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Background There have been concerns about COVID-19 vaccination safety among frail older individuals. We investigated the relationship between COVID-19 mRNA vaccination and mortality among individuals aged ≥ 70 years and whether mortality varies across four groups of health services used. Methods In this nationwide cohort study, we included 688,152 individuals aged ≥ 70 years at the start of the Norwegian vaccination campaign (December 27, 2020). We collected individual-level data from the Norwegian Emergency Preparedness Register for COVID-19. Vaccinated and unvaccinated individuals were matched (1:1 ratio) on the date of vaccination based on sociodemographic and clinical characteristics. The main outcome was all-cause mortality during 21 days after first dose of COVID-19 mRNA vaccination. Kaplan-Meier survival functions were estimated for the vaccinated and unvaccinated groups. We used Cox proportional-hazards regression to estimate hazard ratios (HRs) of death between vaccinated and unvaccinated individuals, with associated 95% confidence intervals (CIs), overall and by use of health services (none, home-based, short- and long-term nursing homes) and age group. Results Between December 27, 2020, and March 31, 2021, 420,771 older individuals (61.1%) were vaccinated against COVID-19. The Kaplan-Meier estimates based on the matched study sample showed a small absolute risk difference in all-cause mortality between vaccinated and unvaccinated individuals, with a lower mortality in the vaccinated group (overall HR 0.28 [95% CI: 0.24–0.31]). Similar results were obtained in analyses stratified by use of health services and age group. Conclusion We found no evidence of increased short-term mortality among vaccinated individuals in the older population after matching on sociodemographic and clinical characteristics affecting vaccination and mortality. publishedVersion

BackgroundSocioeconomic status in the risk of developing type 1 diabetes seems inconsistent. We investigated whether risk of childhood-onset type 1 diabetes differed by parental education or occupation in a nationwide cohort.MethodsThis cohort study included all children born in Norway from 1974 to 2013. In individually linked data from nationwide population registries following children born in Norway up to 15 years of age, we identified 4647 with newly diagnosed type 1 diabetes during 15,381,923 person-years of follow-up.ResultsChildren of mothers with a master’s degree had lower risk of type 1 diabetes than children of mothers with completed upper secondary education only: adjusted incidence rate ratio, aIRR=0.81 95% confidence interval: 0.69 - 0.95). There was no difference between upper secondary and lower secondary maternal education (aIRR=0.98, 95% confidence interval 0.89-1.08). Paternal education was not significantly associated with type 1 diabetes. While maternal elementary occupation was associated with a lower risk of type 1 diabetes, specific maternal- or paternal occupations were not.ConclusionsOur results suggested inverse U-shaped associations between maternal socioeconomic status and risk of type 1 diabetes. Non-linear associations be part of the reason why previous literature has been inconsistent.

Summary Background Diabetes prevalence is increasing in most places in the world, but prevalence is affected by both risk of developing diabetes and survival of those with diabetes. Diabetes incidence is a better metric to understand the trends in population risk of diabetes. Using a multicountry analysis, we aimed to ascertain whether the incidence of clinically diagnosed diabetes has changed over time. Methods In this multicountry data analysis, we assembled aggregated data describing trends in diagnosed total or type 2 diabetes incidence from 24 population-based data sources in 21 countries or jurisdictions. Data were from administrative sources, health insurance records, registries, and a health survey. We modelled incidence rates with Poisson regression, using age and calendar time (1995–2018) as variables, describing the effects with restricted cubic splines with six knots for age and calendar time. Findings Our data included about 22 million diabetes diagnoses from 5 billion person-years of follow-up. Data were from 19 high-income and two middle-income countries or jurisdictions. 23 data sources had data from 2010 onwards, among which 19 had a downward or stable trend, with an annual estimated change in incidence ranging from −1·1% to −10·8%. Among the four data sources with an increasing trend from 2010 onwards, the annual estimated change ranged from 0·9% to 5·6%. The findings were robust to sensitivity analyses excluding data sources in which the data quality was lower and were consistent in analyses stratified by different diabetes definitions. Interpretation The incidence of diagnosed diabetes is stabilising or declining in many high-income countries. The reasons for the declines in the incidence of diagnosed diabetes warrant further investigation with appropriate data sources. Funding US Centers for Disease Control and Prevention, Diabetes Australia Research Program, and Victoria State Government Operational Infrastructure Support Program.

