of so-called formal genetic studies, were employed to determine the genetic share of bodyweight and eating disorders and found heritability rates exceeding 50 % with both phenotypes. Because of this significant contribution of genetics, the search for those genes and their variants related to the variance in bodyweight and the etiology of eating disorders - or both - was commenced by the early 1990s. Initially, candidate genes studies were conducted targeting those genes most plausibly related to either phenotype, especially based on pathophysiological considerations. This approach, however, implicated only a few genes in the regulation of bodyweight and did not provide significant insights into the genetics of eating disorders. Driven by considerable methodological advances in genetic research, especially related to the introduction of so-called genome-wide association studies by the beginning of the 21st century, today more than 1,000 variants/loci have been detected that affect the regulation of bodyweight. Eight such loci have been identified regarding anorexia nervosa (AN). These results as well as those from cross-disorder analyses provide insights into the complex regulation of bodyweight and demonstrated unforeseen pathomechanisms for AN.

[Nutrition and mental health - how findings from genetic studies can support the identification of dietary effects]

Nutrition and mental health - how findings from genetic studies can support the identification of dietary effects Abstract. Introduction: Numerous studies indicate that dietary interventions could be an important approach to the prevention and treatment of mental disorders. However, conventional nutritional epidemiological approaches (e. g., observational studies and randomized controlled trials, RCTs) have specific limitations to consider when interpreting the results. This article examines whether genetic studies could help to establish a link between diet and the prevention of mental disorders. Furthermore, it examines whether it is possible to draw conclusions about causal relationships. Methods: This narrative review describes various approaches of genetic cross-phenotype studies and presents examples of their applications in nutritional psychiatry. In addition, it discusses specific requirements as well as the strengths and limitations of the respective approaches. Results: To date, in the context of nutritional psychiatry, genetic correlation analyses, look-up analyses, and Mendelian randomization (MR) studies have been used for genetic crossphenotype analyses. Genetic correlation and look-up analyses provide initial evidence of possible overlap between specific mental disorders and metabolic pathways or specific nutrients. MR studies are used for detailed analyses that aim to identify causal relationships. However, MR is based on specific assumptions that must be met and considered when results are interpreted. Conclusion: Genetic cross-phenotype analyses are a useful amendment to conventional nutritional epidemiological research. In particular, positive results from MR studies provide an important fundament for identifying and developing suitable dietary interventions, which in turn increases the chance of success upon testing in subsequent RCTs. Accordingly, genetic cross-phenotype analyses are important instruments for increasing the efficiency in nutritional psychiatric research.

Long-term effects of laparoscopic sleeve gastrectomy and Roux-Y-gastric bypass on body composition and bone mass density

Objective

Currently, the two most common bariatric procedures are laparoscopic sleeve gastrectomy (LSG) and laparoscopic gastric bypass (LRYGB). Long-term data comparing the two interventions in terms of their effect on body composition and bone mass density (BMD) is scarce. The aim of this study was to assess body composition and BMD at least five years after sleeve gastrectomy (LSG) and gastric bypass (LRYGB).

Methods

Bariatric patients at least five years post-surgery (LSG or LRYGB) were recruited and body composition and BMD was measured by means of DEXA. Data from body composition before surgery was included in the analysis. Blood samples were taken for determination of plasma calcium, parathyroid hormone (PTH), Vitamin D3, alkaline phosphatase and C-terminal telopeptide (CTX), and individual risk for osteoporotic fracture assessed by The Fracture Risk Assessment Tool (FRAX) score was calculated. After surgery, all patients received multivitamins, vitamin D3, and zinc. In addition, LRYGB-patients were prescribed calcium.

Results

A total of 142 patients were included, 72 LSG and 70 LRYGB, before surgery: median BMI 43.1 kg/m2, median age 45.5 years, 62.7% females. Follow-up after a median of 6.7 years. For LRYGB, percentage total weight loss (%TWL) at follow up was 26.3%, and for LSG 24.1%, (p = 0.243). LRYGB lead to a slightly lower fat percentage in body composition. At follow-up, 45% of both groups had a T-score at the femoral neck below -1, indicating osteopenia. No clinically relevant difference between the groups in BMD was found.

Conclusion

At 6.7 years post-surgery, no difference in body composition and BMD between LRYGB and LSG was found. Deficiencies and bone loss remain an issue after both interventions and should be monitored.

Long-term effects of laparoscopic sleeve gastrectomy: What are the results beyond 10 years?

