Exome sequencing of 20,791 cases of type 2 diabetes and 24,440 controls.

Protein-coding genetic variants that strongly affect disease risk can yield relevant clues to disease pathogenesis. Here we report exome-sequencing analyses of 20,791 individuals with type 2 diabetes (T2D) and 24,440 non-diabetic control participants from 5 ancestries. We identify gene-level associations of rare variants (with minor allele frequencies of less than 0.5%) in 4 genes at exome-wide significance, including a series of more than 30 SLC30A8 alleles that conveys protection against T2D, and in 12 gene sets, including those corresponding to T2D drug targets (P = 6.1 × 10-3) and candidate genes from knockout mice (P = 5.2 × 10-3). Within our study, the strongest T2D gene-level signals for rare variants explain at most 25% of the heritability of the strongest common single-variant signals, and the gene-level effect sizes of the rare variants that we observed in established T2D drug targets will require 75,000-185,000 sequenced cases to achieve exome-wide significance. We propose a method to interpret these modest rare-variant associations and to incorporate these associations into future target or gene prioritization efforts.

Heterogeneity in glycaemic control in children and adolescents with type 1 diabetes: A latent class trajectory analysis of Danish nationwide data.

AIMS: Suboptimal glycaemic control in children and adolescents with type 1 diabetes is prevalent and associated with increased risk of diabetes-related complications and mortality later in life. First, we aimed to identify distinct glycated haemoglobin (HbA1c) trajectories in children and adolescents (2-19 years) with type 1 diabetes. Second, we examined their associations with clinical and socio-demographic factors. METHODS: Data were obtained from the Danish Registry of Childhood and Adolescent Diabetes (DanDiabKids) comprising all Danish children and adolescents diagnosed with type 1 diabetes from 1996 to 2019. Subgroups of distinct mean trajectories of HbA1c were identified using data-driven latent class trajectory modelling. RESULTS: A total of 5889 children (47% female) had HbA1c measured a median of 6 times (interquartile range 3-8) and contributing to 36,504 measurements. We identified four mean HbA1c trajectories, referred to as 'Stable but elevated HbA1c' (83%), 'Increasing HbA1c' (5%), 'Late HbA1c peak' (7%), and 'Early HbA1c peak' (5%). Compared to the 'Stable but elevated HbA1c' group, the three other groups presented rapidly deteriorating glycaemic control during late childhood or adolescence, had higher HbA1c at study entry, and included fewer pump users, higher frequency of inadequate blood glucose monitoring, more severe hypoglycaemic events, lower proportions with Danish origin, and worse educational status of parents. The groups also represented significant differences by healthcare region. CONCLUSIONS: Children and adolescents with type 1 diabetes experience heterogenous trajectories with different timings and magnitudes of the deterioration of HbA1c levels, although the majority follow on average a stable, yet elevated HbA1c trajectory. The causes and long-term health implications of these heterogenous trajectories need to be addressed.

Towards precision medicine in diabetes? A critical review of glucotypes.

In response to a study previously published in PLOS Biology, this Formal Comment thoroughly examines the concept of 'glucotypes' with regard to its generalisability, interpretability and relationship to more traditional measures used to describe data from continuous glucose monitoring.

Loss of Sucrase-Isomaltase Function Increases Acetate Levels and Improves Metabolic Health in Greenlandic Cohorts.

BACKGROUND & AIMS: The sucrase-isomaltase (SI) c.273_274delAG loss-of-function variant is common in Arctic populations and causes congenital sucrase-isomaltase deficiency, which is an inability to break down and absorb sucrose and isomaltose. Children with this condition experience gastrointestinal symptoms when dietary sucrose is introduced. We aimed to describe the health of adults with sucrase-isomaltase deficiency. METHODS: The association between c.273_274delAG and phenotypes related to metabolic health was assessed in 2 cohorts of Greenlandic adults (n = 4922 and n = 1629). A sucrase-isomaltase knockout (Sis-KO) mouse model was used to further elucidate the findings. RESULTS: Homozygous carriers of the variant had a markedly healthier metabolic profile than the remaining population, including lower body mass index (ß [standard error], -2.0 [0.5] kg/m2; P = 3.1 × 10-5), body weight (-4.8 [1.4] kg; P = 5.1 × 10-4), fat percentage (-3.3% [1.0%]; P = 3.7 × 10-4), fasting triglyceride (-0.27 [0.07] mmol/L; P = 2.3 × 10-6), and remnant cholesterol (-0.11 [0.03] mmol/L; P = 4.2 × 10-5). Further analyses suggested that this was likely mediated partly by higher circulating levels of acetate observed in homozygous carriers (ß [standard error], 0.056 [0.002] mmol/L; P = 2.1 × 10-26), and partly by reduced sucrose uptake, but not lower caloric intake. These findings were verified in Sis-KO mice, which, compared with wild-type mice, were leaner on a sucrose-containing diet, despite similar caloric intake, had significantly higher plasma acetate levels in response to a sucrose gavage, and had lower plasma glucose level in response to a sucrose-tolerance test. CONCLUSIONS: These results suggest that sucrase-isomaltase constitutes a promising drug target for improvement of metabolic health, and that the health benefits are mediated by reduced dietary sucrose uptake and possibly also by higher levels of circulating acetate.