AimsStudies of social inequality in risk of type 1 diabetes seems inconsistent. The present review aimed to comprehensively review relevant literature and describe what has been reported on socioeconomic status or parental occupation and risk of type 1 diabetes in children.MethodsWe searched for publications between January 1, 1970, and November 30, 2021. We focused on the most recent and/or informative publication in case of multiple publications from the same data source and referred to these as primary studies.ResultsOur search identified 69 publications with relevant data. We identified eight primary cohort studies with individual-level data, which we considered the highest quality of evidence. Furthermore, we identified 13 primary case-control studies and 14 semi-ecological studies with area-level socioeconomic status variables which provide weaker quality of evidence. Four of eight primary cohort studies contained data on maternal education, showing non-linear associations with type 1 diabetes that were not consistent across studies. There were no consistent patterns on the association of parental occupation and childhood-onset type 1 diabetes.ConclusionsThere is a need for more high-quality studies, but the existing literature does not suggest a major and consistent role of socioeconomic status in the risk of type 1 diabetes.Novelty statement“What is already known?”- Socioeconomic status has been associated with a variety of exposures, but the influence on type 1 diabetes risk is unclear.“What this study has found?”- Our searches identified eight high-quality and several lower quality studies, mostly using socioeconomic status as a confounder. There was no consistent association between socioeconomic status and risk of childhood type 1 diabetes. No conclusions could be drawn for specific parental occupations.“What are the implications of the study?”-While there is a need for more high-quality studies, the existing literature does not suggest a major and consistent role of socioeconomic status in the risk of type 1 diabetes.

BACKGROUND: Diabetes is a major public health issue. Because lifetime risk, life expectancy, and years of life lost are meaningful metrics for clinical decision making, we aimed to estimate these measures for type 2 diabetes in the high-income setting.; METHODS: For this multinational, population-based study, we sourced data from 24 databases for 23 jurisdictions (either whole countries or regions of a country): Australia; Austria; Canada; Denmark; Finland; France; Germany; Hong Kong; Hungary; Israel; Italy; Japan; Latvia; Lithuania; the Netherlands; Norway; Scotland; Singapore; South Korea; Spain; Taiwan; the UK; and the USA. Our main outcomes were lifetime risk of type 2 diabetes, life expectancy in people with and without type 2 diabetes, and years of life lost to type 2 diabetes. We modelled the incidence and mortality of type 2 diabetes in people with and without type 2 diabetes in sex-stratified, age-adjusted, and calendar year-adjusted Poisson models for each jurisdiction. Using incidence and mortality, we constructed life tables for people of both sexes aged 20-100 years for each jurisdiction and at two timepoints 5 years apart in the period 2005-19 where possible. Life expectancy from a given age was computed as the area under the survival curves and lifetime lost was calculated as the difference between the expected lifetime of people with versus without type 2 diabetes at a given age. Lifetime risk was calculated as the proportion of each cohort who developed type 2 diabetes between the ages of 20 years and 100 years. We estimated 95% CIs using parametric bootstrapping.; FINDINGS: Across all study cohorts from the 23 jurisdictions (total person-years 1577234194), there were 5119585 incident cases of type 2 diabetes, 4007064 deaths in those with type 2 diabetes, and 11854043 deaths in those without type 2 diabetes. The lifetime risk of type 2 diabetes ranged from 16·3% (95% CI 15·6-17·0) for Scottish women to 59·6% (58·5-60·8) for Singaporean men. Lifetime risk declined with time in 11 of the 15 jurisdictions for which two timepoints were studied. Among people with type 2 diabetes, the highest life expectancies were found for both sexes in Japan in 2017-18, where life expectancy at age 20 years was 59·2 years (95% CI 59·2-59·3) for men and 64·1 years (64·0-64·2) for women. The lowest life expectancy at age 20 years with type 2 diabetes was observed in 2013-14 in Lithuania (43·7 years [42·7-44·6]) for men and in 2010-11 in Latvia (54·2 years [53·4-54·9]) for women. Life expectancy in people with type 2 diabetes increased with time for both sexes in all jurisdictions, except for Spain and Scotland. The life expectancy gap between those with and without type 2 diabetes declined substantially in Latvia from 2010-11 to 2015-16 and in the USA from 2009-10 to 2014-15. Years of life lost to type 2 diabetes ranged from 2·5 years (Latvia; 2015-16) to 12·9 years (Israel Clalit Health Services; 2015-16) for 20-year-old men and from 3·1 years (Finland; 2011-12) to 11·2 years (Israel Clalit Health Services; 2010-11 and 2015-16) for 20-year-old women. With time, the expected number of years of life lost to type 2 diabetes decreased in some jurisdictions and increased in others. The greatest decrease in years of life lost to type 2 diabetes occurred in the USA between 2009-10 and 2014-15 for 20-year-old men (a decrease of 2·7 years).; INTERPRETATION: Despite declining lifetime risk and improvements in life expectancy for those with type 2 diabetes in many high-income jurisdictions, the burden of type 2 diabetes remains substantial. Public health strategies might benefit from tailored approaches to continue to improve health outcomes for people with diabetes.; FUNDING: US Centers for Disease Control and Prevention and Diabetes Australia. Copyright © 2022 Elsevier Ltd. All rights reserved.