Objective

Sleeve gastrectomy (SG) has become the most commonly performed bariatric procedure worldwide. Newer studies providing long-term follow-up are showing high incidence of weight regain and high incidence of de novo reflux or worsening of preexisting GERD leading to conversion to different bariatric procedure. The objective of our study was to present 5 to 15-year follow-up results in terms of weight loss, remission of comorbidities and reoperation rate.

Methods

This is a retrospective analysis of prospectively collected data. The minimal follow-up time was 5 years. Patients who underwent SG between August 2004 and December 2014 were included. In case of reoperation patients were converted to Roux-en-Y gastric bypass or biliopancreatic diversion type duodenal-switch with or without hiatal hernia repair.

Results

A total of 307 patients underwent SG either as primary bariatric procedure (n = 262) or as redo operation after failed laparoscopic gastric banding (n = 45). Mean body mass index at time of primary SG was 46.4 ± 8.0 kg/m2. Mean age at operation was 43.7 ± 12.4 years with 68% females. Follow-up was 84% and 70% at 5 and 10 years respectively. The mean EBMIL for primary SG was 62.8 ± 23.1% after 5 years, 53.6 ± 24.6% after 10 years and 51.2 ± 20.3% after 13 years. Reoperation after SG was necessary in almost every fifth SG patient: 24 patients (7.8%) were reoperated due to insufficient weight loss, 12 patients (3.9 %) due to reflux, while 23 patients (7.5%) needed conversion due to both, insufficient weight loss and reflux. Comorbidities improved considerably while the incidence of new onset reflux was 29.7%.

Conclusion

SG provides a long-term EBMIL from 51 to 54% beyond 10 years and a significant improvement of comorbidities. On the other hand, a high incidence of both weight loss failure and de novo reflux was observed leading to conversion.

Does the non-absorbable suture closure of the jejunal mesenteric defect reduce the incidence and severity of internal hernias after laparoscopic Roux-en-Y gastric bypass?

Objective

Internal hernias (IH) are frequent complications after laparoscopic Roux-en-Y gastric bypass (LRYGB). Closure of the jejunal mesenteric and the Petersen defect reduces IH incidence in prospective and retrospective trials. This study investigates whether closing the jejunal mesenteric space alone by non-absorbable suture and splitting the omentum can be beneficial to prevent IH after LRYGB.

Methods

Observational cohort study of 785 patients undergoing linear LRYGB including omental split at a single institution, 493 without jejunal mesenteric defect closure, 292 with closure by non-absorbable suture with a minimal follow-up of 2 years. Patients were assessed for appearance and severity of IH. Additionally, open mesenteric gaps without herniated bowel, as well as early obstructions due to kinking of the entero-enterostomy (EE) were explored.

Results

By primary mesenteric defect closure, the rate of manifest jejunal mesenteric and Petersen IH could be reduced from 6.5% to 3.8%, but without reaching statistical significance. The most common location for an IH was the jejunal mesenteric space, where defect closure during primary surgery could reduce the rate of IH from 5.3% to 2.4%. Higher weight loss seemed to increase the risk of developing an IH.

Conclusion

The closure of the jejunal mesenteric defect by non-absorbable suture can reduce the rate of IH at the jejunal mesenteric space after LRYGB. However, the beneficial effect in our collective is smaller than expected, especially in patients with excellent weight loss. Petersen IH rate remained low by consequent T-shape split of the omentum without suturing of the defect.

Increased Prevalence of Subclinical Hypothyroidism and Thyroid Autoimmunity in Depressed Adolescents: Results From a Clinical Cross-Sectional Study in Comparison to the General Pediatric Population

OBJECTIVE

The study was undertaken to determine the prevalence of subclinical and overt thyroid dysfunction as well as thyroid autoimmunity in depressed adolescents in comparison to the general pediatric population. Additionally, the relationship between parameters of thyroid function and Beck Depression Inventory-II (BDI-II) scores was examined.

METHODS

Parameters of thyroid function (thyrotropin, free thyroxine, thyroid peroxidase antibodies) and prevalence of thyroid dysfunction and autoimmunity were determined in 360 adolescents (11-19 years) with at least mild depression (BDI-II score > 13) between June 2016 and December 2019 and in a representative reference cohort without evidence of impaired mental health from a nationwide survey (German Health Interview and Examination Survey for Children and Adolescents [KiGGS], 2003-2006).