The effect of traditional diet on glucose homoeostasis in carriers and non-carriers of a common TBC1D4 variant in Greenlandic Inuit: a randomised crossover study.

Consumption of traditional foods is decreasing amid a lifestyle transition in Greenland as incidence of type 2 diabetes (T2D) increases. In homozygous carriers of a TBC1D4 variant, conferring postprandial insulin resistance, the risk of T2D is markedly higher. We investigated the effects of traditional marine diets on glucose homoeostasis and cardio-metabolic health in Greenlandic Inuit carriers and non-carriers of the variant in a randomised crossover study consisting of two 4-week dietary interventions: Traditional (marine-based, low-carbohydrate) and Western (high in imported meats and carbohydrates). Oral glucose tolerance test (OGTT, 2-h), 14-d continuous glucose and cardio-metabolic markers were assessed to investigate the effect of diet and genotype. Compared with the Western diet, the Traditional diet reduced mean and maximum daily blood glucose by 0·17 mmol/l (95 % CI 0·05, 0·29; P = 0·006) and 0·26 mmol/l (95 % CI 0·06, 0·46; P = 0·010), respectively, with dose-dependency. Furthermore, it gave rise to a weight loss of 0·5 kg (95 % CI; 0·09, 0·90; P = 0·016) relative to the Western diet and 4 % (95 % CI 1, 9; P = 0·018) lower LDL:HDL-cholesterol, which after adjustment for weight loss appeared to be driven by HDL elevation (0·09 mmol/l (0·03, 0·15), P = 0·006). A diet-gene interaction was indicated on insulin sensitivity in the OGTT (p = 0·093), which reflected a non-significant increase of 1·4 (-0·6, 3·5) mmol/l in carrier 2-h glucose. A Traditional diet marginally improved daily glycaemic control and plasma lipid profile compared with a Westernised diet in Greenlandic Inuit. Possible adverse effects on glucose tolerance in carriers of the TBC1D4 variant warrant further studies.

The derived allele of a novel intergenic variant at chromosome 11 associates with lower body mass index and a favorable metabolic phenotype in Greenlanders.

The genetic architecture of the small and isolated Greenlandic population is advantageous for identification of novel genetic variants associated with cardio-metabolic traits. We aimed to identify genetic loci associated with body mass index (BMI), to expand the knowledge of the genetic and biological mechanisms underlying obesity. Stage 1 BMI-association analyses were performed in 4,626 Greenlanders. Stage 2 replication and meta-analysis were performed in additional cohorts comprising 1,058 Yup'ik Alaska Native people, and 1,529 Greenlanders. Obesity-related traits were assessed in the stage 1 study population. We identified a common variant on chromosome 11, rs4936356, where the derived G-allele had a frequency of 24% in the stage 1 study population. The derived allele was genome-wide significantly associated with lower BMI (beta (SE), -0.14 SD (0.03), p = 3.2x10-8), corresponding to 0.64 kg/m2 lower BMI per G allele in the stage 1 study population. We observed a similar effect in the Yup'ik cohort (-0.09 SD, p = 0.038), and a non-significant effect in the same direction in the independent Greenlandic stage 2 cohort (-0.03 SD, p = 0.514). The association remained genome-wide significant in meta-analysis of the Arctic cohorts (-0.10 SD (0.02), p = 4.7x10-8). Moreover, the variant was associated with a leaner body type (weight, -1.68 (0.37) kg; waist circumference, -1.52 (0.33) cm; hip circumference, -0.85 (0.24) cm; lean mass, -0.84 (0.19) kg; fat mass and percent, -1.66 (0.33) kg and -1.39 (0.27) %; visceral adipose tissue, -0.30 (0.07) cm; subcutaneous adipose tissue, -0.16 (0.05) cm, all p<0.0002), lower insulin resistance (HOMA-IR, -0.12 (0.04), p = 0.00021), and favorable lipid levels (triglyceride, -0.05 (0.02) mmol/l, p = 0.025; HDL-cholesterol, 0.04 (0.01) mmol/l, p = 0.0015). In conclusion, we identified a novel variant, where the derived G-allele possibly associated with lower BMI in Arctic populations, and as a consequence also leaner body type, lower insulin resistance, and a favorable lipid profile.

Childhood body mass index trajectories and associations with adult-onset chronic kidney disease in Denmark: A population-based cohort study.

