Lifestyle or Environmental Influences and Their Interaction With Genetic Susceptibility on the Risk of LADA

Alcohol Consumption and Autoimmune Diseases

Alcohol is the second-most misused substance after tobacco. It has been identified as a causal factor in more than 200 diseases and 5.3% of all deaths and is associated with significant behavioral, social, and economic difficulties. As alcohol consumption may modulate the immune system's regulatory mechanisms to avoid attacking the body's tissues, it has been proven to play a dichotomic role in autoimmune diseases (ADs) based on the quantity of consumption. In this review, we report updated evidence on the role of alcohol in ADs, with a focus on alcohol addiction and the human biological immune system and the relationship between them, with alcohol as a risk or protective factor. Then, in this narrative review, we report the main evidence on the most studied ADs where alcohol represents a key modulator, including autoimmune thyroiditis, multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, diabetes, allergic rhinitis, and primary biliary cholangitis. Alcohol at low-moderate dosages seems mostly to have a protective role in these diseases, while at higher dosages, the collateral risks surpass possible benefits. The specific mechanisms by which low-to-moderate alcohol intake relieves AD symptoms are not yet fully understood; however, emerging studies suggest that alcohol may have a systemic immunomodulatory effect, potentially altering the balance of anti-inflammatory innate and adaptive immune cells, as well as cytokines (via the NF-κB or NLRP3 pathways). It might influence the composition of the gut microbiome (increasing amounts of beneficial gut microbes) and the production of their fatty acid metabolites, such as short-chain fatty acids (SCFAs) and polyunsaturated fatty acids (PUFAs), as well as elevated concentrations of acetate, high-density lipoprotein (HDL), and nitric oxide (NO). Unfortunately, a definite acceptable daily intake (ADI) of ethanol is complicated to establish because of the many mechanisms associated with alcohol consumption such that despite the interesting content of these findings, there is a limit to their applicability and risks should be weighed in cases of alcoholic drinking recommendations. The aim of future studies should be to modulate those beneficial pathways involved in the alcohol-protective role of ADs with various strategies to avoid the risks associated with alcohol intake.

Exposure to antibiotics and risk of latent autoimmune diabetes in adults and type 2 diabetes: results from a Swedish case-control study (ESTRID) and the Norwegian HUNT study

AIMS/HYPOTHESIS

Some studies find an increased risk of type 1 diabetes in children exposed to antibiotics. We investigated if exposure to antibiotics increases the risk of latent autoimmune diabetes in adults (LADA) and type 2 diabetes.

METHODS

We used data from a Swedish case-control study (Epidemiological Study of Risk Factors for LADA and Type 2 Diabetes [ESTRID]: LADA, n=597; type 2 diabetes, n=2065; control participants matched on participation time, n=2386) and a case-control study nested within the Norwegian Trøndelag Health Study (HUNT) (n=82/1279/2050). Anatomical Therapeutic Chemical (ATC) codes indicating antibiotic dispensations were retrieved from the Swedish National Prescribed Drug Register and Norwegian Prescription Database. Multivariable adjusted ORs with 95% CIs were estimated by conditional logistic regression and pooled using fixed-effects inverse-variance weighting.

RESULTS

We observed no increased risk of LADA with exposure to antibiotics up to 1 year (ORpooled 1.15, 95% CI 0.93, 1.41) or 1-5 years (ORpooled 0.98, 95% CI 0.80, 1.20) prior to diagnosis/matching for one or more vs no dispensation of any type of antibiotic. An increased risk was observed for one or more vs no dispensations of narrow-spectrum antibiotics, but not broad-spectrum antibiotics, 6-10 years prior to LADA diagnosis (ORpooled 1.39, 95% CI 1.01, 1.91), which was driven by the Swedish data. There was little evidence of an increased risk of type 2 diabetes associated with antibiotic exposure 1-10 years prior to diagnosis.

CONCLUSIONS/INTERPRETATION

We found no evidence that exposure to broad-spectrum antibiotics up to 10 years prior to diagnosis increases the risk of LADA. There was some indication of increased LADA risk with exposure to narrow-spectrum antibiotics, which warrants further investigation.

Early-Life Factors Associated With Adult-Onset Type 1 Diabetes: A Swedish Nationwide Cohort and Family-Based Study

OBJECTIVE

Childhood-onset type 1 diabetes (T1D) is associated with perinatal factors, but data related to adult-onset T1D are scarce. This study aimed at investigating the association between early-life factors and adult-onset T1D in a Swedish nationwide cohort and family-based study.

RESEARCH DESIGN AND METHODS

We included 1,813,415 individuals aged ≥18 years, born in Sweden 1983 to 2002, followed until 2020. T1D diagnosis (n = 3,283) was identified from the National Diabetes, Patient and Prescribed Drugs Registers, and perinatal exposures were obtained from the Medical Birth Register. We performed Cox proportional hazard (hazard ratio [95% CI]) regression with mutual adjustment for perinatal exposures, sex, birth year, and parental sociodemographic background and history of diabetes. We also compared T1D risks among siblings' groups identified from the Multiple Generation Register.

RESULTS

The incidence rate of adult-onset T1D was 18.8 per 100,000 person-years. Year of birth (1.06 [1.01-1.10], per five additional years) and history of maternal (4.10 [3.09-5.43]) and paternal (6.24 [5.10-7.64]) T1D were associated with a higher incidence of adult-onset T1D, whereas female sex (0.69 [0.64-0.74]) and having parents born outside Sweden were associated with a lower incidence. Regarding perinatal exposures, only non-full-term birth (<39 weeks vs. ≥39 weeks) was associated with a higher incidence of adult-onset T1D (1.12 [1.04-1.22]). The sibling cohort results were consistent with the full cohort analysis.