RESULTS

There was a higher prevalence of thyroid peroxidase antibody positivity in depressed adolescents (mean ± SD BDI-II, 30.0 ± 10.4) compared to KiGGS participants (depressed adolescents: 5.8%, 95% CI [3.7-8.6]; odds ratio [OR] 1.9, P = .009, d = 0.36; KiGGS participants: 3.1%, 95% CI [2.5-3.9]). The prevalence of subclinical hypothyroidism was likewise higher in depressed adolescents (9.1%, 95% CI [6.3-12.4] vs KiGGS participants: 2.1%, 95% CI [1.6-2.7]; OR 4.7, P < .001, d = 0.85), but no other types of thyroid dysfunction had a higher prevalence. There was no significant relationship between parameters of thyroid function and BDI-II scores, as examined by multiple regression considering relevant covariates. The positive results were verified in a subsample of patients with a confirmed diagnosis of depression (N = 284).

CONCLUSIONS

The prevalence of subclinical hypothyroidism and of thyroid autoimmunity in depressed adolescents is increased. The etiology of these observations is not well understood, and further studies to examine the underlying relationship are required. Moreover, thyroid autoimmunity may constitute an additional risk factor for depression on its own.

Effect of vitamin D deficiency on depressive symptoms in child and adolescent psychiatric patients: results of a randomized controlled trial

PURPOSE

While observational studies revealed inverse associations between serum vitamin D levels [25(OH)D] and depression, randomized controlled trials (RCT) in children and adolescents are lacking. This RCT examined the effect of an untreated vitamin D deficiency compared to an immediate vitamin D3 supplementation on depression scores in children and adolescents during standard day and in-patient psychiatric treatment.

METHODS

Patients with vitamin D deficiency [25(OH)D ≤ 30 nmol/l] and at least mild depression [Beck Depression Inventory II (BDI-II) > 13] (n = 113) were 1:1 randomized into verum (VG; 2640 IU vitamin D3/d) or placebo group (PG) in a double-blind manner. During the intervention period of 28 days, both groups additionally received treatment as usual. BDI-II scores were assessed as primary outcome, DISYPS-II (Diagnostic System for Mental Disorders in Childhood and Adolescence, Self- and Parent Rating) and serum total 25(OH)D were secondary outcomes.

RESULTS

At admission, 49.3% of the screened patients (n = 280) had vitamin D deficiency. Although the intervention led to a higher increase of 25(OH)D levels in the VG than in the PG (treatment difference: + 14 ng/ml; 95% CI 4.86-23.77; p = 0.003), the change in BDI-II scores did not differ (+ 1.3; 95% CI - 2.22 to 4.81; p = 0.466). In contrast, DISYPS parental ratings revealed pronounced improvements of depressive symptoms in the VG (- 0.68; 95% CI - 1.23 to - 0.13; p = 0.016).

CONCLUSION

Whereas this study failed to show a vitamin D supplementation effect on self-rated depression in adolescent in- or daycare patients, parents reported less depressive symptoms in VG at the end of our study. Future trials should consider clinician-rated depressive symptoms as primary outcome.

TRIAL REGISTRATION

"German Clinical Trials Register" ( https://www.drks.de ), registration number: DRKS00009758.

Risk factors for a low weight gain in the early stage of adolescent anorexia nervosa inpatient treatment: findings from a pilot study

PURPOSE

Body weight restoration is a major treatment aim in juvenile inpatients with anorexia nervosa (AN) (i.e., 500-1000 g/week according to the German guidelines). Several studies suggest the early weight gain to be crucial for remission. The identification of patients at risk of a low early weight gain could enable an adequate adaptation of treatment. Thus, we aimed at detecting risk factors of a low weight gain during inpatient treatment.

METHODS

The presented work analyzes data from a pilot study in 30 female adolescent inpatients with AN (restricting subtype; age range at admission: 12.6-17.6 years). Premorbid characteristics, history of symptomatology, anthropometric data, and eating-disorder psychopathology were compared between those who gained at least an average of 500 g/week during the first 7 weeks of treatment (high weight gainers, HWG) and those who did not (low weight gainers, LWG).

RESULTS

At admission, LWG (n = 15) had a significantly higher BMI(-SDS) and scored significantly higher in the eating-disorder examination questionnaire (EDE-Q) than HWG (n = 15). A logistic regression analysis indicated both parameters to be independently associated with a low weight gain.

CONCLUSION

Higher EDE-Q scores seem to be a major risk factor for a low weight gain at the beginning of treatment. Moreover, a higher BMI(-SDS) at admission does not necessarily indicate a less severe AN symptomatic, as it was associated with a lower weight gain in our sample during the first 7 weeks of treatment. Reassessment of our results in larger studies is required to draw firm conclusions for clinical practice.

LEVEL OF EVIDENCE

Level V.

