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

BACKGROUND: Psychiatric disorders and type 2 diabetes mellitus (T2DM) are heritable, polygenic, and often comorbid conditions, yet knowledge about their potential shared familial risk is lacking. We used family designs and T2DM polygenic risk score (T2DM-PRS) to investigate the genetic associations between psychiatric disorders and T2DM. METHODS: We linked 659 906 individuals born in Denmark 1990-2000 to their parents, grandparents, and aunts/uncles using population-based registers. We compared rates of T2DM in relatives of children with and without a diagnosis of any or one of 11 specific psychiatric disorders, including neuropsychiatric and neurodevelopmental disorders, using Cox regression. In a genotyped sample (iPSYCH2015) of individuals born 1981-2008 (n = 134 403), we used logistic regression to estimate associations between a T2DM-PRS and these psychiatric disorders. RESULTS: Among 5 235 300 relative pairs, relatives of individuals with a psychiatric disorder had an increased risk for T2DM with stronger associations for closer relatives (parents:hazard ratio = 1.38, 95% confidence interval 1.35-1.42; grandparents: 1.14, 1.13-1.15; and aunts/uncles: 1.19, 1.16-1.22). In the genetic sample, one standard deviation increase in T2DM-PRS was associated with an increased risk for any psychiatric disorder (odds ratio = 1.11, 1.08-1.14). Both familial T2DM and T2DM-PRS were significantly associated with seven of 11 psychiatric disorders, most strongly with attention-deficit/hyperactivity disorder and conduct disorder, and inversely with anorexia nervosa. CONCLUSIONS: Our findings of familial co-aggregation and higher T2DM polygenic liability associated with psychiatric disorders point toward shared familial risk. This suggests that part of the comorbidity is explained by shared familial risks. The underlying mechanisms still remain largely unknown and the contributions of genetics and environment need further investigation.

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

BACKGROUND: Although several types of risk factors for anorexia nervosa (AN) have been identified, including birth-related factors, somatic, and psychosocial risk factors, their interplay with genetic susceptibility remains unclear. Genetic and epidemiological interplay in AN risk were examined using data from Danish nationwide registers. AN polygenic risk score (PRS) and risk factor associations, confounding from AN PRS and/or parental psychiatric history on the association between the risk factors and AN risk, and interactions between AN PRS and each level of target risk factor on AN risk were estimated. METHODS: Participants were individuals born in Denmark between 1981 and 2008 including nationwide-representative data from the iPSYCH2015, and Danish AN cases from the Anorexia Nervosa Genetics Initiative and Eating Disorder Genetics Initiative cohorts. A total of 7003 individuals with AN and 45 229 individuals without a registered AN diagnosis were included. We included 22 AN risk factors from Danish registers. RESULTS: Risk factors showing association with PRS for AN included urbanicity, parental ages, genitourinary tract infection, and parental socioeconomic factors. Risk factors showed the expected association to AN risk, and this association was only slightly attenuated when adjusted for parental history of psychiatric disorders or/and for the AN PRS. The interaction analyses revealed a differential effect of AN PRS according to the level of the following risk factors: sex, maternal age, genitourinary tract infection, C-section, parental socioeconomic factors and psychiatric history. CONCLUSIONS: Our findings provide evidence for interactions between AN PRS and certain risk-factors, illustrating potential diverse risk pathways to AN diagnosis.

Involuntary treatment in patients with anorexia nervosa: utilization patterns and associated factors.

BACKGROUND: A subgroup of patients with anorexia nervosa (AN) undergoing involuntary treatment (IT) seems to account for most of the IT events. Little is known about these patients and their treatment including the temporal distribution of IT events and factors associated with subsequent utilization of IT. Hence, this study explores (1) utilization patterns of IT events, and (2) factors associated with subsequent utilization of IT in patients with AN. METHODS: In this nationwide Danish register-based retrospective exploratory cohort study patients were identified from their first (index) hospital admission with an AN diagnosis and followed up for 5 years. We explored data on IT events including estimated yearly and total 5-year rates, and factors associated with subsequent increased IT rates and restraint, using regression analyses and descriptive statistics. RESULTS: IT utilization peaked in the initial few years starting at or following the index admission. A small percentage (1.0%) of patients accounted for 67% of all IT events. The most frequent measures reported were mechanical and physical restraint. Factors associated with subsequent increased IT utilization were female sex, lower age, previous admissions with psychiatric disorders before index admission, and IT related to those admissions. Factors associated with subsequent restraint were lower age, previous admissions with psychiatric disorders, and IT related to these. CONCLUSIONS: High IT utilization in a small percentage of individuals with AN is concerning and can lead to adverse treatment experiences. Exploring alternative approaches to treatment that reduce the need for IT is an important focus for future research.