BACKGROUND: Although excess adult adiposity is a strong risk factor for chronic kidney disease (CKD), evidence for associations with early life body size is limited. We investigated whether childhood body mass index (BMI) trajectories are associated with adult-onset CKD and end-stage kidney disease (ESKD) using a population-based cohort. Further, we examined the role of adult-onset type 2 diabetes (T2D) in these associations. METHODS AND FINDINGS: We included 151,506 boys and 148,590 girls from the Copenhagen School Health Records Register, born 1930 to 1987 with information on measured weights and heights at ages 6 to 15 years. Five sex-specific childhood BMI trajectories were analyzed. Information on the main outcomes CKD and ESKD, as well as T2D, came from national health registers. Incidence rate ratios (IRRs) and 95% confidence intervals (CIs) were estimated using Poisson regression adjusted for year of birth. During a median of 30.8 person-years of follow-up, 5,968 men and 3,903 women developed CKD and 977 men and 543 women developed ESKD. For both sexes, the rates of CKD and ESKD increased significantly with higher child BMI trajectories in comparison with the average BMI trajectory (40% to 43% of individuals) and the below-average BMI trajectory (21% to 23% of individuals) had the lowest rates. When including T2D, most associations were significant and men (IRR = 1.39, 95% CI: 1.13 to 1.72) and women (IRR = 1.54, 95% CI: 1.28 to 1.86) with the obese childhood BMI trajectory (2% of individuals) had significantly higher CKD rates than the average BMI trajectory, whereas for ESKD, the associations were positive, but nonsignificant, for men (IRR = 1.38, 95% CI: 0.83 to 2.31) but significant for women (IRR = 1.97, 95% CI: 1.25 to 3.11) with the obese BMI trajectory. A main study limitation is the use of only hospital-based CKD diagnoses. CONCLUSIONS: Individuals with childhood BMI trajectories above average had higher rates of CKD and ESKD than those with an average childhood BMI trajectory. When including T2D, most associations were significant, particularly with CKD, emphasizing the potential information that the early appearance of above-average BMI growth patterns provide in relation to adult-onset CKD beyond the information provided by T2D development.

Trajectory and predictors of HbA1c in children and adolescents with type 1 diabetes-A Danish nationwide cohort study.

OBJECTIVES: Poor glycemic control in type 1 diabetes increases the risk of chronic complications and it is essential to identify life periods and predictors associated with deteriorating HbA1c . The aim was to describe specific HbA1c trajectories in Danish children and adolescents with type 1 diabetes and study associations with clinical and sociodemographic factors. RESEARCH DESIGN AND METHODS: 5889 children with type 1 diabetes were included from the nationwide Danish Registry of Childhood and Adolescent Diabetes with annual visits during 1996-2019. Trajectories of HbA1c were modeled with linear mixed-effects models (using age as time scale, included as cubic spline) and with an individual-specific random intercept and slope. The following cofactors were included stepwise into the model: sex, age at diagnosis, calendar year, parental education, immigrant status, health care region, blood glucose monitoring (BGM) frequency, treatment modalities: continuous subcutaneous insulin infusion (pump) versus multiple daily insulin injection therapy (pen) and continuous glucose monitoring. RESULTS: HbA1c overall increased during age while there was a significant decreasing secular trend. Older age at diagnosis was associated with a steeper trajectory, and non-Danish origin and shorter parental education were each associated with higher levels of HbA1c across age. A lower BGM frequency was associated with a markedly poorer HbA1c trajectory, while no significant differences were shown for different treatment modalities. CONCLUSIONS: Glycemic outcome worsened with age during childhood and adolescence, which is of clinical concern. Important predictors for a poorer glycemic trajectory were later age at diabetes diagnosis, shorter parental education, non-Danish origin and, in particular low BGM frequency.

The effects of dapagliflozin, metformin or exercise on glycaemic variability in overweight or obese individuals with prediabetes (the PRE-D Trial): a multi-arm, randomised, controlled trial.

AIMS/HYPOTHESIS: We aimed to investigate the short-term efficacy and safety of three glucose-lowering interventions in overweight or obese individuals with prediabetes defined by HbA1c. METHODS: The PRE-D Trial was a randomised, controlled, parallel, multi-arm, open-label, non-blinded trial performed at Steno Diabetes Center Copenhagen, Gentofte, Denmark. One hundred and twenty participants with BMI ≥25 kg/m2, 30-70 years of age, and prediabetes (HbA1c 39-47 mmol/mol [5.7-6.4%]) were randomised 1:1:1:1 to dapagliflozin (10 mg once daily), metformin (1700 mg daily), interval-based exercise (5 days/week, 30 min/session) or control (habitual lifestyle). Participants were examined at baseline and at 6, 13 and 26 weeks after randomisation. The primary outcome was the 13 week change in glycaemic variability (calculated as mean amplitude of glycaemic excursions [MAGE]) determined using a continuous glucose monitoring system (pre-specified minimal clinically important difference in MAGE ∼30%). RESULTS: One hundred and twelve participants attended the examination at 13 weeks and 111 attended the follow-up visit at 26 weeks. Compared with the control group, there was a small decrease in MAGE in the dapagliflozin group (17.1% [95% CI 0.7, 30.8], p = 0.042) and a small, non-significant, reduction in the exercise group (15.3% [95% CI -1.2, 29.1], p = 0.067), whereas MAGE was unchanged in the metformin group (0.1% [95% CI -16.1, 19.4], p = 0.991)). Compared with the metformin group, MAGE was 17.2% (95% CI 0.8, 30.9; p = 0.041) lower in the dapagliflozin group and 15.4% (95% CI -1.1, 29.1; p = 0.065) lower in the exercise group after 13 weeks, with no difference between exercise and dapagliflozin (2.2% [95% CI -14.8, 22.5], p = 0.815). One serious adverse event occurred in the control group (lung cancer). CONCLUSIONS/INTERPRETATION: Treatment with dapagliflozin and interval-based exercise lead to similar but small improvements in glycaemic variability compared with control and metformin therapy. The clinical importance of these findings in prediabetes is uncertain. TRIAL REGISTRATION: ClinicalTrials.gov NCT02695810 FUNDING: The study was funded by the Novo Nordisk Foundation, AstraZeneca AB, the Danish Innovation Foundation, the University of Copenhagen and Ascensia Diabetes Care Denmark ApS Graphical abstract.