0529 Behavioral Therapy Components for Insomnia and Fatigue in COPD

Introduction

Insomnia contributes to fatigue, a common symptom in COPD. Our study aims were: (1) to determine the efficacy of a) cognitive behavioral therapy for insomnia (CBT-I) and b) COPD education (COPD-ED) on insomnia and fatigue, and (2) to define potential mechanistic contributors to pre/post intervention change in insomnia and fatigue in patients with COPD and insomnia.

Methods

A randomized 2x2 factorial design was used with factors representing CBT-I (yes/no) and COPD-ED (yes/no). Attention control (health videos) were used in the absence of CBT-I or COPD-ED. All patients received 6, 75-minute weekly sessions. Dependent variables included insomnia severity (Sleep Impairment Index (SII), range 0-28) and fatigue (Chronic Respiratory Disease Questionnaire (CRQ) range 1-7) measured at baseline, just post-intervention, and at 3-months post-intervention.

Results

One hundred nine patients (FEV1% predicted 67 ± 24% (mean ± SD), age 65 ± 8 years, SII 15.9 ± 8, CRQ 3.7 ± 1.1) participated in the study. After 6 sessions, insomnia decreased more in patients who received CBT-I (-5.8) than those who did not (-2.2; p=0.0002). This effect was sustained at the 3-month follow-up (p=0.0003). Fatigue showed no significant differences for CBT-I at 6-weeks (p=.27) but at 3-months patients receiving CBT-I showed marginally better improvement (.75, a clinically important difference) compared to those who did not receive CBT-I (.43; p=.09). COPD-ED showed no effect on insomnia or fatigue. Two main effects suggest mechanisms for the pre-post efficacy of CBT-I: improved sleep beliefs (p=0.0257) and self-efficacy for sleep (p=0.0619) after 6 sessions which were sustained at 3 months (p=0.0184 and p=0.0431 respectively).

Conclusion

CBT-I produced sustained decreases in insomnia in patients with COPD. Results suggest that changes in beliefs about sleep and improved self-efficacy for managing sleep may mediate CBT-I associated decreases in insomnia.

Support

This research was supported by the National Institute of Nursing Research of the National Institutes of Health R01NR013937.

The Role of Genetic Variation of BMI, Body Composition, and Fat Distribution for Mental Traits and Disorders: A Look-Up and Mendelian Randomization Study

Anthropometric traits and mental disorders or traits are known to be associated clinically and to show genetic overlap. We aimed to identify genetic variants with relevance for mental disorders/traits and either (i) body mass index (or obesity), (ii) body composition, (and/or) (iii) body fat distribution. We performed a look-up analysis of 1,005 genome-wide significant SNPs for BMI, body composition, and body fat distribution in 15 mental disorders/traits. We identified 40 independent loci with one or more SNPs fulfilling our threshold significance criterion (P < 4.98 × 10^–5) for the mental phenotypes. The majority of loci was associated with schizophrenia, educational attainment, and/or intelligence. Fewer associations were found for bipolar disorder, neuroticism, attention deficit/hyperactivity disorder, major depressive disorder, depressive symptoms, and well-being. Unique associations with measures of body fat distribution adjusted for BMI were identified at five loci only. To investigate the potential causality between body fat distribution and schizophrenia, we performed two-sample Mendelian randomization analyses. We found no causal effect of body fat distribution on schizophrenia and vice versa. In conclusion, we identified 40 loci which may contribute to genetic overlaps between mental disorders/traits and BMI and/or shape related phenotypes. The majority of loci identified for body composition overlapped with BMI loci, thus suggesting pleiotropic effects.

Assessing causal links between metabolic traits, inflammation and schizophrenia: a univariable and multivariable, bidirectional Mendelian-randomization study

BACKGROUND

Blood immunoreactive biomarkers, such as C-reactive protein (CRP), and metabolic abnormalities have been associated with schizophrenia. Studies comprehensively and bidirectionally probing possible causal links between such blood constituents and liability to schizophrenia are lacking.

METHODS

To disentangle putative causal links between CRP blood levels and schizophrenia in both directions, we conducted multiple univariable Mendelian-randomization (MR) analyses, ranging from fixed-effect to inverse variance-weighted (IVW), weighted-median, MR Egger and generalized summary-data-based Mendelian-randomization (GSMR) models. To prioritize metabolic risk factors for schizophrenia, a novel multivariable approach was applied: multivariable Mendelian-randomization-Bayesian model averaging (MR-BMA).

RESULTS

All forward univariable MR analyses consistently showed that CRP has a protective effect on schizophrenia, whereas reverse MR analyses consistently suggested absent causal effects of schizophrenia liability on CRP blood levels. Using MR-BMA, as the top protective factors for schizophrenia we prioritized leucine and as the prime risk-factor triglycerides in medium very-low-density lipoprotein (VLDL). The five best-performing MR-BMA models provided one additional risk factor: triglycerides in large VLDL; and two additional protective factors: citrate and lactate.

