Type 1 diabetes is a complex autoimmune disorder in which autoreactive CD4⁺ and CD8⁺ T cells destroy pancreatic beta-cells, resulting in insulin deficiency and hyperglycemia. Although genetic susceptibility, particularly certain HLA alleles, contributes to disease risk, not all genetically predisposed individuals develop Type 1 diabetes. Screening first degree relatives (FDRs) for islet autoantibodies (GAD65, IAA, IA-2, ZnT8) helps detect autoimmune activity. However, these serum markers arise only after T-helper cell activation, limiting early intervention opportunities. Since protein antigen recognition by B cells requires T-helper cell assistance through linked recognition, T cell activation precedes B cell activation and autoantibody production. Activation of these T cells leads to shedding of the immune-regulatory (activation) surface protein LAG-3 (Lymphocyte Activation Gene-3 or CD223), generating its soluble form, sLAG-3, that is detectable in circulation. We hypothesized that sLAG-3 may serve as an early biomarker of autoimmune activity preceding islet autoantibody development in type 1 diabetes. Plasma sLAG-3 levels were measured longitudinally in female diabetes-prone NOD mice and analyzed in relation to islet antigen-specific CD4⁺ T cell expansion and diabetes onset. To mechanistically link autoreactive T cell activation to sLAG-3 release. Naive autoreactive C6.6.9 TCR-transgenic (TCR-Tg) CD4⁺ T cells were adoptively transferred into NOD.SCID mice and longitudinal assessment for plasma sLAG-3, beta-cell antigen specific CD4⁺ T cell tetramer profiles, and circulating insulin ( Ins2 ) mRNA to determine ongoing beta-cell stress. In parallel, sLAG-3 levels were analyzed from different human cohorts, including FDRs of individuals with type 1 diabetes, using cross-sectional and longitudinal approaches. In murine models, elevated sLAG-3 correlated with expansion of islet-specific CD4⁺ T cells that preceded hyperglycemia and diabetes onset. In the adoptive transfer model, early increases in sLAG-3 and circulating Ins2 mRNA marked immune activation and emerging beta-cell stress prior to overt diabetes. In our human cohorts, sLAG-3 was detectable in autoantibody-negative and single-autoantibody-positive FDRs, with higher levels observed in progressors compared to non-progressors, and associated with high-risk HLA genotypes. These findings identify sLAG-3 as a candidate biomarker of early T cell activation in type 1 diabetes that may precede islet autoantibody development. Integration of sLAG-3 with antigen-specific T cell and beta-cell stress markers could improve early risk stratification and inform preventive strategies before substantial loss of beta-cell. Prospective longitudinal studies aligned to seroconversion are required to validate sLAG-3 as a surrogate marker of early disease activity. What is already known about this subject?: Before the clinical onset of hyperglycemia, type 1 diabetes is characterized by a prolonged preclinical phase in which autoreactive B and T cells mediate progressive beta-cell destruction.Current risk stratification strategies rely mainly on genetic susceptibility (genomic DNA) and the detection of islet autoantibodies in plasma/serum.Islet autoantibodies arise only after CD4⁺ T cell activation and therefore do not capture the earliest stages of immune dysregulation.Consequently, biomarkers that directly reflect early pathogenic T cell activity prior to, or independent of, seroconversion remain limited and insufficiently validated.What is the key question?: Can plasma sLAG-3 levels, beta-cell antigen-specific CD4⁺ T cell tetramer expression, and circulating Ins2 mRNA serve as very early biomarkers of autoimmune activity in type 1 diabetes and serve to better inform risk stratification, thereby informing preventive intervention strategies for the clinician? What are the new findings?: sLAG-3 increases transiently during early antigen-specific CD4⁺ T cell activation stage, precedes hyperglycemia in mouse models, and is elevated in autoantibody-negative and single-autoantibody-positive first-degree relatives who later progress to type 1 diabetes. sLAG-3 was associated with beta-cell antigen-specific CD4⁺ T cell expansion, assessment of stress induced beta cell Ins2 mRNA release and high-risk HLA genotypes, indicating early autoimmune activation rather than established disease. How might this impact clinical practice in the foreseeable future?: These findings support sLAG-3 as a candidate early biomarker of T cell activation, before or at the earliest stages of islet autoantibody development in some at-risk individuals. Integration of plasma sLAG-3 with beta-cell antigen specific CD4⁺ T cell profiling and insulin mRNA measurements could complement current autoantibody-based screening, improve risk stratification, and enable earlier preventive interventions to preserve beta-cell function in patients at-risk for type 1 diabetes.

