A CLEC16A variant confers risk for juvenile idiopathic arthritis and anti-cyclic citrullinated peptide antibody negative rheumatoid arthritis

Objective Variants in CLEC16A have conferred susceptibility to autoimmune diseases in genome-wide association studies. The present work aimed to investigate the locus' involvements in juvenile idiopathic arthritis (JIA) and further explore the association with rheumatoid arthritis (RA), type 1 diabetes (T1D) and Addison's disease (AD) in the Norwegian population. Methods Three single nucleotide polymorphisms (SNPs) were genotyped in patients with RA (n=809), JIA (n=509), T1D (n=1211) and AD (n=414) and in healthy controls (n=2149). Results All diseases were associated with CLEC16A, but with different SNPs. The intron 22 SNP, rs6498169, was associated with RA (p=0.006) and JIA (p=0.016) and the intron 19 SNPs, rs12708716/rs12917716, with T1D (p=1×10−5) and AD (p=2×10−4). The RA association was confined to the anti-cyclic citrullinated peptide antibody (anti-CCP) negative subgroup (p=2×10−4). Conclusion This is the first report of a CLEC16A association with JIA and a split of the RA association according to anti-CCP status. Different causative variants underlie the rheumatic versus the organ specific diseases

Maternal microchimerism in cord blood and risk of childhood-onset type 1 diabetes

Background Maternal microchimerism (MMc), the transmission of small quantities of maternal cells to the fetus, is relatively common and persistent. MMc has been detected with increased frequency in the circulation and pancreas of type 1 diabetes (T1D) patients. We investigated for the first time whether MMc levels at birth predict future T1D risk. We also tested whether cord blood MMc predicted MMc in samples taken at T1D diagnosis. Methods Participants in the Norwegian Mother and Child Cohort study were human leukocyte antigen (HLA) class II typed to determine non‐inherited, non‐shared maternal alleles (NIMA). Droplet digital (dd) polymerase chain reaction (PCR) assays specific for common HLA class II NIMA (HLADQB1*03:01, *04:02, and *06:02/03) were developed and validated. MMc was estimated as maternal DNA quantity in the fetal circulation, by NIMA specific ddPCR, measured in cord blood DNA from 71 children who later developed T1D and 126 controls within the cohort. Results We found detectable quantities of MMc in 34/71 future T1D cases (48%) and 53/126 controls (42%) (adjusted odds ratio [aOR] 1.27, 95% confidence interval (CI) 0.68‐2.36), and no significant difference in ranks of MMc quantities between cases and controls (Mann‐Whitney P = .46). There was a possible association in the NIMA HLA‐DQB1*03:01 subgroup with later T1D (aOR 3.89, 95%CI 1.05‐14.4). MMc in cord blood was not significantly associated with MMc at T1D diagnosis. Conclusions Our findings did not support the hypothesis that the degree of MMc in cord blood predict T1D risk. The potential subgroup association with T1D risk should be replicated in a larger cohort

Prenatal iron exposure and childhood type 1 diabetes

Acknowledgements: We are grateful to all the participating families in Norway who take part in this on-going cohort study. We thank Dr. Maria Vistnes at Diakonhjemmet Hospital, Oslo, Norway for help with cytokine assays, PM Ueland and Ø Midttun at BEVITAL, Bergen, Norway, for neopterin and KTR assay, and Kathleen Gillespie at Bristol University, UK for confirmatory HLA genotyping. The Norwegian Mother and Child Cohort Study is supported by the Norwegian Ministry of Health and Care Services and the Ministry of Education and Research, NIH/NIEHS (contract no N01-ES-75558), NIH/NINDS (grant no. 1 UO1 NS 047537-01 and grant no. 2 UO1 NS 047537-06A1). The sub-study was funded by a research grant from the Research Council of Norway. The Norwegian Childhood Diabetes Registry is financed by the South-Eastern Norway Regional Health Authority. Dr London was supported by the Intramural Research Program of the NIH, National Institute of Environmental Health Sciences. Dr Størdal was supported by an unrestricted grant from Oak Foundation, Geneva, Switzerland.Peer reviewedPublisher PD

Moving forward in microplastic research: A Norwegian perspective

Given the increasing attention on the occurrence of microplastics in the environment, and the potential envi-ronmental threats they pose, there is a need for researchers to move quickly from basic understanding to applied science that supports decision makers in finding feasible mitigation measures and solutions. At the same time, they must provide sufficient, accurate and clear information to the media, public and other relevant groups (e.g., NGOs). Key requirements include systematic and coordinated research efforts to enable evidence-based decision making and to develop efficient policy measures on all scales (national, regional and global). To achieve this, collaboration between key actors is essential and should include researchers from multiple disciplines, policy-makers, authorities, civil and industry organizations, and the public. This further requires clear and informative communication processes, and open and continuous dialogues between all actors. Cross-discipline dialogues between researchers should focus on scientific quality and harmonization, defining and accurately communi-cating the state of knowledge, and prioritization of topics that are critical for both research and policy, with the common goal to establish and update action plans for holistic benefit. In Norway, cross-sectoral collaboration has been fundamental in supporting the national strategy to address plastic pollution. Researchers, stakeholders and the environmental authorities have come together to exchange knowledge, identify knowledge gaps, and set targeted and feasible measures to tackle one of the most challenging aspects of plastic pollution: microplastic. In this article, we present a Norwegian perspective on the state of knowledge on microplastic research efforts. Norway’s involvement in international efforts to combat plastic pollution aims at serving as an example of how key actors can collaborate synergistically to share knowledge, address shortcomings, and outline ways forward to address environmental challenges.publishedVersio