Aims We investigated the current extent of undiagnosed diabetes and prediabetes and their associated cardiovascular risk profile in a population-based study. Methods All residents aged ≥20 years in the Nord-Trøndelag region, Norway, were invited to the HUNT4 Survey in 2017–2019, and 54% attended. Diagnosed diabetes was self-reported, and in those reporting no diabetes HbA1c was used to classify undiagnosed diabetes (≥48 mmol/mol [6.5%]) and prediabetes (39–47 mmol/mol [5.7%–6.4%]). We estimated the age- and sex-standardized prevalence of these conditions and their age- and sex-adjusted associations with other cardiovascular risk factors. Results Among 52,856 participants, the prevalence of diabetes was 6.0% (95% CI 5.8, 6.2), of which 11.1% were previously undiagnosed (95% CI 10.1, 12.2). The prevalence of prediabetes was 6.4% (95% CI 6.2, 6.6). Among participants with undiagnosed diabetes, 58% had HbA1c of 48–53 mmol/mol (6.5%–7.0%), and only 14% (i.e., 0.1% of the total study population) had HbA1c >64 mmol/mol (8.0%). Compared with normoglycaemic participants, those with undiagnosed diabetes or prediabetes had higher body mass index, waist circumference, systolic blood pressure, triglycerides and C-reactive protein but lower low-density lipoprotein cholesterol (all p < 0.001). Participants with undiagnosed diabetes had less favourable values for every measured risk factor compared with those with diagnosed diabetes. Conclusions The low prevalence of undiagnosed diabetes suggests that the current case-finding-based diagnostic practice is well-functioning. Few participants with undiagnosed diabetes had very high HbA1c levels indicating severe hyperglycaemia. Nonetheless, participants with undiagnosed diabetes had a poorer cardiovascular risk profile compared with participants with known or no diabetes.

