Smoking, use of smokeless tobacco, HLA genotypes and incidence of latent autoimmune diabetes in adults

Causal relationships between air pollution and common autoimmune diseases: a two-sample Mendelian randomization study

Air pollution is strongly associated with autoimmune diseases (ADs), however, the genetic causality between them remains poorly understood. Therefore, the aim of this study is to determine the relationship between common air pollutants and ADs through Mendelian randomization (MR) analysis. We conducted a MR study using aggregated data from publicly available genome-wide association studies (GWAS). Single nucleotide polymorphisms (SNPs) associated with 5 common air pollutants are used as instrumental variables. Random-effects inverse variance weighted (IVW) is used as the primary method to assess causal relationships, with results reported in terms of odds ratios (OR). In addition, we used a two-step MR to assess the mediating role of common risk factors for ADs in the effects of air pollution on ADs. Our analysis revealed causal associations between selected air pollutants and specific ADs. Exposure to nitrogen oxides was positively associated with the risk of rheumatoid arthritis (RA) (OR = 1.47,95% CI 1.01-2.14, P = 0.043), Sjogren's syndrome (SS) (OR = 2.29,95% CI 1.08-4.89, P = 0.032), and systemic lupus erythematosus (OR = 7.26,95% CI 2.25-23.40, P = 9.10E-04). Genetically predicted PM2.5 and PM10 were risk factors for ulcerative colitis (OR = 1.68,95% CI 1.05-2.68, P = 0.032) and psoriasis (OR = 1.34,95% CI 1.02-1.76, P = 0.037), respectively. Our results also suggest a negative causal relationship between PM2.5-10 and SS (OR = 0.29, 95% CI 0.10-0.90, P = 0.032). In risk factor-related mediation analyses, BMI and smoking mediated 6% (95% CI 1-10%) and 9% (95% CI 2-17%) of the effect of nitrogen oxides on RA, respectively. This study provides evidence of a causal relationship between air pollutants and specific ADs risks, suggesting that improving air pollution may be important in preventing ADs.

Associations of classical HLA alleles with sleep behaviours

Immune dysregulation has been observed in individuals with sleep disturbance, with HLA molecules play a crucial role in the immune response. This study aimed to investigate the associations between HLA alleles and sleep behaviours, considering several environmental factors. Data were sourced from the UK Biobank. Logistic regression analyses were performed to explore the associations between 359 HLA alleles and 4 sleep behaviours, including chronotype (n = 204,636), insomnia (n = 227,553), snoring (n = 214,350) and daytime dozing (n = 227,197). Furthermore, gene-environmental interaction studies (GEIS) were conducted to evaluate the interactions of HLA alleles with environmental factors on sleep behaviours. This study analysed a total sample and subgroups stratified by sex to elucidate the impact of HLA alleles on sleep behaviours. Our findings revealed several associations between specific HLA alleles and sleep behaviours. Notably, HLA-A*23:01 was associated with evening chronotype in the total sample (OR = 0.918, 95%CI: 0.872-0.965), while HLA-A*32:01 was associated with evening chronotype in males (OR = 1.089, 95%CI: 1.037-1.144). Furthermore, GEIS identified multiple sets of interactions associated with sleep behaviours. For example, the interaction of HLA-DPA1*01:04 with alcohol consumption was associated with daytime dozing in the total sample (OR = 1.993, 95%CI: 1.351-2.941), while the interaction of HLA-DQB1*05:04 with ever suffered mental distress preventing usual activities was associated with insomnia in males (OR = 0.409, 95%CI: 0.254-0.658). Our findings highlight the involvement of HLA in sleep regulation and underscore the potential interactions between HLA alleles and environmental factors in modulating susceptibility to sleep behaviours.