CONCLUSIONS

Our results add to a growing body of literature hinting at metabolic changes-in particular of triglycerides-independently of medication status in schizophrenia. We also highlight the absent effects of genetic liability to schizophrenia on CRP levels.

Placebo response rates and potential modifiers in double-blind randomized controlled trials of second and newer generation antidepressants for major depressive disorder in children and adolescents: a systematic review and meta-regression analysis

Children and adolescents with major depressive disorder (MDD) appear to be more responsive to placebo than adults in randomized placebo-controlled trials (RCTs) of second and newer generation antidepressants (SNG-AD). Previous meta-analyses obtained conflicting results regarding modifiers. We aimed to conduct a meta-analytical evaluation of placebo response rates based on both clinician-rating and self-rating scales. Based on the most recent and comprehensive study on adult data, we tested whether the placebo response rates in children and adolescents with MDD also increase with study duration and number of study sites. We searched systematically for published RCTs of SNG-AD in children and/or adolescents (last update: September 2017) in public domain electronic databases and additionally for documented studies in clinical trial databases. The log-transformed odds of placebo response were meta-analytically analyzed. The primary and secondary outcomes were placebo response rates at the end of treatment based on clinician-rating and self-rating scales, respectively. To examine the impact of study duration and number of study sites on placebo response rates, we performed simple meta-regression analyses. We selected other potential modifiers of placebo response based on significance in at least one previous pediatric meta-analysis and on theoretical considerations to perform explorative analyses. We applied sensitivity analyses with placebo response rates closest to week 8 to compare our data with those reported for adults. We identified 24 placebo-controlled trials (2229 patients in the placebo arms). The clinician-rated placebo response rates ranged from 22 to 62% with a pooled response rate of 45% (95% CI 41-50%). The number of study sites was a significant modifier in the simple meta-regression analysis [odds ratio (OR) 1.01, 95% CI 1.01-1.02, p = 0.0003, k = 24) with more study sites linked to a higher placebo response. Study duration was not significantly associated with the placebo response rate. The explorative simple analyses revealed that publication year may be an additional modifier. However, in the explorative multivariable analysis including the number of study sites and the publication year only the number of study sites reached a p value ≤ 0.05. The self-rated placebo response rates ranged from 1 to 68% with a pooled response rate of 26% (95% CI 10-54%) (k = 6; n = 396). This meta-analysis confirms a high pooled placebo response rate in children and adolescents based on clinician ratings, which exceeds that observed in the most recent meta-analysis of placebo effects in adults (36%; 95% CI 35-37%) published in 2016. However, and similar to findings in adults, the pooled response rates based on self-ratings were substantially lower. In accordance with previous meta-analyses, we corroborated the number of study sites as significant modifier. In comparison to the recent adult meta-analysis, the substantially lower number of pediatric studies entails a reduced power to detect modifiers. Future studies should provide more precise and homogenous information to support discovery of potential modifiers and consider no-treatment-if ethically permissible-to allow differentiation between placebo and spontaneous remission rates. If these differ, practicing clinicians should facilitate placebo effects as an addition to the verum effect to maximize benefits. Further research is required to explain the discrepant response rates between clinician and self-ratings.

A trans-ancestral meta-analysis of genome-wide association studies reveals loci associated with childhood obesity

Although hundreds of genome-wide association studies-implicated loci have been reported for adult obesity-related traits, less is known about the genetics specific for early-onset obesity and with only a few studies conducted in non-European populations to date. Searching for additional genetic variants associated with childhood obesity, we performed a trans-ancestral meta-analysis of 30 studies consisting of up to 13 005 cases (≥95th percentile of body mass index (BMI) achieved 2-18 years old) and 15 599 controls (consistently <50th percentile of BMI) of European, African, North/South American and East Asian ancestry. Suggestive loci were taken forward for replication in a sample of 1888 cases and 4689 controls from seven cohorts of European and North/South American ancestry. In addition to observing 18 previously implicated BMI or obesity loci, for both early and late onset, we uncovered one completely novel locus in this trans-ancestral analysis (nearest gene, METTL15). The variant was nominally associated with only the European subgroup analysis but had a consistent direction of effect in other ethnicities. We then utilized trans-ancestral Bayesian analysis to narrow down the location of the probable causal variant at each genome-wide significant signal. Of all the fine-mapped loci, we were able to narrow down the causative variant at four known loci to fewer than 10 single nucleotide polymorphisms (SNPs) (FAIM2, GNPDA2, MC4R and SEC16B loci). In conclusion, an ethnically diverse setting has enabled us to both identify an additional pediatric obesity locus and further fine-map existing loci.