The role of red meat in type 1 diabetes risk remains unclear. We examined whether maternal and early-life red meat intake is associated with the development of type 1 diabetes and whether such associations are modified by genetic susceptibility. We analysed data from 15,717 children participating in the All Babies In Southeast Sweden (ABIS) cohort, followed for type 1 diabetes diagnosis via national registers until the age of 24-26 years. Dietary intake was assessed through food frequency questionnaires during pregnancy and at ages 1, 2.5 and 5 years. Cox models estimated adjusted HRs and 95% CIs for type 1 diabetes in relation to red meat, including beef, pork and sausage, analysed as high vs low intake frequency and per serving/week. Analyses were stratified by HLA risk genotype and family history of type 1 diabetes. Frequency of red meat intake during pregnancy or at age 1 was not associated with type 1 diabetes risk. The corresponding HRs per serving/week were 0.98 (95% CI 0.90, 1.07) and 0.98 (95% CI 0.88, 1.08), respectively. In type-specific analyses, higher frequency of beef intake at age 5 was associated with an increased risk of type 1 diabetes (HR 1.29 [95% CI 1.05, 1.58]), with a similar tendency for exposure at age 2.5 (HR 1.12 [95% CI 0.93, 1.36]). The association at age 5 was evident among children with high-risk HLA genotypes (HR 1.40 [95% CI 1.11, 1.78]) or a family history of type 1 diabetes (HR 1.56 [95% CI 1.08, 2.26]). In contrast, no statistically significant association was observed among children with low-risk HLA genotypes (HR 0.34 [95% CI 0.10, 1.19]) or without a family history of type 1 diabetes (HR 1.20 [95% CI 0.92, 1.56]). No associations were found for higher frequency of beef consumption during pregnancy or at age 1, nor for pork and sausage at any age. Childhood beef consumption may contribute to type 1 diabetes development in genetically at-risk individuals. Further research is needed to confirm this finding and clarify underlying mechanisms.

The destruction of pancreatic beta cells in type 1 diabetes (T1D) begins years before clinical symptoms appear, yet most patients are diagnosed only after losing 80% to 90% of their insulin-producing capacity. Identifying reliable biomarkers that flag this silent autoimmune process early enough to permit intervention remains one of the most pressing problems in diabetology. This research analyzed the diagnostic performance of multiple autoantibody biomarkers and their combinations in predicting T1D onset among 1,247 first-degree relatives of T1D patients enrolled at two Italian university hospitals between September 2021 and March 2022. Participants underwent comprehensive autoantibody screening for glutamic acid decarboxylase 65 (GAD65), insulinoma-associated antigen 2 (IA-2), zinc transporter 8 (ZnT8), insulin autoantibodies (IAA), and islet cell antibodies (ICA), alongside HLA genotyping and serial metabolic testing including oral glucose tolerance tests and C-peptide kinetics. Of 1,247 screened individuals, 405 (32.5%) tested positive for at least one autoantibody, and 237 (19.0%) carried two or more autoantibodies with high-risk HLA genotypes. Over a median follow-up of 26 months, 89 participants (37.6% of the high-risk subgroup) progressed to clinical T1D. The composite biomarker panel combining two or more autoantibodies with HLA risk scoring achieved the highest predictive sensitivity at 0.91 for the 0-5 year age group and 0.82 for those above 30 years. IAA showed the strongest seroconversion rate in children under five (41.8%) but declined sharply in adults. GAD65 antibodies demonstrated the most consistent performance across age groups. A staged screening algorithm incorporating initial autoantibody panel, confirmatory HLA genotyping, and intensive metabolic surveillance identified 73 of 89 eventual progressors (82.0%) at a median lead time of 14.3 months before clinical onset. These findings support implementing systematic biomarker-based screening programs in at-risk populations to enable earlier identification and potential immunomodulatory intervention.