Population-level trends in mortality among people with diabetes are inadequately described. We aimed to examine the magnitude and trends in excess all-cause mortality in people with diabetes.In this retrospective, multicountry analysis, we collected aggregate data from 19 data sources in 16 high-income countries or jurisdictions (in six data sources in Asia, eight in Europe, one from Australia, and four from North America) for the period from Jan 1, 1995, to Dec 31, 2016, (or a subset of this period) on all-cause mortality in people with diagnosed total or type 2 diabetes. We collected data from administrative sources, health insurance records, registries, and a health survey. We estimated excess mortality using the standardised mortality ratio (SMR).In our dataset, there were approximately 21 million deaths during 0·5 billion person-years of follow-up among people with diagnosed diabetes. 17 of 19 data sources showed decreases in the age-standardised and sex-standardised mortality in people with diabetes, among which the annual percentage change in mortality ranged from -0·5% (95% CI -0·7 to -0·3) in Hungary to -4·2% (-4·3 to -4·1) in Hong Kong. The largest decreases in mortality were observed in east and southeast Asia, with a change of -4·2% (95% CI -4·3 to -4·1) in Hong Kong, -4·0% (-4·8 to -3·2) in South Korea, -3·5% (-4·0 to -3·0) in Taiwan, and -3·6% (-4·2 to -2·9) in Singapore. The annual estimated change in SMR between people with and without diabetes ranged from -3·0% (95% CI -3·0 to -2·9; US Medicare) to 1·6% (1·4 to 1·7; Lombardy, Italy). Among the 17 data sources with decreasing mortality among people with diabetes, we found a significant SMR increase in five data sources, no significant SMR change in four data sources, and a significant SMR decrease in eight data sources.All-cause mortality in diabetes has decreased in most of the high-income countries we assessed. In eight of 19 data sources analysed, mortality decreased more rapidly in people with diabetes than in those without diabetes. Further longevity gains will require continued improvement in prevention and management of diabetes.US Centers for Disease Control and Prevention, Diabetes Australia Research Program, and Victoria State Government Operational Infrastructure Support Program.

ObjectiveTo determine risk factors for SARS-CoV-2 infection and hospitalisation among children and adolescents.DesignNationwide, population-based cohort study. Setting: Norway from 1 March 2020 to 31 April 2021. Participants: All Norwegian residents Main outcome measuresPopulation-based health care and population registries were used to study risk factors for SARS-CoV-2 infection, including socioeconomic factors, country of origin, and pre-existing chronic comorbidities. All residents were followed until age 18, emigration, death, or end of follow-up. Hazard ratios (HR) estimated by Cox regression models were adjusted for testing frequency. Further, risk factors for admission to the hospital among the infected were investigated.ResultsOf 1 182 796 residents, 22608 (1.9%) tested positive by polymerase chain reaction or lateral flow tests, of whom 107 (0.5%) were admitted to a hospital. Low family income (aHR 1.40, 95% confidence interval 1.36 to 1.46), crowded housing (1.35, 1.30 to 1.39), household size, age, and area of living were independent risk factors for infection. A non-Nordic country of origin was the strongest risk factor (aHR 2.37, 95% CI 2.30 to 2.49), whereas chronic comorbidity was not associated with the risk of infection. Chronic comorbidity was associated with hospitalisation (aHR 4.15, 2.63 to 6.56), in addition to age, whereas socioeconomic status and country of origin did not predict hospitalisation among those infected.ConclusionsSocioeconomic factors, country of origin, and area of living were associated with the risk of SARS-CoV-2 infection. However, these factors did not predict hospitalisation among those infected. Chronic comorbidity was associated with the risk of admission but not with the overall risk of acquiring SARS-CoV-2.What is already known on this topicHospital admissions rates for covid-19 among children and adolescents are low compared to adults. Admission rates to hospitals and intensive care units for covid-19 have been higher in minority groups and in children and adolescents with chronic comorbidity.Whether underlying differences in susceptibility for severe disease or the incidence of infections are driving these associations have not been investigated.What this study addsLow family income, crowded housing and household size, and country of origin outside the Nordic countries were associated with increased risk of infection with SARS-CoV-2.None of these factors, but chronic comorbidities, were associated with the risk of hospital admission among those infected.