CONCLUSIONS

Perinatal factors seem to play a minor role in the development of adult-onset T1D compared with childhood-onset T1D, suggesting that triggers or accelerators of autoimmunity occurring later in life are more significant.

Phenome-Wide Association Study of Latent Autoimmune Diabetes from a Southern Mexican Population Implicates rs7305229 with Plasmatic Anti-Glutamic Acid Decarboxylase Autoantibody (GADA) Levels

Latent autoimmune diabetes in adults (LADA) is characterized by the presence of glutamate decarboxylase autoantibodies (GADA). LADA has intermediate features between type 1 diabetes and type 2 diabetes. In addition, genetic risk factors for both types of diabetes are present in LADA. Nonetheless, evidence about the genetics of LADA in non-European populations is scarce. This study aims to perform a genome-wide association study with a phenome-wide association study of LADA in a southeastern Mexican population. We included 59 patients diagnosed with LADA from a previous study and 3121 individuals without diabetes from the MxGDAR/ENCODAT database. We utilized the GENESIS package in R to perform the genome-wide association study (GWAS) of LADA and PLINK for the phenome-wide association study (PheWAS) of LADA features. Nine polymorphisms reach the nominal association level (1 × 10-5) in the GWAS. The PheWAS showed that rs7305229 is genome-wide and associated with serum GADA levels in our sample (p = 1.84 × 10-8). rs7305229 is located downstream of the FAIM2 gene; previous reports associate FAIM2 variants with childhood obesity, body mass index, body adiposity measures, lymphocyte CD8+ activity, and anti-thyroid peroxidase antibodies. Our findings reveal that rs7305229 affects the GADA levels in patients with LADA from southeastern Mexico. More studies are needed to determine if this risk genotype exists in other populations with LADA.

Prevalence of latent autoimmune diabetes in adults and insulin resistance: a systematic review and meta-analysis

Latent autoimmune diabetes in adults is a form of diabetes that progresses slowly and is controlled by diet and oral glucose-lowering medications before insulin is required. The aim of the present study was to evaluate the prevalence of latent autoimmune diabetes in adults. The present study was conducted based on PRISMA 2020-27-item checklist. To find the studies conducted in line with the purpose of the study, PubMed, Web of Science, Scopus, Science Direct, Web of Knowledge, EBSCO, Wiley, ISI, Elsevier, Embase databases and Google Scholar search engine were reviewed from 2013 to August 2023. Meta-analysis was performed using effect size with 95% confidence interval. Data analysis was done using STATA/MP. v17 software. The present study was carried out based on the PRISMA 2020 27-point checklist. To find out which studies were carried out in accordance with the purpose of the study, from 2013 to August, the databases PubMed, Web of Science, Scopus, Science Direct, Web of Knowledge, EBSCO, Wiley, ISI, Elsevier, Embase and the search engine Google Scholar reviewed 2023. Meta-analysis was performed using effect size with 95% confidence interval. Data analysis was carried out using STATA/MP. v17 software. The overall prevalence of Latent autoimmune diabetes of adults was found to be 7% (95%CI 0-20). Subgroup analysis of Latent autoimmune diabetes of adults in the context of geographic regions showed a higher prevalence in North America (15%) and South East Asia (5%). Since the identification of Latent autoimmune diabetes of adult patients with other forms of diabetes is misdiagnosed due to the combination of phenotypic features with T1D and T2D, studying its prevalence is of great importance.

Does a prior diagnosis of infectious disease confer an increased risk of latent autoimmune diabetes in adults?

AIMS

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).

MATERIALS AND METHODS

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 5-10 years before LADA diagnosis/matching. Stratified analyses were performed on the basis of HLA risk genotypes and Glutamic acid decarboxylase antibodies (GADA) levels.

RESULTS

Individuals who developed LADA did not have a higher prevalence of infectious disease 1-10 years before diabetes diagnosis. For example, OR was estimated at 0.87 (0.66, 1.14) for any versus no respiratory infectious disease within 1-3 years. 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]).

CONCLUSIONS

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.

Antioxidant Nutrients and Risk of Latent Autoimmune Diabetes in Adults and Type 2 Diabetes: A Swedish Case-Control Study and Mendelian Randomization Analysis

Antioxidant vitamins C and E are inversely associated with type 1 diabetes (T1D). We investigated if antioxidants are also associated with latent autoimmune diabetes in adults (LADA), with low (LADA^low) and high (LADA^high) autoantibody levels, type 2 diabetes (T2D), and estimates of beta cell function (HOMA-B) and insulin resistance (HOMA-IR). We used Swedish case-control data with incident cases of LADA (n = 584) and T2D (n = 1989) and matched population-based controls (n = 2276). Odds ratios (OR) and 95% confidence intervals (CI) were calculated per one standard deviation higher beta-carotene, vitamin C, vitamin E, selenium, and zinc intakes. Two-sample Mendelian randomization (MR) analyses assessed causality between genetically predicted circulating antioxidants and LADA, T1D, and T2D, using summary statistics from genome-wide association studies. Among the antioxidants, vitamins C and E were inversely associated with LADA^high (OR 0.84, CI 0.73, 0.98 and OR 0.80, CI 0.69, 0.94 respectively), but not with LADA^low or T2D. Vitamin E was also associated with higher HOMA-B and lower HOMA-IR. MR analyses estimated an OR of 0.50 (CI 0.20, 1.25) for the effect of vitamin E on T1D, but did not support causal relationships between antioxidants and either LADA or T2D. In conclusion, vitamin E may have a protective effect on autoimmune diabetes, possibly through preserved beta cell function and less insulin resistance.