Objective: To design a dynamic prediction model for estimating the time of progression from a single glutamic acid decarboxylase autoantibody (GADA) to multiple islet autoantibodies and type 1 diabetes in children, exploring different longitudinally measured risk variables.Research Design and Methods: GADA-positive children (n = 379) participating in The Environmental Determinants of Diabetes in the Young (TEDDY) study were followed for the appearance of additional autoantibodies against either insulin autoantibody (IAA), insulinoma-like 2 autoantibody (IA-2A), or zinc transporter 8 antibody (ZnT8A) and type 1 diabetes. A dynamic prediction model was designed, including trajectories of longitudinal risk variables, autoantibody titers, and metabolic variables (C-peptide, glucose, and HbA1c) together with time-invariant variables (gender, age at GADA positivity, and high-risk HLA genotypes).Results: Transition risk from GADA to multiple autoantibodies was increased by lower age (p < 0.001) and by increased GADA titers during follow-up (p < 0.001), and was less likely in children with HLA DQ2/X but not DQ2/8 (p=0.004). The transition risk from multiple autoantibodies without IA-2A to IA-2A positivity was associated with increased levels of 2 h glucose following oral glucose tolerance test (OGTT) (p < 0.001) and increased ZnT8A titers (p < 0.001). Increasing HbA1c (p < 0.001) and GADA titers (p < 0.001) were associated with an increased risk of transition from GADA only to type 1 diabetes; while increasing HbA1c (p < 0.001) was associated with the transition from multiple autoantibodies to type 1 diabetes. Risk of transition from multiple autoantibodies, including IA-2A to type 1 diabetes was also associated with 2 h glucose level (p < 0.001).Conclusion: The dynamic prediction model presented an individual time-specific risk of transition from a single GADA to multiple autoantibodies and type 1 diabetes.

ABSTRACT Type 1 diabetes mellitus (T1D) is a complex autoimmune disease resulting from pancreatic insulin-producing cell destruction. Numerous studies have investigated the association between the Small Ubiquitin-like Modifier 4 (SUMO4) gene and the risk of T1D development. However, these findings are not consistent, particularly in non-Asian populations. This scoping review aims to comprehensively assess the association between the SUMO4 gene and TD1 in individuals of non-Asian origin. A systematic search of electronic databases was performed, including Web of Science, PubMed, Embase and Scopus. Case-control studies and prospective cohorts that provided relevant information for the association analysis were included. 6,841 articles were initially identified through database searches. After removing duplicates, 3,835 articles remained for screening. Twenty-five studies underwent full-text analysis, with nine being included in the scoping review after 16 were excluded. These studies utilized various genotyping methods, including PCR-ARMS, SSCP, RFLP, and genotyping platforms such as ILMN and SQMN. While some studies reported the male/female ratio, others focused on family studies or diabetic probands. The research was predominantly conducted in North America, Europe, Oceania, and Argentina. Across these studies, no significant evidence linking SUMO4 SNPs to T1D was found, except for marginal associations or those dependent on high-risk HLA genotype positivity. No significant association was detected between the SUMO4 gene and T1D in non-asian individuals. This finding suggests that polymorphisms in this gene might not play a substantial role in susceptibility to T1D in the investigated population.

Age at diagnosis (AAD) of Type 1 diabetes (T1D) is determined by the age at onset of the autoimmune attack and by the rate of beta cell destruction that follows. Twin studies found that T1D AAD is strongly influenced by genetics, notably in young children. In young UK, Finnish, Sardinian patients AAD-associated genomic variants were previously identified, which may vary across populations and with time. In 1956 children of European ancestry born in mainland France in 1980-2008 who declared T1D before 15 years, we tested 94 T1D-associated SNPs for their association with AAD using nonparametric Kruskal-Wallis test. While high-risk HLA genotypes were not found to be associated with AAD, fourteen SNPs located in 12 non-HLA loci showed a strong association (2.9 × 10-12 < P < 1.4 × 10-3 after FDR correction). Four of these loci have been associated with AAD in previous cohorts (GSDMB, IL2, TNFAIP3, IL1), supporting a partially shared genetic influence on AAD of T1D in the studied European populations. In contrast, the association of 8 new loci CLEC16A, TYK2, ERBB3, CCR7, FCRL3, DNAH2, FGF3/4, and HPSE2 with AAD is novel. The 12 protein-coding genes located within these loci are involved in major immune pathways or in predisposition to other autoimmune diseases, which suggests a prominent role for these genes in the early immune mechanisms of beta cell destruction.