The involvement of the canonical Wnt-signaling receptor LRP5 and LRP6 gene variants with ADHD and sexual dimorphism: Association study and meta-analysis

Wnt-signaling is one of the most abundant pathways involved in processes such as cell-proliferation, -polarity, and -differentiation. Altered Wnt-signaling has been linked with several neurodevelopmental disorders including attention-deficit/hyperactivity disorder (ADHD) as well as with cognitive functions, learning and memory. Particularly, lipoprotein receptor-related protein 5 (LRP5) or LRP6 coreceptors, responsible in the activation of the canonical Wnt-pathway, were associated with cognitive alterations in psychiatric disorders. Following the hypothesis of Wnt involvement in ADHD, we investigated the association of genetic variations in LRP5 and LRP6 genes with three independent child and adolescent ADHD (cADHD) samples (total 2,917 participants), followed by a meta-analysis including previously published data. As ADHD is more prevalent in males, we stratified the analysis according to sex and compared the results with the recent ADHD Psychiatric Genomic Consortium (PGC) GWAS. Meta-analyzing our data including previously published cADHD studies, association of LRP5 intronic rs4988319 and rs3736228 (Ala1330Val) with cADHD was observed among girls (OR = 1.80 with 95% CI = 1.07-3.02, p = .0259; and OR = 2.08 with 95% CI = 1.01-4.46, p = .0026, respectively), whereas in boys association between LRP6 rs2302685 (Val1062Ile) and cADHD was present (OR = 1.66, CI = 1.20-2.31, p = .0024). In the PGC-ADHD dataset (using pooled data of cADHD and adults) tendency of associations were observed only among females with OR = 1.09 (1.02-1.17) for LRP5 rs3736228 and OR = 1.18 (1.09-1.25) for LRP6 rs2302685. Together, our findings suggest a potential sex-specific link of cADHD with LRP5 and LRP6 gene variants, which could contribute to the differences in brain maturation alterations in ADHD affected boys and girls, and suggest possible therapy targets.

Relevance of polymorphisms in MC4R and BDNF in short normal stature

Background

Variation in genes of the leptinergic-melanocortinergic system influence both body weight and height. Because short normal stature (SNS) is characterized by reduced body height, delayed maturation and leanness, allelic variation of genes in this pathway are hypothesized to affect this common condition.

Methods

We analyzed the coding regions of LEP, MC4R, MRAP2 and BDNF in 185 children with SNS (height < 5th percentile) to search for non-synonymous and frameshift variants. For association studies (two-sided χ²-tests) population-based data sets (ExAC, EVS and KORA) were used. Cyclic AMP accumulation, cell surface expression, central expression and MAP kinase activation were assayed in vitro to determine the functional implications of identified variants.

Results

We detected eleven variants predicted to be protein-altering, four in MC4R, four in BDNF, and three in MRAP2. No variants were found in LEP. In vitro analysis implied reduced function for the MC4R variant p.Met215Ile. Loss-of-function is contrary to expectations based on obesity studies, and thus does not support that this variant is relevant for SNS. The minor SNP alleles at MC4R p.Val103Ile and BDNF p.Val66Met were nominally associated with SNS.

Conclusion

Taken together, although genes of the leptinergic-melanocortinergic system are important for normal growth, our data do not support the involvement of rare mutations in LEP, MC4R, MRAP2 or BDNF in short normal stature.

Electronic supplementary material

The online version of this article (10.1186/s12887-018-1245-1) contains supplementary material, which is available to authorized users.

The role of genetic variation of human metabolism for BMI, mental traits and mental disorders

OBJECTIVE

The aim was to assess whether loci associated with metabolic traits also have a significant role in BMI and mental traits/disorders METHODS: We first assessed the number of single nucleotide polymorphisms (SNPs) with genome-wide significance for human metabolism (NHGRI-EBI Catalog). These 516 SNPs (216 independent loci) were looked-up in genome-wide association studies for association with body mass index (BMI) and the mental traits/disorders educational attainment, neuroticism, schizophrenia, well-being, anxiety, depressive symptoms, major depressive disorder, autism-spectrum disorder, attention-deficit/hyperactivity disorder, Alzheimer's disease, bipolar disorder, aggressive behavior, and internalizing problems. A strict significance threshold of p < 6.92 × 10-6 was based on the correction for 516 SNPs and all 14 phenotypes, a second less conservative threshold (p < 9.69 × 10-5) on the correction for the 516 SNPs only.