Physical activity attenuates postprandial hyperglycaemia in homozygous TBC1D4 loss-of-function mutation carriers.

AIMS/HYPOTHESIS: The common muscle-specific TBC1D4 p.Arg684Ter loss-of-function variant defines a subtype of non-autoimmune diabetes in Arctic populations. Homozygous carriers are characterised by elevated postprandial glucose and insulin levels. Because 3.8% of the Greenlandic population are homozygous carriers, it is important to explore possibilities for precision medicine. We aimed to investigate whether physical activity attenuates the effect of this variant on 2 h plasma glucose levels after an oral glucose load. METHODS: In a Greenlandic population cohort (n = 2655), 2 h plasma glucose levels were obtained after an OGTT, physical activity was estimated as physical activity energy expenditure and TBC1D4 genotype was determined. We performed TBC1D4-physical activity interaction analysis, applying a linear mixed model to correct for genetic admixture and relatedness. RESULTS: Physical activity was inversely associated with 2 h plasma glucose levels (ß[main effect of physical activity] -0.0033 [mmol/l] / [kJ kg-1 day-1], p = 6.5 × 10-5), and significantly more so among homozygous carriers of the TBC1D4 risk variant compared with heterozygous carriers and non-carriers (ß[interaction] -0.015 [mmol/l] / [kJ kg-1 day-1], p = 0.0085). The estimated effect size suggests that 1 h of vigorous physical activity per day (compared with resting) reduces 2 h plasma glucose levels by an additional ~0.7 mmol/l in homozygous carriers of the risk variant. CONCLUSIONS/INTERPRETATION: Physical activity improves glucose homeostasis particularly in homozygous TBC1D4 risk variant carriers via a skeletal muscle TBC1 domain family member 4-independent pathway. This provides a rationale to implement physical activity as lifestyle precision medicine in Arctic populations. DATA REPOSITORY: The Greenlandic Cardio-Metabochip data for the Inuit Health in Transition study has been deposited at the European Genome-phenome Archive ( https://www.ebi.ac.uk/ega/dacs/EGAC00001000736 ) under accession EGAD00010001428.

Cardiovascular outcomes with sodium-glucose cotransporter-2 inhibitors vs other glucose-lowering drugs in 13 countries across three continents: analysis of CVD-REAL data.

BACKGROUND: Randomized, controlled cardiovascular outcome trials may not be fully representative of the management of patients with type 2 diabetes across different geographic regions. We conducted analyses of data from the multinational CVD-REAL consortium to determine the association between initiation of sodium-glucose cotransporter-2 inhibitors (SGLT-2i) and cardiovascular outcomes, including subgroup analyses based on patient characteristics. METHODS: De-identified health records from 13 countries across three continents were used to identify patients newly-initiated on SGLT-2i or other glucose-lowering drugs (oGLDs). Propensity scores for SGLT-2i initiation were developed in each country, with 1:1 matching for oGLD initiation. In the matched groups hazard ratios (HRs) for hospitalization for heart failure (HHF), all-cause death (ACD), the composite of HHF or ACD, myocardial infarction (MI) and stroke were estimated by country, and pooled using a weighted meta-analysis. Multiple subgroup analyses were conducted across patient demographic and clinical characteristics to examine any heterogeneity in treatment effects. RESULTS: Following matching, 440,599 new users of SGLT-2i and oGLDs were included in each group. Mean follow-up time was 396 days for SGLT-2i initiation and 406 days for oGLDs initiation. SGLT-2i initiation was associated with a lower risk of HHF (HR: 0.66, 95%CI 0.58-0.75; p < 0.001), ACD (HR: 0.52, 95%CI 0.45-0.60; p < 0.001), the composite of HHF or ACD (HR: 0.60, 95%CI 0.53-0.68; p < 0.001), MI (HR: 0.85, 95%CI 0.78-0.92; p < 0.001), and stroke (HR: 0.78, 95%CI 0.72-0.85; p < 0.001); regardless of patient characteristics, including established cardiovascular disease, or geographic region. CONCLUSIONS: This CVD-REAL study extends the findings from the SGLT-2i clinical trials to the broader setting of an ethnically and geographically diverse population, and across multiple subgroups. Trial registration NCT02993614.