Infections are proposed risk factors for type 1 diabetes in children. We examined whether a diagnosis of infectious disease also confers an increased risk of latent autoimmune diabetes in adults (LADA). We used data from a population-based Swedish case-control study with incident cases of LADA (n=597) and matched controls (n=2386). The history of infectious disease was ascertained through national and regional patient registers. We estimated adjusted odds ratios (OR) with 95% confidence intervals for ≥1 respiratory (any/upper/lower), gastrointestinal, herpetic, other or any infectious disease episode, or separately, for 1 and ≥2 infectious disease episodes, within 0-1, 1-3, 3-5 and 5-10years before LADA diagnosis/matching. Stratified analyses were performed on the basis of HLA risk genotypes and Glutamic acid decarboxylase antibodies (GADA) levels. Individuals who developed LADA did not have a higher prevalence of infectious disease 1-10years before diabetes diagnosis. For example, OR was estimated at 0.87 (0.66, 1.14) for any versus no respiratory infectious disease within 1-3years. Similar results were seen for LADA with high-risk HLA genotypes (OR 0.95 [0.64, 1.42]) or high GADA levels (OR 1.10 [0.79, 1.55]), ≥2 episodes (OR 0.89 [0.56, 1.40]), and in infections treated using antibiotics (OR 1.03 [0.73, 1.45]). The only significant association was observed with lower respiratory disease the year preceding LADA diagnosis (OR 1.67 [1.06, 2.64]). Our findings do not support the idea that exposure to infections increases the risk of LADA. A higher prevalence of respiratory infection in the year before LADA diagnosis could reflect increased susceptibility to infections due to hyperglycemia.

Type-1 diabetes mellitus (T1DM) is a complex multifactorial disease with an autoimmune etiology and is thought to result from an interaction between genetic and non-genetic factors. Cytokines play a crucial role in the pathogenesis of autoimmune diseases due to their effector and regulatory functions in immune responses. Interleukin-4 (IL4) and Interleukin-13 (IL13) are anti-inflammatory cytokines and are considered as important mediators in pathology of the autoimmune diseases. We have determined the genotype frequency of IL4 gene promoter polymorphism (-590C/T, rs2243250), IL13 gene polymorphism p.(Arg130Glu, rs20541) and human leukocyte antigen, HLA-DQ and DR genotypes in Kuwaiti children with T1DM to investigate their role in genetic susceptibility. This study included 261 Kuwaiti children with T1DM and 214 healthy controls. The genotypes for IL4 (-590C/T) and IL13 p.(Arg130Glu) gene polymorphisms were detected by PCR-RFLP methods. HLA-DQ and DR genotypes were determined by sequence-specific PCR methods. The CC genotype of IL4 gene polymorphism (-590C/T) was significantly related to the risk for T1DM in Kuwaiti patients (OR 1.64). The homozygous AA (QQ) and heterozygous AG (RQ) genotypes of IL13 gene polymorphism p.(Arg130Glu), also manifested a statistically significant association with T1DM (OR 2.92 and 4.79). In 55% T1DM patients, the HLA genotype was either DQ2/DQ2 or in combination with a DQ8 allele. Collectively, 91% Kuwaiti T1DM patients had either DQ2 or DQ8 alleles in different combinations highlighting them as the high risk-genotypes in comparison to the controls. In the case of HLA-DR, the genotypes DR3/DRB5, DR3/DR4, DR3/DR7 and DR4/DR4 showed highest frequency amongst the Kuwaiti T1DM patients and thus can be considered as high-risk genotypes when compared to the controls. A high degree of co-inheritance (>80%) was detected between IL4 and IL13 gene polymorphism genotypes (CC and QQ) and the high-risk HLA-DQ and DR genotypes amongst the Kuwaiti T1DM patients. We have identified the association of IL4 and IL13 gene polymorphisms with susceptibility to T1DM in Kuwaiti children and the co-inheritance of these polymorphisms with high-risk HLA genotypes. The findings may contribute to early identification of childhood diabetes.