Introduction We aimed to investigate whether the proportion of undiagnosed diabetes varies by socioeconomic status and healthcare consumption, in a Norwegian population screened with glycated hemoglobin (HbA1c). Research design and methods In this cohort study, we studied age-standardized diabetes prevalence using data from men and women aged 40–89 years participating in four surveys of the Tromsø Study with available data on HbA1c and self-reported diabetes: 1994–1995 (n=6720), 2001 (n=5831), 2007–2008 (n=11 987), and 2015–2016 (n=20 170). We defined undiagnosed diabetes as HbA1c ≥6.5% (48 mmol/mol) and no self-reported diabetes. We studied the association of education, income and contact with a general practitioner on undiagnosed diabetes and estimated adjusted prevalence ratio (aPR) from multivariable adjusted (age, sex, body mass index) log-binomial regression. Results Higher education was associated with lower prevalence of diagnosed and undiagnosed diabetes. Those with secondary and tertiary education had lower prevalence of undiagnosed diabetes (aPR for tertiary vs primary: 0.54, 95% CI: 0.44 to 0.66). Undiagnosed as a proportion of all diabetes was also significantly lower in those with tertiary education (aPR:0.78, 95% CI: 0.65 to 0.93). Household income was also negatively associated with prevalence of undiagnosed diabetes. Across the surveys, approximately 80% of those with undiagnosed diabetes had been in contact with a general practitioner the last year, similar to those without diabetes. Conclusions Undiagnosed diabetes was lower among participants with higher education. The hypothesis that those with undiagnosed diabetes had been less in contact with a general practitioner was not supported.

Some studies have suggested a declining mortality in type 1 diabetes, but it is unclear if the pattern of mortality trends differs by country and age group, and how mortality trends in type 1 diabetes relate to trends in the general population mortality. We assembled aggregated data on all-cause mortality in people with type 1 diabetes by 5-year age group and sex between 2000 and 2016 from an international diabetes consortium database, GLOBODIAB. Data were from administrative sources, health insurance records and registries. We used joinpoint regression analysis to examine trends in annual mortality rates (standardized to the 2010 European Union population) and mortality rate ratios (MRRs) (relative to the mortality in people without diabetes) in all age groups, and stratified by age ( In conclusion, all-cause mortality in type 1 diabetes has declined in recent years in the majority of data sources, but remains considerably higher than in the nondiabetic population. These data highlight that there is still scope to improve mortality in type 1 diabetes and reduce inequalities within and between populations. Disclosure P. Lopez-doriga ruiz: None. G. A. Nichols: Research Support; Self; Boehringer Ingelheim International GmbH, Bristol-Myers Squibb Company, National Institute of Diabetes and Digestive and Kidney Diseases. S. Pildava: None. S. H. Read: Employee; Self; Certara. S. Wild: Advisory Panel; Self; Gilead Sciences, Inc., Other Relationship; Self; Novo Nordisk. J. E. Shaw: Advisory Panel; Self; Eli Lilly and Company, Merck Sharp & Dohme Corp., Pfizer Inc., Research Support; Self; AstraZeneca, Speaker’s Bureau; Self; AstraZeneca, Eli Lilly and Company, Novo Nordisk. D. J. Magliano: None. L. Chen: None. J. I. Morton: None. A. Salim: None. B. Carstensen: Stock/Shareholder; Self; Novo Nordisk. E. W. Gregg: None. M. E. Pavkov: None. M. Mata-cases: Consultant; Self; Mundipharma International, Speaker’s Bureau; Self; Boehringer Ingelheim Pharmaceuticals, Inc., MSD Corporation, Novo Nordisk. D. Mauricio: None. Funding Centers for Disease Control and Prevention