A large remaining potential in lipid-lowering drug treatment in the type 2 diabetes population: A Danish nationwide cohort study.

AIM: To assess lipid-lowering drug (LLD) use patterns during 1996-2017 and examine lipid levels in relation to the use of LLDs and prevalent atherosclerotic cardiovascular disease (ASCVD). METHODS: Using a nationwide diabetes register, 404 389 individuals with type 2 diabetes living in Denmark during 1996-2017 were identified. Individuals were followed from 1 January 1996 or date of type 2 diabetes diagnosis until date of emigration, death or 1 January 2017. Redemptions of prescribed LLDs were ascertained from the nationwide Register of Medicinal Products Statistics. Data on lipid levels were sourced from the National Laboratory Database since 2010. LLD coverage was calculated at any given time based on the redeemed amount and dose. Trends in lipid levels were estimated using an additive mixed-effect model. Low-density lipoprotein cholesterol (LDL-C) goal attainment was assessed based on recommended targets by the 2011, 2016 and 2019 guidelines for management of dyslipidaemias. RESULTS: LLD use has decreased since 2012 and only 55% of those with type 2 diabetes were LLD users in 2017. A decline in levels of total cholesterol and LDL-C, and an increase in triglycerides, was observed during 2010-2017. Annual mean levels of LDL-C were lower among LLD users compared with non-users (in 2017: 1.84 vs. 2.57 mmol/L). A greater fraction of LLD users achieved the LDL-C goal of less than 1.8 mmol/L compared with non-users (in 2017: 51.7% and 19%, respectively). Among LLD users with prevalent ASCVD, 26.9% and 55% had, as recommended by current 2019 European guidelines, an LDL-C level of less than 1.4 mmol/L and less than 1.8 mmol/L, respectively, in 2017. CONCLUSIONS: LLD use and LDL-C levels are far from optimal in the Danish type 2 diabetes population and improvement in LLD use could reduce ASCVD events.

No effects of dapagliflozin, metformin or exercise on plasma glucagon concentrations in individuals with prediabetes: A post hoc analysis from the randomized controlled PRE-D trial.

AIM: To assess the effects of dapagliflozin, metformin and exercise treatment on changes in plasma glucagon concentrations in individuals with overweight and HbA1c-defined prediabetes. MATERIALS AND METHODS: One-hundred and twenty individuals with overweight (body mass index ≥ 25 kg/m2 ) and prediabetes (HbA1c of 39-47 mmol/mol) were randomized to a 13-week intervention with dapagliflozin (10 mg once daily), metformin (850 mg twice daily), exercise (30 minutes of interval training 5 days per week) or control (habitual living). A 75-g oral glucose tolerance test (OGTT) (0, 30, 60 and 120 minutes) was administered at baseline, at 13 weeks (end of intervention) and at 26 weeks (end of follow-up). Linear mixed effects models with participant-specific random intercepts were used to investigate associations of the interventions with fasting plasma glucagon concentration, insulin/glucagon ratio and glucagon suppression during the OGTT. RESULTS: At baseline, the median (Q1; Q3) age was 62 (54; 68) years, median fasting plasma glucagon concentration was 11 (7; 15) pmol/L, mean (SD) HbA1c was 40.9 (2.3) mmol/mol and 56% were women. Compared with the control group, fasting glucagon did not change in any of the groups from baseline to the end of the intervention (dapagliflozin group: -5% [95% CI: -29; 26]; exercise group: -8% [95% CI: -31; 24]; metformin group: -2% [95% CI: -27; 30]). Likewise, there were no differences in insulin/glucagon ratio and glucagon suppression during the OGTT between the groups. CONCLUSIONS: In individuals with prediabetes, 13 weeks of treatment with dapagliflozin, metformin or exercise was not associated with changes in fasting or post-OGTT glucagon concentrations.

Metformin may adversely affect orthostatic blood pressure recovery in patients with type 2 diabetes: substudy from the placebo-controlled Copenhagen Insulin and Metformin Therapy (CIMT) trial.

BACKGROUND: Metformin has been shown to have both neuroprotective and neurodegenerative effects. The aim of this study was to investigate the effect of metformin in combination with insulin on cardiovascular autonomic neuropathy (CAN) and distal peripheral neuropathy (DPN) in individuals with type 2 diabetes (T2DM). METHODS: The study is a sub-study of the CIMT trial, a randomized placebo-controlled trial with a 2 × 3 factorial design, where 412 patients with T2DM were randomized to 18 months of metformin or placebo in addition to open-labelled insulin. Outcomes were measures of CAN: Changes in heart rate response to deep breathing (beat-to-beat), orthostatic blood pressure (OBP) and heart rate and vibration detection threshold (VDT) as a marker DPN. Serum levels of vitamin B12 and methyl malonic acid (MMA) were analysed. RESULTS: After 18 months early drop in OBP (30 s after standing) was increased in the metformin group compared to placebo: systolic blood pressure drop increased by 3.4 mmHg (95% CI 0.6; 6.2, p = 0.02) and diastolic blood pressure drop increased by 1.3 mmHg (95% CI 0.3; 2.6, p = 0.045) compared to placebo. Beat-to-beat variation decreased in the metformin group by 1.1 beats per minute (95% CI - 2.4; 0.2, p = 0.10). Metformin treatment did not affect VDT group difference - 0.33 V (95% CI - 1.99; 1.33, p = 0.39) or other outcomes. Changes in B12, MMA and HbA1c did not confound the associations. CONCLUSIONS: Eighteen months of metformin treatment in combination with insulin compared with insulin alone increased early drop in OBP indicating an adverse effect of metformin on CAN independent of vitamin B12, MMA HbA1c. Trial registration The protocol was approved by the Regional Committee on Biomedical Research Ethics (H-D-2007-112), the Danish Medicines Agency and registered with ClinicalTrials.gov (NCT00657943).

