Marianne Giørtz Pedersen

Background: The provision of different types of mortality metrics (e.g., mortality rate ratios [MRRs] and life expectancy) allows the research community to access a more informative set of health metrics. The aim of this study was to provide a panel of mortality metrics associated with a comprehensive range of disorders and to design a web page to visualize all results. Methods and findings: In a population-based cohort of all 7,378,598 persons living in Denmark at some point between 2000 and 2018, we identified individuals diagnosed at hospitals with 1,803 specific categories of disorders through the International Classification of Diseases-10th Revision (ICD-10) in the National Patient Register. Information on date and cause of death was obtained from the Registry of Causes of Death. For each of the disorders, a panel of epidemiological and mortality metrics was estimated, including incidence rates, age-of-onset distributions, MRRs, and differences in life expectancy (estimated as life years lost [LYLs]). Additionally, we examined models that adjusted for measures of air pollution to explore potential associations with MRRs. We focus on 39 general medical conditions to simplify the presentation of results, which cover 10 broad categories: circulatory, endocrine, pulmonary, gastrointestinal, urogenital, musculoskeletal, hematologic, mental, and neurologic conditions and cancer. A total of 3,676,694 males and 3,701,904 females were followed up for 101.7 million person-years. During the 19-year follow-up period, 1,034,273 persons (14.0%) died. For 37 of the 39 selected medical conditions, mortality rates were larger and life expectancy shorter compared to the Danish general population. For these 37 disorders, MRRs ranged from 1.09 (95% confidence interval [CI]: 1.09 to 1.10) for vision problems to 7.85 (7.77 to 7.93) for chronic liver disease, while LYLs ranged from 0.31 (0.14 to 0.47) years (approximately 16 weeks) for allergy to 17.05 (16.95 to 17.15) years for chronic liver disease. Adjustment for air pollution had very little impact on the estimates; however, a limitation of the study is the possibility that the association between the different disorders and mortality could be explained by other underlying factors associated with both the disorder and mortality. Conclusions: In this study, we show estimates of incidence, age of onset, age of death, and mortality metrics (both MRRs and LYLs) for a comprehensive range of disorders. The interactive data visualization site (https://nbepi.com/atlas) allows more fine-grained analysis of the link between a range of disorders and key mortality estimates.

The Lundbeck Foundation Integrative Psychiatric Research (iPSYCH) consortium has almost doubled its Danish population-based Case–Cohort sample (iPSYCH2012). The newly updated cohort, named iPSYCH2015, expands the study base with 56,233 samples, to a combined total of 141,265 samples. The cohort is nested within the Danish population born between 1981 and 2008 and is a Case-Cohort design including 50,615 population controls. We added more cases to the existing phenotypes identified with, schizophrenia (N _new =4,131/N _total =8,113), autism (N _new =8,056 / N _total =24,975), attention-deficit/hyperactivity disorder (N _new =10,026/N _total =29,668) and affective disorder (N _new =13,999/N _total =40,482) of which a subset has bipolar affective disorder (N- _new =1,656/N _total =3,819). We also added two additional focus phenotypes, schizophrenia spectrum disorder (N=16,008) and post-partum disorder (N=3,421). In total, the expanded iPSYCH2015 sample consists of 93,608 unique individuals in the case groups and 50,615 population controls. For the sample expansion, DNA was extracted and amplified from dried blood spots samples stored within the Danish Neonatal Screening Biobank and genotyped using the Illumina Global Screening Array. The Biobank sample retrieval rate was 95%, and the genotyping success rate was 92% (97% of retrieved). We expanded the follow-up period by three years, including data such as longitudinal information on health, prescribed medicine, social and socioeconomic information.

The iPSYCH consortium has established a large Danish population-based Case-Cohort sample (iPSYCH2012) aimed at unravelling the genetic and environmental architecture of severe mental disorders. The iPSYCH2012 sample is nested within the entire Danish population born 1981-2005 including 1,472,762 persons. This paper introduces the iPSYCH2012 sample and outlines key future research directions. Cases were identified as persons with schizophrenia (N=3,540), autism (N=16,146), ADHD (N=18,726), and affective disorder (N=26,380), of which 1928 had bipolar affective disorder. Controls were randomly sampled individuals (N=30,000). Within the sample of 86,189 individuals, a total of 57,377 individuals had at least one major mental disorder. DNA was extracted from the neonatal dried blood spot samples obtained from the Danish Neonatal Screening Biobank and genotyped using the Illumina PsychChip. Genotyping was successful for 90% of the sample. The assessments of exome sequencing, methylation profiling, metabolome profiling, vitamin-D, inflammatory and neurotrophic factors are in progress. For each individual, the iPSYCH2012 sample also includes longitudinal information on health, prescribed medicine, social and socioeconomic information and analogous information among relatives. To the best of our knowledge, the iPSYCH2012 sample is the largest and most comprehensive data source for the combined study of genetic and environmental aetiologies of severe mental disorders.

The association between low birth weight and schizophrenia has been suggested by many studies. Small for gestational age (SGA) is a measure used as a proxy for intrauterine growth restriction. We aim to examine if children who are born SGA are at increased risk of developing schizophrenia and whether an association may be explained by factors shared among siblings. We linked 3 population-based registers: the Danish National Medical Birth Register, the Danish Psychiatric Central Register, and the Danish Civil Registration register to identify all persons born between 1978 and 2000. A nested case-control study and a case-sibling study design were used. There were 4650 cases of schizophrenia. Incidence rate ratios (IRRs) were estimated using conditional logistic regression. SGA was defined as the lowest 10th birth weight percentile for a given sex and gestational age. SGA was associated with an IRR of 1.23 (95% CI: 1.11–1.37) for schizophrenia in the case-control study. An IRR of 1.28 (95% CI: 0.97–1.68) was found in the case-sibling study. There is a modest association between SGA and schizophrenia. Our results indicate that this association is due to an independent effect of factors associated with low birth weight for gestational age per se, rather than other factors shared by siblings.

Introduction Reorganization of psychiatric treatment in Denmark involved a declining number of psychiatric long-stay beds and an increasing number of psychiatric supported housing facilities in the community. Very few studies have focused on the population in such facilities. Methods Information was generated combining addresses of supported psychiatric housing facilities with information from the Danish Civil Registration System to create a case register of persons living in supported psychiatric housing facilities. Through linkage with the Danish Psychiatric Central Register, we examined predictors of becoming a resident in a psychiatric housing facility, use of psychiatric services around the time of entrance to a supported psychiatric housing facility, and mortality rates for residents in a psychiatric housing facility compared to non-residents and to persons in the general population who never experienced a psychiatric admission. Results We identified schizophrenia as the strongest diagnostic predictor of becoming a resident in a supported psychiatric housing facility, followed by organic mental disorders, substance abuse, and affective disorder. In addition, the higher the number of psychiatric bed days, the higher the risk. Compared to the years before the first entrance to a supported psychiatric housing facility, the number of bed days in the year following the first entrance dropped more among residents than among comparable psychiatric patients. Mortality rates were slightly higher among residents in a supported psychiatric housing facility than among comparable psychiatric patients, but more than tenfold higher when compared to the general population of Danes. Conclusion The vast majority of persons who became residents in supported psychiatric housing facilities had previously been diagnosed with schizophrenia, schizophrenia-like disorders, and organic mental disorders, and a large proportion had substance abuse and a high use of bed days. Moving into such a facility reduced the number of bed days.