International benchmarking in type 1 diabetes: Large difference in childhood HbA1c between 8 high-income countries but similar rise during adolescence -A quality registry study Short running title: Similar HbA1c pattern between countries

Conclusions: Worse glycaemic control was found in adolescent females, and they had a higher frequency of microvascular complications. Improved paediatric diabetes care is of great importance for increasing the likelihood of lower mortality and morbidity later in life.

INTRODUCTION: Collagenous gastritis (CG), a rare disorder of unknown etiology, has been postulated to have immune-mediated mechanisms. We investigated (i) the incidence and prevalence of CG in a pediatric population; (ii) the clinical, endoscopic, and histologic characteristics of childhood-onset CG; and (iii) the evidence for autoimmunity and/or inflammatory activity in these patients. METHODS: Clinical, endoscopic, and histologic data were reviewed longitudinally in a population-based Swedish cohort of 15 patients with childhood-onset CG diagnosed in the period 2008–2019. A set of 11 autoantibodies, 4 blood inflammatory biomarkers, and the human leukocyte antigen DQ2/DQ8 genotype was analyzed cross-sectionally. RESULTS: The incidence rate of childhood-onset CG was 0.25/100,000 person-years, with an incidence rate ratio of girls to boys of 4.2 (95% confidence interval, 1.2–15). The prevalence of CG was 2.1/100,000 in children aged younger than 18 years. The endoscopic and histologic findings remained pathologic in all the examined patients during a median follow-up of 4.4 years. Many patients had heredity for autoimmune disorders (47%) and/or tested positive for autoantibodies (40%) or human leukocyte antigen DQ2/DQ8 (53%). No associated autoimmune comorbidities were observed. The serum levels of calprotectin and amyloid A were increased in 10/15 (67%) and 5/15 (33%) of the patients, respectively, whereas plasma C-reactive protein levels were normal in all, but 1 patient. DISCUSSION: The results indicate that childhood-onset CG is rare and has a chronic disease course. Although signs of autoimmune predisposition are frequent, early development of autoimmune comorbidities seems seldom. Serum calprotectin and amyloid A represent novel candidate biomarkers of inflammatory activity in CG (see Visual Abstract, Supplementary Digital Content 4, http://links.lww.com/CTG/A349 ).

Conclusions: Worse glycaemic control was found in adolescent females, and they had a higher frequency of microvascular complications. Improved paediatric diabetes care is of great importance for increasing the likelihood of lower mortality and morbidity later in life.

Aim To evaluate whether a very low glycated haemoglobin A (HbA1c) (<48 mmol/mol, 6.5%) during childhood compared to higher HbA1c values further decreases the risk for microvascular complications. Methods Data were included from the 5116 patients with type 1 diabetes transferred from the Swedish paediatric diabetes quality registry to the Swedish National Diabetes Register (NDR), until 2014. All HbA1c values ever registered in the paediatric registry were used to divide patients into six groups based on the mean HbA1c. Values were compared with HbA1c registered in 2013 and 2014 in NDR, together with data on retinopathy, micro‐ and macroalbuminuria, age at onset and duration of diabetes. Results The group with lowest mean‐HbA1c during childhood had also the lowest mean as young adults during 2013 and 2014. The most common complication as young adults was retinopathy. The proportion with macroalbuminuria was 3% in the lowest HbA1c group during childhood and 3.9% in the highest group, and lower in the groups in between. Microalbuminuria had the same pattern. Retinopathy increased with each HbA1c group. Conclusion Children with the lowest HbA1c values had the lowest HbA1c values as adults. HbA1c was associated with retinopathy but the relationship with albuminuria was not obvious.