A common Greenlandic TBC1D4 variant confers muscle insulin resistance and type 2 diabetes.

The Greenlandic population, a small and historically isolated founder population comprising about 57,000 inhabitants, has experienced a dramatic increase in type 2 diabetes (T2D) prevalence during the past 25 years. Motivated by this, we performed association mapping of T2D-related quantitative traits in up to 2,575 Greenlandic individuals without known diabetes. Using array-based genotyping and exome sequencing, we discovered a nonsense p.Arg684Ter variant (in which arginine is replaced by a termination codon) in the gene TBC1D4 with an allele frequency of 17%. Here we show that homozygous carriers of this variant have markedly higher concentrations of plasma glucose (ß = 3.8 mmol l(-1), P = 2.5 × 10(-35)) and serum insulin (ß = 165 pmol l(-1), P = 1.5 × 10(-20)) 2 hours after an oral glucose load compared with individuals with other genotypes (both non-carriers and heterozygous carriers). Furthermore, homozygous carriers have marginally lower concentrations of fasting plasma glucose (ß = -0.18 mmol l(-1), P = 1.1 × 10(-6)) and fasting serum insulin (ß = -8.3 pmol l(-1), P = 0.0014), and their T2D risk is markedly increased (odds ratio (OR) = 10.3, P = 1.6 × 10(-24)). Heterozygous carriers have a moderately higher plasma glucose concentration 2 hours after an oral glucose load than non-carriers (ß = 0.43 mmol l(-1), P = 5.3 × 10(-5)). Analyses of skeletal muscle biopsies showed lower messenger RNA and protein levels of the long isoform of TBC1D4, and lower muscle protein levels of the glucose transporter GLUT4, with increasing number of p.Arg684Ter alleles. These findings are concomitant with a severely decreased insulin-stimulated glucose uptake in muscle, leading to postprandial hyperglycaemia, impaired glucose tolerance and T2D. The observed effect sizes are several times larger than any previous findings in large-scale genome-wide association studies of these traits and constitute further proof of the value of conducting genetic association studies outside the traditional setting of large homogeneous populations.

Effect of duration and burden of microvascular complications on mortality rate in type 1 diabetes: an observational clinical cohort study.

AIMS/HYPOTHESIS: The role of burden and duration of multiple microvascular complications on mortality rate has not been explored in detail in type 1 diabetes. Taking complication burden and time-updated duration into account we aimed to quantify mortality rate in individuals with and without microvascular complications. METHODS: This observational clinical cohort included 3828 individuals with type 1 diabetes attending the Steno Diabetes Center Copenhagen in 2001-2013. We used information on mortality and detailed clinical measures of microvascular complications from electronic patient records. Poisson models were used to model mortality rates according to complication burden. RESULTS: During 26,665 person-years of follow-up, 503 deaths occurred. Compared with individuals without microvascular complications, the mortality rate ratio was 2.20 (95% CI 1.79, 2.69) for individuals with diabetic kidney disease, 1.72 (95% CI 1.39, 2.12) for individuals with neuropathy and 1.02 (95% CI 0.77, 1.37) for individuals with retinopathy, all adjusted for calendar time (year/month/day), age, duration of diabetes, sex, HbA1c, LDL-cholesterol, BMI, smoking status, systolic blood pressure, use of antihypertensive and lipid-lowering medication, and cardiovascular disease status. In individuals with two complications or more, the risk of mortality did not exceed the combined risk from each individual complication. Mortality rate ratios increased immediately after diagnosis of neuropathy and diabetic kidney disease. Mortality rate ratios were independent of the duration of neuropathy and retinopathy, while the mortality rate associated with diabetic kidney disease reached a stable level after approximately 3 years. CONCLUSIONS/INTERPRETATION: Neuropathy and diabetic kidney disease are strong and independent risk markers of mortality in type 1 diabetes, whereas no evidence of higher mortality rate was found for retinopathy. We found no indication that the mortality risk with multiple complications exceeds the risk conferred by each complication separately. The duration spent with microvascular complications had only a marginal effect on mortality.