The Eating Disorders Genetics Initiative (EDGI): study protocol.

BACKGROUND: The Eating Disorders Genetics Initiative (EDGI) is an international investigation exploring the role of genes and environment in anorexia nervosa, bulimia nervosa, and binge-eating disorder. METHODS: A total of 14,500 individuals with eating disorders and 1500 controls will be included from the United States (US), Australia (AU), New Zealand (NZ), and Denmark (DK). In the US, AU, and NZ, participants will complete comprehensive online phenotyping and will submit a saliva sample for genotyping. In DK, individuals with eating disorders will be identified by the National Patient Register, and genotyping will occur using bloodspots archived from birth. A genome-wide association study will be conducted within EDGI and via meta-analysis with other data from the Eating Disorders Working Group of the Psychiatric Genomics Consortium (PGC-ED). DISCUSSION: EDGI represents the largest genetic study of eating disorders ever to be conducted and is designed to rapidly advance the study of the genetics of the three major eating disorders (anorexia nervosa, bulimia nervosa, and binge-eating disorder). We will explicate the genetic architecture of eating disorders relative to each other and to other psychiatric and metabolic disorders and traits. Our goal is for EDGI to deliver "actionable" findings that can be transformed into clinically meaningful insights. TRIAL REGISTRATION: EDGI is a registered clinical trial: clinicaltrials.gov NCT04378101 .

Association and Familial Coaggregation of Type 1 Diabetes and Eating Disorders: A Register-Based Cohort Study in Denmark and Sweden.

OBJECTIVE: To ascertain the association and coaggregation of eating disorders and childhood-onset type 1 diabetes in families. RESEARCH DESIGN AND METHODS: Using population samples from national registers in Sweden (n = 2,517,277) and Demark (n = 1,825,920), we investigated the within-individual association between type 1 diabetes and eating disorders and their familial coaggregation among full siblings, half siblings, full cousins, and half cousins. On the basis of clinical diagnoses, we classified eating disorders into any eating disorder (AED), anorexia nervosa (AN) and atypical AN, and other eating disorder (OED). Associations were determined with hazard ratios (HRs) with 95% CIs from Cox regressions. RESULTS: Swedish and Danish individuals with a type 1 diabetes diagnosis had a greater risk of receiving an eating disorder diagnosis (HR [95% CI] Sweden: AED 2.02 [1.80-2.27], AN 1.63 [1.36-1.96], OED 2.34 [2.07-2.63]; Denmark: AED 2.19 [1.84-2.61], AN 1.78 [1.36-2.33], OED 2.65 [2.20-3.21]). We also meta-analyzed the results: AED 2.07 (1.88-2.28), AN 1.68 (1.44-1.95), OED 2.44 (2.17-2.72). There was an increased risk of receiving an eating disorder diagnosis in full siblings in the Swedish cohort (AED 1.25 [1.07-1.46], AN 1.28 [1.04-1.57], OED 1.28 [1.07-1.52]); these results were nonsignificant in the Danish cohort. CONCLUSIONS: Patients with type 1 diabetes are at a higher risk of subsequent eating disorders; however, there is conflicting support for the relationship between having a sibling with type 1 diabetes and an eating disorder diagnosis. Diabetes health care teams should be vigilant about disordered eating behaviors in children and adolescents with type 1 diabetes.

Paternal-age-related de novo mutations and risk for five disorders.