Objective To assess rates of cardiovascular and haemostatic events in the first 28 days after vaccination with the Oxford-AstraZeneca vaccine ChAdOx1-S in Denmark and Norway and to compare them with rates observed in the general populations. Design Population based cohort study. Setting Nationwide healthcare registers in Denmark and Norway. Participants All people aged 18-65 years who received a first vaccination with ChAdOx1-S from 9 February 2021 to 11 March 2021. The general populations of Denmark (2016-18) and Norway (2018-19) served as comparator cohorts. Main outcome measures Observed 28 day rates of hospital contacts for incident arterial events, venous thromboembolism, thrombocytopenia/coagulation disorders, and bleeding among vaccinated people compared with expected rates, based on national age and sex specific background rates from the general populations of the two countries. Results The vaccinated cohorts comprised 148 792 people in Denmark (median age 45 years, 80% women) and 132 472 in Norway (median age 44 years, 78% women), who received their first dose of ChAdOx1-S. Among 281 264 people who received ChAdOx1-S, the standardised morbidity ratio for arterial events was 0.97 (95% confidence interval 0.77 to 1.20). 59 venous thromboembolic events were observed in the vaccinated cohort compared with 30 expected based on the incidence rates in the general population, corresponding to a standardised morbidity ratio of 1.97 (1.50 to 2.54) and 11 (5.6 to 17.0) excess events per 100 000 vaccinations. A higher than expected rate of cerebral venous thrombosis was observed: standardised morbidity ratio 20.25 (8.14 to 41.73); an excess of 2.5 (0.9 to 5.2) events per 100 000 vaccinations. The standardised morbidity ratio for any thrombocytopenia/coagulation disorders was 1.52 (0.97 to 2.25) and for any bleeding was 1.23 (0.97 to 1.55). 15 deaths were observed in the vaccine cohort compared with 44 expected. Conclusions Among recipients of ChAdOx1-S, increased rates of venous thromboembolic events, including cerebral venous thrombosis, were observed. For the remaining safety outcomes, results were largely reassuring, with slightly higher rates of thrombocytopenia/coagulation disorders and bleeding, which could be influenced by increased surveillance of vaccine recipients. The absolute risks of venous thromboembolic events were, however, small, and the findings should be interpreted in the light of the proven beneficial effects of the vaccine, the context of the given country, and the limitations to the generalisability of the study findings.

Background There is limited evidence linking type 2 diabetes (T2D) to influenza-related complications. Objectives To test a set of research questions relating to pandemic influenza vaccination, hospitalization and mortality in people with and without T2D. Methods In this population-based cohort study, we linked individual-level data from several national registers for all Norwegian residents aged 30 years or more as of January 2009. People with or without T2D at baseline (n = 2 992 228) were followed until December 2013. We used Cox regression to estimate adjusted hazard ratios (aHRs). Results Pandemic influenza hospitalization was more common in individuals with T2D (aHR = 2.46, 95% CI 2.04-2.98). The mortality hazard ratio associated with hospitalization for pandemic influenza was lower in people with T2D (aHR = 1.82, 95% CI 1.21-2.74) than in those without T2D (aHR = 3.89, 95% CI 3.27-4.62). The same pattern was observed when restricting to 90-day mortality (aHR = 3.89, 95% CI 1.25-12.06 amongst those with T2D and aHR = 10.79, 95% CI 7.23-16.10 amongst those without T2D). The rate of hospitalization for pandemic influenza was 78% lower in those vaccinated compared to nonvaccinated amongst people with T2D (aHR = 0.22, 95% CI 0.11-0.39), whilst the corresponding estimate for those without T2D was 59% lower (aHR = 0.41, 95% CI 0.33-0.52). Mortality was 25% lower in those vaccinated compared to nonvaccinated amongst people with T2D (aHR = 0.75, 95% CI 0.73-0.77), whilst the corresponding estimate for those without T2D was 9% (aHR = 0.91, 95% CI 0.90-0.92). Conclusions There may have been a lower threshold for pandemic influenza hospitalization for people with T2D, rather than more severe influenza infection. Our combined results support the importance of influenza vaccination amongst people with T2D, especially during pandemics.

To provide up-to-date estimates of undiagnosed diabetes mellitus (UDM) prevalence - both globally, and by region/country, for the year 2021.Data sources reporting diabetes prevalence were identified through a systematic search in the peer-reviewed and grey literature. The prevalence of undiagnosed diabetes was estimated from the data from each country where data was available. For countries without in-country data, the prevalence of undiagnosed diabetes was approximated by extrapolating the average of the estimates from countries with data sources within the same International Diabetes Federation (IDF) region and World Bank income grouping. We then applied these stratified prevalence estimates of UDM from each country to the number of adults in each strata and summed the counts to generate the number of adults with UDM (aged 20-79 years) for 215 countries and territories.In 2021, almost one in two adults (20-79 years old) with diabetes were unaware of their diabetes status (44.7%; 239.7 million). The highest proportions of undiagnosed diabetes (53.6%) were found in the Africa, Western Pacific (52.8%) and South-East Asia regions (51.3%), respectively. The lowest proportion of undiagnosed diabetes was observed in North America and the Caribbean (24.2%).Diabetes surveillance needs to be strengthened to reduce the prevalence of UDM, particularly in low- and middle-income countries.