Reversion from prediabetes to normoglycaemia and risk of cardiovascular disease and mortality: the Whitehall II cohort study.

AIMS/HYPOTHESIS: Reversion from prediabetes to normoglycaemia is accompanied by an improvement in cardiovascular risk factors, but it is unclear whether this translates into a reduction in risk of cardiovascular disease (CVD) events or death. Hence, we studied the probability of reversion from prediabetes to normoglycaemia and the associated risk of future CVD and death using data from the Whitehall II observational cohort study. METHODS: Three glycaemic criteria for prediabetes (fasting plasma glucose [FPG] 5.6-6.9 mmol/l, 2 h plasma glucose [2hPG] 7.8-11.0 mmol/l, and HbA1c 39-47 mmol/mol [5.7-6.4%]) were assessed in 2002-2004 and 2007-2009 for 5193 participants free of known diabetes at enrolment. Among participants with prediabetes in the first examination, we calculated the probability of reversion to normoglycaemia by re-examination according to each glycaemic criterion. Poisson regression analysis was used to estimate and compare incidence rates of a composite endpoint of a CVD event or death in participants with prediabetes who did vs did not revert to normoglycaemia. Analyses were adjusted for age, sex, ethnicity and previous CVD. RESULTS: Based on the FPG criterion, 820 participants had prediabetes and 365 (45%) of them had reverted to normoglycaemia in 5 years. The corresponding numbers were 324 and 120 (37%) for the 2hPG criterion and 1709 and 297 (17%) for the HbA1c criterion. During a median follow-up of 6.7 (interquartile range 6.3-7.2) years, 668 events of non-fatal CVD or death occurred among the 5193 participants. Reverting from 2hPG-defined prediabetes to normoglycaemia vs remaining prediabetic or progressing to diabetes was associated with a halving in event rate (12.7 vs 29.1 per 1000 person-years, p = 0.020). No association with event rate was observed for reverting from FPG-defined (18.6 vs 18.2 per 1000 person-years, p = 0.910) or HbA1c-defined prediabetes to normoglycaemia (24.5 vs 22.9 per 1000 person-years, p = 0.962). CONCLUSIONS/INTERPRETATION: Most people with HbA1c-defined prediabetes remained prediabetic or progressed to diabetes during 5 years of follow-up. In contrast, reversion to normoglycaemia was frequent among people with FPG- or 2hPG-defined prediabetes. Only reversion from 2hPG-defined prediabetes to normoglycaemia was associated with a reduction in future risk of CVD and death.

A novel rare CUBN variant and three additional genes identified in Europeans with and without diabetes: results from an exome-wide association study of albuminuria.

AIMS/HYPOTHESIS: Identifying rare coding variants associated with albuminuria may open new avenues for preventing chronic kidney disease and end-stage renal disease, which are highly prevalent in individuals with diabetes. Efforts to identify genetic susceptibility variants for albuminuria have so far been limited, with the majority of studies focusing on common variants. METHODS: We performed an exome-wide association study to identify coding variants in a two-stage (discovery and replication) approach. Data from 33,985 individuals of European ancestry (15,872 with and 18,113 without diabetes) and 2605 Greenlanders were included. RESULTS: We identified a rare (minor allele frequency [MAF]: 0.8%) missense (A1690V) variant in CUBN (rs141640975, ß = 0.27, p = 1.3 × 10-11) associated with albuminuria as a continuous measure in the combined European meta-analysis. The presence of each rare allele of the variant was associated with a 6.4% increase in albuminuria. The rare CUBN variant had an effect that was three times stronger in individuals with type 2 diabetes compared with those without (pinteraction = 7.0 × 10-4, ß with diabetes = 0.69, ß without diabetes = 0.20) in the discovery meta-analysis. Gene-aggregate tests based on rare and common variants identified three additional genes associated with albuminuria (HES1, CDC73 and GRM5) after multiple testing correction (pBonferroni < 2.7 × 10-6). CONCLUSIONS/INTERPRETATION: The current study identifies a rare coding variant in the CUBN locus and other potential genes associated with albuminuria in individuals with and without diabetes. These genes have been implicated in renal and cardiovascular dysfunction. The findings provide new insights into the genetic architecture of albuminuria and highlight target genes and pathways for the prevention of diabetes-related kidney disease.

Associations of fat mass and fat-free mass accretion in infancy with body composition and cardiometabolic risk markers at 5 years: The Ethiopian iABC birth cohort study.