Parental Smoking and Risk of Childhood-onset Type 1 Diabetes

Background: A few prospective studies suggest an association between maternal smoking during pregnancy and lower risk of type 1 diabetes. However, the role of unmeasured confounding and misclassification remains unclear. Methods: We comprehensively evaluated whether maternal smoking in pregnancy predicts lower risk of childhood-onset type 1 diabetes in two Scandinavian pregnancy cohorts (185,076 children; 689 cases) and a Norwegian register-based cohort (434,627 children; 692 cases). We measured cord blood cotinine as an objective marker of nicotine exposure during late pregnancy in 154 cases and 476 controls. We also examined paternal smoking during pregnancy, in addition to environmental tobacco smoke exposure the first 6 months of life, to clarify the role of characteristics of smokers in general. Results: In the pregnancy cohorts, maternal smoking beyond gestational week 12 was inversely associated with type 1 diabetes, pooled adjusted hazard ratio (aHR) 0.66 (95% CI = 0.51, 0.85). Similarly, in the Norwegian register-based cohort, children of mothers who still smoked at the end of pregnancy had lower risk of type 1 diabetes, aHR 0.65 (95% CI = 0.47, 0.89). Cord blood cotinine >=30 nmol/L was also associated with reduced risk of type 1 diabetes, adjusted odds ratio 0.42 (95% CI = 0.17, 1.0). We observed no associations of paternal smoking during pregnancy, or environmental tobacco smoke exposure, with childhood-onset type 1 diabetes. Conclusion: Maternal sustained smoking during pregnancy is associated with lower risk of type 1 diabetes in children. This sheds new light on the potential intrauterine environmental origins of the disease

Temporal trends in diabetic ketoacidosis at diagnosis of paediatric type 1 diabetes between 2006 and 2016: results from 13 countries in three continents

Aims/hypothesis The aim of this work was to evaluate geographical variability and trends in the prevalence of diabetic ketoacidosis (DKA), between 2006 and 2016, at the diagnosis of childhood-onset type 1 diabetes in 13 countries over three continents. Methods An international retrospective study on DKA at diagnosis of diabetes was conducted. Data on age, sex, date of diabetes diagnosis, ethnic minority status and presence of DKA at diabetes onset were obtained from Australia, Austria, Czechia, Denmark, Germany, Italy, Luxembourg, New Zealand, Norway, Slovenia, Sweden, USA and the UK (Wales). Mean prevalence was estimated for the entire period, both overall and by country, adjusted for sex and age group. Temporal trends in annual prevalence of DKA were estimated using logistic regression analysis for each country, before and after adjustment for sex, age group and ethnic minority status. Results During the study period, new-onset type 1 diabetes was diagnosed in 59,000 children (median age [interquartile range], 9.0 years [5.5–11.7]; male sex, 52.9%). The overall adjusted DKA prevalence was 29.9%, with the lowest prevalence in Sweden and Denmark and the highest in Luxembourg and Italy. The adjusted DKA prevalence significantly increased over time in Australia, Germany and the USA while it decreased in Italy. Preschool children, adolescents and children from ethnic minority groups were at highest risk of DKA at diabetes diagnosis in most countries. A significantly higher risk was also found for females in Denmark, Germany and Slovenia. Conclusions/interpretation DKA prevalence at type 1 diabetes diagnosis varied considerably across countries, albeit it was generally high and showed a slight increase between 2006 and 2016. Increased awareness of symptoms to prevent delay in diagnosis is warranted, especially in preschool children, adolescents and children from ethnic minority groups

Prediction of autoimmune diabetes and celiac disease in childhood by genes and perinatal environment: Design and initial aims of the PAGE study

Type 1 diabetes and celiac disease result from misdirected immune mediated destruction of host cells, and are among the most common chronic diseases in children. Despite changes in incidence over the past 3 decades, little is known about non-genetic risk factors (except for dietary gluten for celiac disease). Norway is among the countries in the world with the highest incidence of these two diseases. We describe here plans and study design for the PAGE study (Prediction of Autoimmune diabetes and celiac disease in childhood by Genes and perinatal Environment). PAGE is a sub-study within the Norwegian Mother and Child Cohort study, including follow-up of more than 100,000 pregnancies. Children who develop type 1 diabetes or celiac disease are identified via linkage to the Norwegian Patient Register and the Norwegian Childhood Diabetes Registry, with complementing information from questionnaires. The overall aim is to test hypotheses about potential non-genetic risk factors for type 1 diabetes and for celiac disease, with focus on factors operating early in life. In addition to a full cohort analysis of factors registered in questionnaires, we will analyse biomarkers in maternal blood plasma and cord blood plasma. Mothers and children will be genotyped for well-established susceptibility polymorphisms. Biomarkers will be analysed in cases and controls within the cohort. Factors to be tested in the full cohort include infant feeding, diet and dietary supplements in the mother during pregnancy and in the child, and use of antibiotics and non-prescription drugs. Biomarkers to be tested include 25-hydroxyvitamin D, markers of immune activation, and small metabolites (metabolomics). We will also explore the potential role of maternal cells in the fetal circulation (maternal microchimerism) in later risk of celiac disease and type 1 diabetes