RESULTS

19 SNPs located in nine independent loci revealed p-values < 6.92 × 10-6; the less strict criterion was met by 41 SNPs in 24 independent loci. BMI and schizophrenia showed the most pronounced genetic overlap with human metabolism with three loci each meeting the strict significance threshold. Overall, genetic variation associated with estimated glomerular filtration rate showed up frequently; single metabolite SNPs were associated with more than one phenotype. Replications in independent samples were obtained for BMI and educational attainment.

CONCLUSIONS

Approximately 5-10% of the regions involved in the regulation of blood/urine metabolite levels seem to also play a role in BMI and mental traits/disorders and related phenotypes. If validated in metabolomic studies of the respective phenotypes, the associated blood/urine metabolites may enable novel preventive and therapeutic strategies.

Effect of an vitamin D deficiency on depressive symptoms in child and adolescent psychiatric patients - a randomized controlled trial: study protocol

BACKGROUND

Depression is a significant health and economic burden worldwide affecting not only adults but also children and adolescents. Current treatment options for this group are scarce and show moderate effect sizes. There is emerging evidence that dietary patterns and specific nutritional components might play a role in the risk for developing depression. This study protocol focusses on the role of vitamin D which is for long known to be relevant for calcium and phosphorous homeostasis and bone health but might also impact on mental health. However, the assessment of the vitamin D status of depressed juvenile patients, or supplementation of vitamin D is currently not part of routine treatment. Controlled intervention studies are indispensable to prove whether a vitamin D deficiency ameliorates depressive symptoms.

METHODS/DESIGN

This double blinded, randomized controlled trial will enroll 200 inpatients from a child and adolescent psychiatric department with a vitamin D deficiency defined by a 25(OH)-vitamin D-level < 30 nmol/l (12 ng/ml) and a Beck Depressions Inventory (BDI-II) score > 13 (indicating at least: mild depression). Upon referral, all patients will be screened, checked for inclusion criteria, and those eligible will be randomized after written consent into a supplementation or placebo group. Both study-arms will receive treatment-as-usual for their psychiatric disorder according to established clinical guidelines. The participants of the vitamin D supplementation group will receive 2640 I.E. vitamin D3 q.d. for 28 days in accordance with best practice in pediatric endocrinology. We hypothesize that delaying supplementation of vitamin D in the placebo arm will affect the treatment success of the depressive symptomatology in comparison to the vitamin D supplementation group. Patients will be enrolled for a period of 28 days based on the mean length of hospitalization of juveniles with depression.

DISCUSSION

Randomized controlled trials in children and adolescents with depression are needed to elucidate the role of a vitamin D deficiency for mental disorders and to investigate the relevance of a routine assessment and supplementation of vitamin D deficits.

TRIAL REGISTRATION

DRKS00009758, 16/06/2016 (retrospectively registered).

The Effect of SH2B1 Variants on Expression of Leptin- and Insulin-Induced Pathways in Murine Hypothalamus

OBJECTIVE

We aimed to determine the effect of human SH2B1 variants on leptin and insulin signaling, major regulators of energy homeostasis, on the RNA level.

METHODS

We analyzed the expression of infrequent alleles of seven SH2B1 variants (Arg67Cys, Lys150Arg, Thr175Ala, Thr343Met, Thr484Ala, Ser616Pro and Pro689Leu) in response to insulin or leptin cell stimulation. Two of these were identified in own mutation screens, the others were predicted to be deleterious or to serve as controls. The variants were analyzed in a homologous system of mouse hypothalamic cells. Changes in expression of downstream genes were measured. Student’s t-test for independent samples was applied and effect sizes using Cohen’s d were calculated.

RESULTS

In 34 of 54 analyzed genes involved in leptin (JAK/STAT or AKT) signaling, variants nominally changed expression. The expression of three genes was considerably increased (p values ≤ 0.001: Gbp2b (67Cys; d = 25.11), Irf9 (689Leu; d = 44.65) and Isg15 (150Arg; d = 20.35)). Of 32 analyzed genes in the insulin signaling pathway, the expression of 10 genes nominally changed (p ≤ 0.05), three resulted in p values ≤ 0.01 ( Cap1 (150Arg; d = 7.48), Mapk1 (343Met; d = –6.80) and Sorbs1 (689Leu; d = 7.82)).

CONCLUSION

The increased expression of genes in leptin (JAK/STAT or AKT) signaling implies that the main mode of action for human SH2B1 mutations might affect leptin signaling rather than insulin signaling.