BACKGROUND: Accelerated growth in early childhood is an established risk factor for later obesity and cardiometabolic disease, but the relative importance of fat mass (FM) and fat-free mass (FFM) accretion is not well understood. We aimed to study how FM and FFM at birth and their accretion during infancy were associated with body composition and cardiometabolic risk markers at 5 years. METHODS AND FINDINGS: Healthy children born at term were enrolled in the Infant Anthropometry and Body Composition (iABC) birth cohort between December 2008 and October 2012 at Jimma University Specialized Hospital in the city of Jimma, Ethiopia. FM and FFM were assessed using air displacement plethysmography a median of 6 times between birth and 6 months of age. In 507 children, we estimated individual FM and FFM at birth and their accretion over 0-3 and 3-6 months of age using linear-spline mixed-effects modelling. We analysed associations of FM and FFM at birth and their accretion in infancy with height, waist circumference, FM, FFM, and cardiometabolic risk markers at 5 years using multiple linear regression analysis. A total of 340 children were studied at the 5-year follow-up (mean age: 60.0 months; girls: 50.3%; mean wealth index: 45.5 out of 100; breastfeeding status at 4.5 to 6 months post-partum: 12.5% exclusive, 21.4% almost exclusive, 60.6% predominant, 5.5% partial/none). Higher FM accretion in infancy was associated with higher FM and waist circumference at 5 years. For instance, 100-g/month higher FM accretion in the periods 0-3 and 3-6 months was associated with 339 g (95% CI: 243-435 g, p < 0.001) and 367 g (95% CI: 250-484 g, p < 0.001) greater FM at 5 years, respectively. Higher FM at birth and FM accretion from 0 to 3 months were associated with higher FFM and cholesterol concentrations at 5 years. Associations for cholesterol were strongest for low-density lipoprotein (LDL)-cholesterol, and remained significant after adjusting for current FM. A 100-g higher FM at birth and 100-g/month higher FM accretion from 0 to 3 months were associated with 0.16 mmol/l (95% CI: 0.05-0.26 mmol/l, p = 0.005) and 0.06 mmol/l (95% CI: 0.01-0.12 mmol/l, p = 0.016) higher LDL-cholesterol at 5 years, respectively. Higher FFM at birth and FFM accretion in infancy were associated with higher FM, FFM, waist circumference, and height at 5 years. For instance, 100-g/month higher FFM accretion in the periods 0-3 and 3-6 months was associated with 1,002 g (95% CI: 815-1,189 g, p < 0.001) and 624 g (95% CI: 419-829 g, p < 0.001) greater FFM at 5 years, respectively. We found no associations of FM and FFM growth with any of the other studied cardiometabolic markers including glucose, HbA1c, insulin, C-peptide, HOMA-IR, triglycerides, and blood pressure. Non-attendance at the 5-year follow-up visit was the main limitation of this study, which may have introduced selection bias and limited the power of the regression analyses. CONCLUSIONS: FM accretion in early life was positively associated with markers of adiposity and lipid metabolism, but not with blood pressure and cardiometabolic markers related to glucose homeostasis. FFM accretion was primarily related to linear growth and FFM at 5 years.

Greater glucagon-like peptide-1 responses to oral glucose are associated with lower central and peripheral blood pressures.

BACKGROUND AND AIM: Cardiovascular diseases (CVDs) are globally the leading cause of death and hypertension is a significant risk factor. Treatment with glucagon-like peptide-1 (GLP-1) receptor agonists has been associated with decreases in blood pressure and CVD risk. Our aim was to investigate the association between endogenous GLP-1 responses to oral glucose and peripheral and central haemodynamic measures in a population at risk of diabetes and CVD. METHODS: This cross-sectional study included 837 Danish individuals from the ADDITION-PRO cohort (52% men, median (interquartile range) age 65.5 (59.8 to 70.7) years, BMI 26.1 (23.4 to 28.5) kg/m2, without antihypertensive treatment and known diabetes). All participants received an oral glucose tolerance test with measurements of GLP-1 at 0, 30 and 120 min. Aortic stiffness was assessed by pulse wave velocity (PWV). The associations between GLP-1 response and central and brachial blood pressure (BP) and PWV were assessed in linear regression models adjusting for age and sex. RESULTS: A greater GLP-1 response was associated with lower central systolic and diastolic BP of - 1.17 mmHg (95% confidence interval (CI) - 2.07 to - 0.27 mmHg, P = 0.011) and - 0.74 mmHg (95% CI - 1.29 to - 0.18 mmHg, P = 0.009), respectively, as well as lower brachial systolic and diastolic BP of - 1.27 mmHg (95% CI - 2.20 to - 0.33 mmHg, P = 0.008) and - 1.00 (95% CI - 1.56 to - 0.44 mmHg, P = 0.001), respectively. PWV was not associated with GLP-1 release (P = 0.3). Individuals with the greatest quartile of GLP-1 response had clinically relevant lower BP measures compared to individuals with the lowest quartile of GLP-1 response (central systolic BP: - 4.94 (95% CI - 8.56 to - 1.31) mmHg, central diastolic BP: - 3.05 (95% CI - 5.29 to - 0.80) mmHg, brachial systolic BP: - 5.18 (95% CI - 8.94 to - 1.42) mmHg, and brachial diastolic BP: - 2.96 (95% CI - 5.26 to - 0.67) mmHg). CONCLUSION: Greater glucose-stimulated GLP-1 responses were associated with clinically relevant lower central and peripheral blood pressures, consistent with beneficial effects on the cardiovascular system and reduced risk of CVD and mortality. Trial registration ClinicalTrials.gov Identifier: NCT00237549. Retrospectively registered 10 October 2005.