The association between HLA genotypes and type 1 diabetes is well known. We set out to examine incidence rates and ratios of type 1 diabetes depending on the risk afflicted by HLA genotype. Children with the high-risk genotype have a 45-fold disease risk compared to peers with neutral or protective genotypes.

AimsAlterations of the exocrine pancreas have been reported in type 1 diabetes, but their contribution to the pathogenesis of the disease is poorly understood. Here, we investigated markers of exocrine pancreas dysfunction in individuals at-risk of developing type 1 diabetes.MethodsSerum P-amylase and lipase levels were assessed in samples obtained from healthy controls, patients with new onset type 1 diabetes, relatives participating to the TrialNet Pathway to Prevention who were, at blood collection, autoantibody negative or positive for a single autoantibody (low-risk individuals), and positive for multiple autoantibodies (high-risk individuals). Linear mixed models were adopted to estimate variation of pancreatic enzymes among the groups and to evaluate the influence of high-risk HLA genotypes and residual beta cell function on exocrine pancreas function.ResultsIn adults, but not children, reduced levels of P-amylase and lipase were shown in at-risk individuals, including (for P-amylase levels only) those at low-risk, and in T1Dnew. Furthermore, while high-risk HLA genotypes negatively affected P-amylase levels in autoantibody negative adult individuals, fasting C-peptide levels did not correlate with pancreatic enzyme levels.ConclusionsExocrine pancreas dysfunction precedes the onset of type 1 diabetes in adult at-risk individuals and may be unrelated to fasting C-peptide levels.

OBJECTIVEEnvironmental microbial exposures have been implicated to protect against immune-mediated diseases such as type 1 diabetes. Our objective was to study the association of land cover around the early-life dwelling with the development of islet autoimmunity and type 1 diabetes to evaluate the role of environmental microbial biodiversity in the pathogenesis.RESEARCH DESIGN AND METHODSAssociation between land cover types and the future risk of type 1 diabetes was studied by analyzing land cover types classified according to Coordination of Information on the Environment (CORINE) 2012 and 2000 data around the dwelling during the first year of life for 10,681 children genotyped for disease-associated HLA-DQ alleles and monitored from birth in the Type 1 Diabetes Prediction and Prevention (DIPP) study. Land cover was compared between children who developed type 1 diabetes (n = 271) or multiple diabetes-associated islet autoantibodies (n = 384) and children without diabetes who are negative for diabetes autoantibodies.RESULTSAgricultural land cover around the home was inversely associated with diabetes risk (odds ratio 0.37, 95% CI 0.16–0.87, P = 0.02 within a distance of 1,500 m). The association was observed among children with the high-risk HLA genotype and among those living in the southernmost study region. Snow cover on the ground seemed to block the transfer of the microbial community indoors, leading to reduced bacterial richness and diversity indoors, which might explain the regional difference in the association. In survival models, an agricultural environment was associated with a decreased risk of multiple islet autoantibodies (hazard ratio [HR] 1.60, P = 0.008) and a decreased risk of progression from single to multiple autoantibody positivity (HR 2.07, P = 0.001) compared with an urban environment known to have lower environmental microbial diversity.CONCLUSIONSThe study suggests that exposure to an agricultural environment (comprising nonirrigated arable land, fruit trees and berry plantations, pastures, natural pastures, land principally occupied by agriculture with significant areas of natural vegetation, and agroforestry areas) early in life is inversely associated with the risk of type 1 diabetes. This association may be mediated by early exposure to environmental microbial diversity.