Eating-related Psychopathology and Food Addiction in Adolescent Psychiatric Inpatients

OBJECTIVE

Our aims were to investigate the relationship between food addiction and mental disorders including eating disorders (ED), eating-related psychopathology and body mass index-standard deviation score in a sample of adolescent psychiatric inpatients.

METHODS

Food addiction was assessed with the Yale Food Addiction Scale (YFAS). Eating-related psychopathology was measured with the Three-Factor Eating Questionnaire (TFEQ). Psychiatric diagnoses were assessed according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. The sample consisted of n = 242 adolescent psychiatric inpatients, of which n = 37 (15.3%) met criteria for an ED. Multiple regression analysis was used to examine the association between YFAS symptom count, TFEQ scales and ED controlling for age and gender.

RESULTS

Food addiction frequency was 16.5%, and the mean YFAS symptom count was 2.39 (SD: 1.60). In patients with food addiction, TFEQ scale scores were significantly higher than patients without food addiction. Frequency of ED was 42.9% in patients with and 9.9% in patients without food addiction. The TFEQ subscales disinhibition and hunger as well as diagnosis of ED were associated with YFAS symptom count.

DISCUSSION

Food addiction in adolescent psychiatric inpatients occurs with rates higher than those seen in community samples of children, adolescents and adults. Food addiction might be associated with eating styles related to susceptibility to hunger and feelings of loss of control. The implications of high-YFAS scores in restricting-type anorexia nervosa warrant further investigations to explore which and how the respective items are interpreted in this ED subgroup. Copyright © 2017 John Wiley & Sons, Ltd and Eating Disorders Association.

Decreased melanocortin-4 receptor function conferred by an infrequent variant at the human melanocortin receptor accessory protein 2 gene

OBJECTIVE

The melanocortin receptor accessory protein 2 (MRAP2) is relevant for weight regulation in mice and humans. This function is likely mediated by regulation of the melanocortin-4 receptor (MC4R). Functional implications of human MRAP2 mutations have not been described yet.

METHODS

A mutation screen was conducted in MRAP2 in 184 children and adolescents with (extreme) obesity and in 184 lean controls. Detected nonsynonymous variants were genotyped in larger independent study groups (300 people with obesity and 436 individuals with normal weight). The influence of mutant MRAP2 on MC4R signaling was analyzed in vitro.

RESULTS

(1) Three (two novel) nonsynonymous MRAP2 variants were detected: p.Ala137Thr, p.Gln174Arg, p.Arg125His (rs115655382), two synonymous variants, and three intronic variants. (2) The impact of MRAP2 on MC4R function was dependent on the ratio between the two co-expressed proteins. Increased MC4R signaling was detected at MRAP2/MC4R ratios of 2 + 1 and above. (3) The function of MC4R was reduced with the infrequent allele at the MRAP2 p.Gln174Arg variant. (4) The three nonsynonymous mutations were each only detected once among the 484 people with obesity and not among 620 individuals with normal weight.

CONCLUSIONS

This was the first study describing an effect of a MRAP2 mutation on MC4R function.

Comparative study of all Salmonella enterica serovar Enteritidis strains isolated from food and food animals in Greece from 2008 to 2010 with clinical isolates

The aim of the present work was to study the epidemiology of Salmonella enterica serovar Enteritidis (S. Enteritidis) in Greece, comparing all the food and food animal isolates during a 3-year period with clinical isolates. Submission of the generated data to the PulseNet Europe database was carried out in order to study the population structure of this particular serovar and indicate possible connections with European strains. One hundred and sixty-eight (168) S. Enteritidis strains of human, animal, and food origin, isolated during the period 2008-2010 in Greece, were studied. Strains were characterized by phenotypic (antibiotic resistance) and molecular [pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST)] methods. PFGE revealed 39 XbaI, 48 BlnI, and 80 XbaI-BlnI distinct pulsotypes, suggesting several clones circulating through the food chain and multiple sources of transmission. Submission to the PulseNet Europe database indicated that PFGE profile SENTXB.0001, the most common PFGE profile in Europe, was also predominant in Greece (33.3 %). MLST showed that all the strains studied shared the same sequence type (ST11), representing the most common ST in Europe. High rates of resistance to nalidixic acid were observed among human and poultry isolates (~25 %), indicating the potential fluoroquinolone treatment failure. Our data suggest that strains originating from multiple reservoirs circulated in Greece through the food chain during the study period. Predominant profiles in Greece were common to PulseNet Europe profiles, indicating similarities between the S. Enteritidis populations in Greece and Europe.