There are established associations between advanced paternal age and offspring risk for psychiatric and developmental disorders. These are commonly attributed to genetic mutations, especially de novo single nucleotide variants (dnSNVs), that accumulate with increasing paternal age. However, the actual magnitude of risk from such mutations in the male germline is unknown. Quantifying this risk would clarify the clinical significance of delayed paternity. Using parent-child trio whole-exome-sequencing data, we estimate the relationship between paternal-age-related dnSNVs and risk for five disorders: autism spectrum disorder (ASD), congenital heart disease, neurodevelopmental disorders with epilepsy, intellectual disability and schizophrenia (SCZ). Using Danish registry data, we investigate whether epidemiologic associations between each disorder and older fatherhood are consistent with the estimated role of dnSNVs. We find that paternal-age-related dnSNVs confer a small amount of risk for these disorders. For ASD and SCZ, epidemiologic associations with delayed paternity reflect factors that may not increase with age.

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

BACKGROUND: Genetic factors contribute to anorexia nervosa (AN); and the first genome-wide significant locus has been identified. We describe methods and procedures for the Anorexia Nervosa Genetics Initiative (ANGI), an international collaboration designed to rapidly recruit 13,000 individuals with AN and ancestrally matched controls. We present sample characteristics and the utility of an online eating disorder diagnostic questionnaire suitable for large-scale genetic and population research. METHODS: ANGI recruited from the United States (US), Australia/New Zealand (ANZ), Sweden (SE), and Denmark (DK). Recruitment was via national registers (SE, DK); treatment centers (US, ANZ, SE, DK); and social and traditional media (US, ANZ, SE). All cases had a lifetime AN diagnosis based on DSM-IV or ICD-10 criteria (excluding amenorrhea). Recruited controls had no lifetime history of disordered eating behaviors. To assess the positive and negative predictive validity of the online eating disorder questionnaire (ED100K-v1), 109 women also completed the Structured Clinical Interview for DSM-IV (SCID), Module H. RESULTS: Blood samples and clinical information were collected from 13,363 individuals with lifetime AN and from controls. Online diagnostic phenotyping was effective and efficient; the validity of the questionnaire was acceptable. CONCLUSIONS: Our multi-pronged recruitment approach was highly effective for rapid recruitment and can be used as a model for efforts by other groups. High online presence of individuals with AN rendered the Internet/social media a remarkably effective recruitment tool in some countries. ANGI has substantially augmented Psychiatric Genomics Consortium AN sample collection. ANGI is a registered clinical trial: clinicaltrials.govNCT01916538; https://clinicaltrials.gov/ct2/show/NCT01916538?cond=Anorexia+Nervosa&draw=1&rank=3.

Predicting ADHD by Assessment of Rutter's Indicators of Adversity in Infancy.

BACKGROUND: Attention-deficit/hyperactivity disorder (ADHD) is a prevalent neurodevelopmental disorder with early onset. ADHD is associated with significant morbidity and mortality, partly due to delayed diagnosis. Identification of children at high risk for developing ADHD could lead to earlier diagnosis and potentially change the negative trajectory of the illness for the better. Since early psychosocial adversity is considered to be a likely etiological risk factor for ADHD, markers of this construct may be useful for early identification of children at high risk. Therefore, we sought to investigate whether Rutter's indicators of adversity (low social class, severe marital discord, large family size, paternal criminality, maternal mental disorder, and placement in out-of-home care) assessed in infancy could serve as early predictors for the development of ADHD. METHODS AND FINDINGS: Using data from the Danish nationwide population-based registers, we established a cohort consisting of all 994,407 children born in Denmark between January 1st 1993 and December 31st 2011 and extracted dichotomous values for the six Rutter's indicators of adversity at age 0-12 months (infancy) for each cohort member. The cohort members were followed from their second birthday and the association between the sum of Rutter's indicators of adversity (RIA-score) in infancy and subsequent development of ADHD was estimated by means of Cox regression. Also, the number needed to screen (NNS) to detect one case of ADHD based on the RIA-scores in infancy was calculated. During follow-up (9.6 million person-years), 15,857 males and 5,663 females from the cohort developed ADHD. For both males and females, there was a marked dose-response relationship between RIA-scores assessed in infancy and the risk for developing ADHD. The hazard ratios for ADHD were 11.0 (95%CI: 8.2-14.7) and 11.4 (95%CI: 7.1-18.3) respectively, for males and females with RIA-scores of 5-6, compared to males and females with RIA-scores of 0. Among males with RIA-scores of 5-6, 37.6% (95%CI: 27.0-50.7) had been diagnosed with ADHD prior to the age of 20, corresponding to a NNS of 3.0 (95%CI: 2.2-4.0). CONCLUSIONS: Rutter's indicators of adversity assessed in infancy strongly predicted ADHD. This knowledge may be important for early identification of ADHD.