Oxylipins are lipid mediators derived from polyunsaturated fatty acids. Some oxylipins are proinflammatory (e.g. those derived from arachidonic acid [ARA]), others are pro-resolving of inflammation (e.g. those derived from α-linolenic acid [ALA], docosahexaenoic acid [DHA] and eicosapentaenoic acid [EPA]) and others may be both (e.g. those derived from linoleic acid [LA]). The goal of this study was to examine whether oxylipins are associated with incident type 1 diabetes. We conducted a nested case-control analysis in the Diabetes Autoimmunity Study in the Young (DAISY), a prospective cohort study of children at risk of type 1 diabetes. Plasma levels of 14 ARA-derived oxylipins, ten LA-derived oxylipins, six ALA-derived oxylipins, four DHA-derived oxylipins and two EPA-related oxylipins were measured by ultra-HPLC-MS/MS at multiple timepoints related to autoantibody seroconversion in 72 type 1 diabetes cases and 71 control participants, which were frequency matched on age at autoantibody seroconversion (of the case), ethnicity and sample availability. Linear mixed models were used to obtain an age-adjusted mean of each oxylipin prior to type 1 diabetes. Age-adjusted mean oxylipins were tested for association with type 1 diabetes using logistic regression, adjusting for the high risk HLA genotype HLA-DR3/4,DQB1*0302. We also performed principal component analysis of the oxylipins and tested principal components (PCs) for association with type 1 diabetes. Finally, to investigate potential critical timepoints, we examined the association of oxylipins measured before and after autoantibody seroconversion (of the cases) using PCs of the oxylipins at those visits. The ARA-related oxylipin 5-HETE was associated with increased type 1 diabetes risk. Five LA-related oxylipins, two ALA-related oxylipins and one DHA-related oxylipin were associated with decreased type 1 diabetes risk. A profile of elevated LA- and ALA-related oxylipins (PC1) was associated with decreased type 1 diabetes risk (OR 0.61; 95% CI 0.40, 0.94). A profile of elevated ARA-related oxylipins (PC2) was associated with increased diabetes risk (OR 1.53; 95% CI 1.03, 2.29). A critical timepoint analysis showed type 1 diabetes was associated with a high ARA-related oxylipin profile at post-autoantibody-seroconversion but not pre-seroconversion. The protective association of higher LA- and ALA-related oxylipins demonstrates the importance of both inflammation promotion and resolution in type 1 diabetes. Proinflammatory ARA-related oxylipins may play an important role once the autoimmune process has begun.

AimsWe investigated the risk of latent autoimmune diabetes in adults (LADA) and type 2 diabetes in relation to a healthy lifestyle, the proportion of patients attributable to an unhealthy lifestyle, and the influence of family history of diabetes (FHD) and genetic susceptibility. MethodsThe population-based study included incident LADA (n = 571), type 2 diabetes (n = 1962), and matched controls (n = 2217). A healthy lifestyle was defined by BMI < 25 kg/m2, moderate-to-high physical activity, a healthy diet, no smoking, and moderate alcohol consumption. We estimated odds ratios (OR) with 95% confidence intervals (CIs) adjusted for age, sex, education, and FHD. ResultsCompared to a poor/moderate lifestyle, a healthy lifestyle was associated with a reduced risk of LADA (OR 0.51, CI 0.34–0.77) and type 2 diabetes (OR 0.09, CI 0.05–0.15). A healthy lifestyle conferred a reduced risk irrespective of FHD and high-risk HLA genotypes. Having a BMI < 25 kg/m2 conferred the largest risk reduction for both LADA (OR 0.54, CI 0.43–0.66) and type 2 diabetes (OR 0.12, CI 0.10–0.15) out of the individual items. ConclusionPeople with a healthy lifestyle, especially a healthy body weight, have a reduced risk of LADA including those with genetic susceptibility to diabetes.

Our aim was to elucidate the role of diet in type 1 diabetes (T1D) by examining combinations of nutrient intake in the progression from islet autoimmunity (IA) to T1D. We measured 2457 metabolites and dietary intake at the time of seroconversion in 132 IA-positive children in the prospective Diabetes Autoimmunity Study in the Young. IA was defined as the first of two consecutive visits positive for at least one autoantibody (insulin, GAD, IA-2, or ZnT8). By December 2018, 40 children progressed to T1D. Intakes of 38 nutrients were estimated from semiquantitative food frequency questionnaires. We tested the association of each metabolite with progression to T1D using multivariable Cox regression. Nutrient patterns that best explained variation in candidate metabolites were identified using reduced rank regression (RRR), and their association with progression to T1D was tested using Cox regression adjusting for age at seroconversion and high-risk HLA genotype. In stepwise selection, 22 nutrients significantly predicted at least two of the 13 most significant metabolites associated with progression to T1D, and were included in RRR. A nutrient pattern corresponding to intake lower in linoleic acid, niacin, and riboflavin, and higher in total sugars, explained 18% of metabolite variability. Children scoring higher on this metabolite-related nutrient pattern at seroconversion had increased risk for progressing to T1D (HR = 3.17, 95%CI = 1.42-7.05). Combinations of nutrient intake reflecting candidate metabolites are associated with increased risk of T1D, and may help focus dietary prevention efforts.