Aims/hypothesis This study aimed to examine recent time trends in the incidence and prevalence of type 2 diabetes in Norway. Methods In this Norwegian nationwide cohort study, we linked data from national registries with prospectively collected data on diabetes medication and diabetes diagnoses for all residents in Norway aged 30 to 89 years (>3.2 million people). We analysed trends in incidence and prevalence of type 2 diabetes from 2009 to 2014 by type of treatment, sex, age, education level and place of birth. Results During 15,463,691 person-years of follow-up from 2009 to 2014, we identified 75,496 individuals with new-onset type 2 diabetes. Of these, 36,334 (48%) were treated with blood-glucose-lowering drugs within 6 months of diagnosis. A low education level and being born in Asia, Africa or South America were significant risk factors for incident type 2 diabetes. While the prevalence of type 2 diabetes increased from 4.9% to 6.1% during the study period, the incidence decreased significantly from 609 cases per 100,000 person-years in 2009 to 398 cases per 100,000 in 2014, an annual reduction of 10.1% (95% CI −10.5, −9.6). A declining incidence was seen for both pharmacologically and non-pharmacologically treated type 2 diabetes, and in all subgroups defined by sex, age group, education level and place of birth. Conclusions/interpretations This nationwide study shows that, despite a decreasing incidence of type 2 diabetes in Norway, the prevalence continues to rise, probably due to diagnosis at a younger age and increased longevity. Electronic supplementary material The online version of this article (10.1007/s00125-018-4681-4) contains peer-reviewed but unedited supplementary material, which is available to authorised users.

Aims/hypothesis Case reports have linked influenza infections to the development of type 1 diabetes. We investigated whether pandemic and seasonal influenza infections were associated with subsequent increased risk of type 1 diabetes. Methods In this population-based registry study, we linked individual-level data from national health registries for the entire Norwegian population under the age of 30 years for the years 2006–2014 (2.5 million individuals). Data were obtained from the National Registry (population data), the Norwegian Patient Registry (data on inpatient and outpatient specialist care), the Primary Care Database, the Norwegian Prescription Database and the Norwegian Surveillance System for Communicable Diseases. Pandemic influenza was defined as either a clinical influenza diagnosis during the main pandemic period or a laboratory-confirmed test. Seasonal influenza was defined by a clinical diagnosis of influenza between 2006 and 2014. We used Cox regression to estimate HRs for new-onset type 1 diabetes after an influenza infection, adjusted for year of birth, sex, place of birth and education. Results The adjusted HR for type 1 diabetes after pandemic influenza infection was 1.19 (95% CI 0.97, 1.46). In the subgroup with laboratory-confirmed influenza A (H1N1), influenza was associated with a twofold higher risk of subsequent type 1 diabetes before age 30 years (adjusted HR: 2.26, 95% CI 1.51, 3.38). Conclusions/interpretation Overall, we could not demonstrate a clear association between clinically reported pandemic influenza infection and incident type 1 diabetes. However, we found a twofold excess of incident diabetes in the subgroup with laboratory-confirmed pandemic influenza A (H1N1). Electronic supplementary material The online version of this article (10.1007/s00125-018-4662-7) contains peer-reviewed but unedited supplementary material, which is available to authorised users.

To the Editor:Given the association between the 2009 pandemic influenza A H1N1 vaccination and narcolepsy,1 it is of interest to study other human leukocyte antigen (HLA)–associated autoimmune diseases such as type 1 diabetes. While an analysis from Stockholm did not show any association with type 1