Autism spectrum disorder in individuals with anorexia nervosa and in their first- and second-degree relatives: Danish nationwide register-based cohort-study.

BACKGROUND: Clinical and population-based studies report increased prevalence of autism spectrum disorders (ASD) in individuals with anorexia nervosa and in their relatives. No nationwide study has yet been published on co-occurrence of these disorders. AIMS: To investigate comorbidity of ASD in individuals with anorexia nervosa, and aggregation of ASD and anorexia nervosa in their relatives. METHOD: In Danish registers we identified all individuals born in 1981-2008, their parents, and full and half siblings, and linked them to data on hospital admissions for psychiatric disorders. RESULTS: Risk of comorbidity of ASD in probands with anorexia nervosa and aggregation of ASD in families of anorexia nervosa probands were increased. However, the risk of comorbid and familial ASD did not differ significantly from comorbid and familial major depression or any psychiatric disorder in anorexia nervosa probands. CONCLUSIONS: We confirm aggregation of ASD in probands with anorexia nervosa and in their relatives; however, the relationship between anorexia nervosa and ASD appears to be non-specific.

Analysis of risk factors for schizophrenia with two different case definitions: a nationwide register-based external validation study.

Different case definitions of schizophrenia have been used in register based research. However, no previous study has externally validated two different case definitions of schizophrenia against a wide range of risk factors for schizophrenia. We investigated hazard ratios (HRs) for a wide range of risk factors for ICD-10 DCR schizophrenia using a nationwide Danish sample of 2,772,144 residents born in 1955-1997. We compared one contact only (OCO) (the case definition of schizophrenia used in Danish register based studies) with two or more contacts (TMC) (a case definition of at least 2 inpatient contacts with schizophrenia). During the follow-up, the OCO definition included 15,074 and the TMC 7562 cases; i.e. half as many. The TMC case definition appeared to select for a worse illness course. A wide range of risk factors were uniformly associated with both case definitions and only slightly higher risk estimates were found for the TMC definition. Choosing at least 2 inpatient contacts with schizophrenia (TMC) instead of the currently used case definition would result in almost similar risk estimates for many well-established risk factors. However, this would also introduce selection and include considerably fewer cases and reduce power of e.g. genetic studies based on register-diagnosed cases only.

Psychotic experiences co-occur with sleep problems, negative affect and mental disorders in preadolescence.

BACKGROUND: Knowledge on the significance of childhood psychotic symptoms and experiences (PE) is still limited. This study aimed to investigate the prevalence and clinical significance of PE in preadolescent children from the general population by use of in-depth psychopathological interviews and comprehensive diagnostic assessments. METHODS: We investigated 1,632 children from the general population-based Copenhagen Child Cohort 2000. PE were measured by semistructured interviews using the K-SADS-PL-items on psychotic and affective symptoms, each symptom scored as not present versus likely or definitely present. The Development and Well-Being Assessment (DAWBA) was used independently to diagnose DSM-IV-mental disorders. Puberty development and sleep disturbance were self-reported. The associations between PE (any lifetime hallucination and/or delusion) and various mental problems and disorders were examined by multivariable binomial regression analyses, adjusting for gender and onset of puberty. RESULTS: The weighted life time prevalence of PE at age 11-12 years was 10.9% (CI 9.1-12.7). The majority of children with PE (n = 172) either had a diagnosable DSM-IV-mental disorder (31.4%) or self-reported mental health difficulties in absence of a diagnosis (31.4%). The risk of delusions increased with onset of puberty. The risk of PE increased with emotional and neurodevelopmental disorders, subthreshold depressive symptoms, sleep problems and lack of sleep, regardless of whether PE were expressed as hallucinations and/or delusions. The highest correlations were seen for emotional and multiple disorders. CONCLUSIONS: Psychotic experiences are particularly prevalent in the context of affective dysregulation and sleep disturbance, increase with onset of puberty and represent a trans-diagnostic marker of psychopathology.