PurposeRed meat consumption is positively associated with type 1 (T1D) and type 2 (T2D) diabetes. We investigated if red meat consumption increases the risk of latent autoimmune diabetes in adults (LADA) and T2D, and potential interaction with family history of diabetes (FHD), HLA and TCF7L2 genotypes.MethodsAnalyses were based on Swedish case–control data comprising incident cases of LADA (n = 465) and T2D (n = 1528) with matched, population-based controls (n = 1789; n = 1553 in genetic analyses). Multivariable-adjusted ORs in relation to self-reported processed and unprocessed red meat intake were estimated by conditional logistic regression models. Attributable proportion (AP) due to interaction was used to assess departure from additivity of effects.ResultsConsumption of processed red meat was associated with increased risk of LADA (per one servings/day OR 1.27, 95% CI 1.07–1.52), whereas no association was observed for unprocessed red meat. For T2D, there was no association with red meat intake once BMI was taken into account. The combination of high (> 0.3 servings/day vs. less) processed red meat intake and high-risk HLA-DQB1 and -DRB1 genotypes yielded OR 8.05 (95% CI 4.86–13.34) for LADA, with indications of significant interaction (AP 0.53, 95% CI 0.32–0.73). Results were similar for the combination of FHD-T1D and processed red meat. No interaction between processed red meat intake and FHD-T2D or risk variants of TCF7L2 was seen in relation to LADA or T2D.ConclusionConsumption of processed but not unprocessed red meat may increase the risk of LADA, especially in individuals with FHD-T1D or high-risk HLA genotypes.

Preservation of C-peptide after diagnosis of type 1 diabetes (T1D) is associated with lower risk of both hypoglycemia and long-term microvascular complications. The decline of C-peptide after T1D onset is highly variable among subjects. The goal of this study was to evaluate factors associated with the rate of C-peptide decline. TEDDY participants identified at birth with high-risk HLA genotype and followed regularly until T1D diagnosis (n=70) and 60 age-matched children diagnosed with T1D in the community (median age at diagnosis = 6.7 years, IQR 5.1-7.9) were enrolled in a 2-year follow-up with mixed meal tolerance tests at 1, 3, 6, 12 and 24 months. Mixed effects models for repeated measures were used adjusting for age at diagnosis and C-peptide at baseline. In univariate analyses, factors associated with rate of C-peptide loss included sex, age at diagnosis, baseline BMI, AUC C-peptide, HbA1c, IA-2A positivity and ZnT8A positivity. Four of these 7 factors remained significant in multivariate analysis (all p ≤ 0.037, see Table). Younger age at diagnosis, higher HbA1c, IA-2A positivity and ZnT8A positivity were associated with higher rate of C-peptide decline in this young cohort of children diagnosed with T1D. Disclosure A. Steck: None. X. Liu: None. J. Krischer: None. M.J. Haller: Advisory Panel; Self; Pancreum, SAB Biotherapeutics. R. Veijola: None. B. Akolkar: None. J. Toppari: None. W. Hagopian: Research Support; Self; Novo Nordisk A/S. M. Rewers: None. H. Elding Larsson: None. Funding JDRF; National Institutes of Health