An online tool using clinical factors to estimate the probability of partial clinical remission of adult-onset Type 1 diabetes

A type 1 diabetes (T1D) diagnosis is often followed by a period of reduced exogenous insulin requirement, with acceptable glucose control, called partial clinical remission (pCR). Various criteria exist to define pCR, which is associated with better clinical outcomes. We aimed to develop formulae and a related online calculator to predict the probability of pCR at 3- and 12-months post-T1D diagnosis. We analysed data from 133 adults at their T1D diagnosis (mean ± SD age: 27 ± 6 yrs., HbA1c 11.1 ± 2.0 %, 98 ± 22 mmol/mol), 3- and 12-months later. All patients were enrolled in the prospective observational InLipoDiab1 study (NCT02306005). We compared four definitions of pCR: 1) stimulated C-peptide >300 pmol/l; 2) insulin dose-adjusted HbA1c ≤9 %; 3) insulin dose <0.3 IU/kg/24 h; and HbA1c ≤6.4 % (46 mmol/mol); and 4) insulin dose <0.5 IU/kg/24 h and HbA1c <7 % (53 mmol/mol). Using readily available demographics and clinical chemistry data exhaustive search methodology was used to model pCR probability. There was low concordance between pCR definitions (kappa 0.10). The combination of age, HbA1c, diastolic blood pressure, triglycerides and smoking at T1D onset predicted pCR at 12-months with an area under the curve (AUC) = 0.87. HbA1c, triglycerides and insulin dose 3-mths post-diagnosis had an AUC = 0.89. A related calculator for pCR in adult-onset T1D is available at http://www.bit.ly/T1D-partial-remission.

Impact of Smokeless Tobacco on Cardiovascular Disease Risk in a Nigerian Metropolitan City

The use of smokeless tobacco products (STP) as a substitute for tobacco smoking is driving increasing consumption of these products especially in developing countries. The study sought to make comparison of cardiovascular risk profile between chronic STP users and suitably matched tobacco-naïve controls. This is a preliminary report from the cross sectional part of a two-arm prospective study of Smokeless Tobacco Products Composition and Exposure Outcome in Enugu metropolis, Nigeria. Consecutively recruited current Smokeless tobacco users, who had no history of cigarette smoking, aged 18 years and above, residing in selected communities in Enugu metropolis, Nigeria were recruited for the study from October 2022 to July 2023. Age and sex matched non-tobacco users from same localities as the study subjects served as controls. Written informed consent to participate in the study was obtained from all study participants. All participants were screened by the investigators, using the study case report forms, to obtain data on medical history, demographic, clinical, laboratory, and electrocardiographic evaluation. Data from 54 STP-users and 54 non-STP-users (mean age 56.58 ± 8.15 years) were analyzed. Anthropometric parameters were similar in both groups. Smokeless tobacco users had higher erect and supine blood pressure indices as well as greater postural drop in systolic blood pressure. The occurrence of diabetes mellitus (20.37% versus 5.56%) and hypertension (25.93%; 11.11%) was significantly higher in the STP-users than in the non-user population, (p = 0.02192 and 0.04751 respectively). Electrocardiographic evaluation showed significantly increased QTc and dispersions of P-wave, QRS and QT intervals as well as reduced PR interval in STP users. Electrocardiographic abnormalities observed in STP users include left ventricular hypertrophy, left atrial enlargement, ST-segment elevation, short PR interval and long QTc. Use of smokeless tobacco products is associated with increased risk burden of diabetes mellitus and hypertensive heart disease. Electrocardiographic findings linked to STP-use in this study are features consistent with arrhythmia, ventricular repolarization abnormality, myocardial hypertrophy and ischaemia, suggesting that smokeless tobacco products are not safe substitutes for tobacco smoking.