The risk for autoimmunity and subsequently type 1 diabetes is 10-fold higher in children with a first-degree family history of type 1 diabetes (FDR children) than in children in the general population (GP children). We analyzed children with high-risk HLA genotypes (n = 4,573) in the longitudinal TEDDY birth cohort to determine how much of the divergent risk is attributable to genetic enrichment in affected families. Enrichment for susceptible genotypes of multiple type 1 diabetes–associated genes and a novel risk gene, BTNL2, was identified in FDR children compared with GP children. After correction for genetic enrichment, the risks in the FDR and GP children converged but were not identical for multiple islet autoantibodies (hazard ratio [HR] 2.26 [95% CI 1.6–3.02]) and for diabetes (HR 2.92 [95% CI 2.05–4.16]). Convergence varied depending upon the degree of genetic susceptibility. Risks were similar in the highest genetic susceptibility group for multiple islet autoantibodies (14.3% vs .12.7%) and diabetes (4.8% vs. 4.1%) and were up to 5.8-fold divergent for children in the lowest genetic susceptibility group, decreasing incrementally in GP children but not in FDR children. These findings suggest that additional factors enriched within affected families preferentially increase the risk of autoimmunity and type 1 diabetes in lower genetic susceptibility strata.

PurposeSweetened beverage consumption is associated with type 2 diabetes (T2D) and LADA. We investigated to what extent this association is mediated by BMI and whether it is modified by genotypes of HLA, TCF7L2 rs7903146, or FTO rs9939609.MethodsSwedish case–control data including incident cases of LADA (n = 386) and T2D (n = 1253) with matched population-based controls (n = 1545) was used. We estimated adjusted ORs of diabetes (95% CI) in relation to sweetened beverage intake (per daily 200 mL serving) and genotypes. The impact of BMI was estimated using causal mediation methodology. Associations with HOMA-IR and HOMA-B were explored through linear regression.ResultsSweetened beverage intake was associated with increased risk of LADA (OR 1.15, 95% CI 1.03–1.29) and T2D (OR 1.21, 1.11–1.32). BMI was estimated to mediate 17% (LADA) and 56% (T2D) of the total risk. LADA was associated with risk variants of HLA (3.44, 2.63–4.50) and TCF7L2 (1.27, 1.00–1.61) but not FTO. Only among non-carriers of high-risk HLA genotypes was sweetened beverage intake associated with risk of LADA (OR 1.32, 1.06–1.56) and HOMA-IR (beta = 0.162, p = 0.0047). T2D was associated with TCF7L2 and FTO but not HLA, and the risk conferred by sweetened beverages appeared modified by FTO (OR 1.45, 95% CI 1.21–1.73 in non-carriers).ConclusionsOur findings suggest that sweetened beverages are associated with LADA and T2D partly through mediation by excess weight, but possibly also through other mechanisms including adverse effects on insulin sensitivity. These effects seem more pronounced in individuals without genetic susceptibility.

Coffee consumption, genetic susceptibility and risk of latent autoimmune diabetes in adults: A population-based case-control study

Most of the current understanding of type 1 diabetes (T1D) etiology and pathogenesis stemmed from studies conducted in majoritarily Non-Hispanic White (NHW) populations. However, evidence is emerging that unique mechanisms of disease may contribute to the development of T1D in individuals of Hispanic ethnicity. We reviewed the currently available literature on genetic, immunologic, metabolic and clinical characteristics of T1D in Hispanic as compared with NHW individuals. We searched PubMed, Google Scholar, and authors' bibliographies to collect information from relevant articles on the influence of ethnicity on T1D etiology and pathogenesis. There are significant epidemiological variation based on ethnicity, with consistently higher T1D incidence and prevalence rate in NHWs than Hispanics. The frequencies of T1D high-risk HLA haplotypes and genotypes, as well as their susceptibility or protective effects show considerable ethnic differences. There are conflicting data on immunologic factors (e.g. islet autoantibody positivity) and markers of beta-cell function (e.g., C-peptide levels), as well as in some clinical characteristics (e.g. frequencies of diabetic ketoacidosis and severe hypoglycemia), while age of onset is consistently similar between both groups. Higher prevalence of obesity, less intensive diabetes management, and poorer glycemic control were reported in Hispanics. Accordingly, ethnic disparities in clinical outcomes have been demonstrated as well. There are considerable differences in T1D characteristics between NHWs and Hispanics. Better insight into these ethnic differences would not only affect patient care of patients with T1D, but may also inform the design of future prediction and prevention trials.