Novel Therapeutic Agents for Management of Diabetes Mellitus: A Hope for Drug Designing against Diabetes Mellitus

Diabetes mellitus (DM) is characterized by an absolute decline in insulin secretion and peripheral resistance and is the most prevalent metabolic and endocrine disorder. However, the pathogenesis of DM also includes adipocyte insulin resistance, increased glucagon secretion, increased renal glomerular glucose absorption, and neurotransmitter dysfunction. Although there is a wide spectrum of therapeutics available for glycemic control, owing to the identification of various pathogenic determinants of DM, management of DM remains challenging and complex. Current therapeutic interventions against DM focus mostly on glycemic control without considering the other pathological determinants that eventually lead to treatment failure and the progression of DM. Furthermore, long-term use of these conventionally available anti-diabetic drugs leads to various side effects, henceforth development of novel drugs against DM remains an unending search strategy for researchers. Various studies conducted in various parts of the world have proposed that these novel therapeutic interventions target multiple and alternate pathogenic hotspots involved in DM. The current review article discusses novel therapeutic options that hold particular promise to support their safety and discuss the side effects resulting from their use so that these novel candidate drugs can be effectively fabricated into potential drugs for the treatment of DM.

Prenatal and adult exposure to smoking and incidence of type 1 diabetes in children and adults-a nationwide cohort study with a family-based design

Background

Prenatal exposure to smoking is linked to a reduced risk of type 1 diabetes in children. We wanted to find out if the risk of adult-onset type 1 diabetes is reduced in individuals who are exposed to smoking prenatally or during adulthood.

Methods

We linked Swedish, nationwide registers and prospectively analyzed incidence of type 1 diabetes in relation to maternal smoking during pregnancy and adult smoking. Everyone was followed until age 30 or year 2019. We employed cohort and sibling design and used adjusted Cox regression and conditional logistic regression.

Findings

For analyses of maternal smoking there were 3,170,386 individuals (18,745 cases of type 1 diabetes) and for adult smoking 1,608,291 individuals (1274 cases). Prenatal exposure to smoking was associated with lower incidence of type 1 diabetes during childhood and young adulthood (age 20-24, Hazard ratio (HR) 0.76, 95% Confidence interval 0.67-0.87), but not at higher ages. The HR associated with adult smoking was estimated at 1.14 (CI 1.00-1.31) overall and 1.34 (CI 1.03-1.75) in those with family history of diabetes. In sibling analyses, the odds ratio (OR) of type 1 diabetes in relation to prenatal exposure was 0.71 (CI 0.62-0.81) in children and 1.06 (CI 0.75-1.51) in adults (age 19-30), while adult smoking conferred an OR of 1.59 (CI 1.08-2.35).

Interpretation

These findings indicate that a reduced risk conferred by tobacco exposure is limited to the prenatal period and type 1 diabetes developing during childhood. Adult smoking may be a risk factor for adult-onset type 1 diabetes, especially in people with family history of diabetes.

Funding

Swedish Research Councils, Swedish Diabetes and Novo Nordisk Foundations, China Scholarship Council.

Evaluation of the Relationship Between Smoking and Insulin Resistance: A Case-Control Study

Introduction: In recent years, there has been a surge in research focusing on the link between smoking and insulin resistance in the context of obesity and diabetes. In this study, our objective was to investigate the relationship between smoking and insulin resistance.

Materials and Methods: This is a case-control study. The case and control groups were formed using the hospital patient information database and clinically randomized using data obtained, including age, gender, height, and weight. The case group for this study consisted of smokers, whereas the control group consisted of non-smokers. Chi-square tests were used to compare numbers and rates, and independent sample t-tests were used for the averages. Binary logistic regression analysis was performed between the case and control groups.

Results: According to logistic regression analysis, the odds ratio for non-smokers was 0.59 (0.31-1.14). The risk of insulin resistance is decreased by 41% non-significantly in non-smokers. The odds ratio for age was 1.03 (1.01-1.05). When the age variable increases by one unit, the risk of insulin resistance increase by 1.03 times.

Conclusion: Our study found no significant relationship between smoking and insulin resistance in healthy individuals. The relationship between smoking and insulin resistance, as reported in the scientific literature, may be suggestive of an association in which smoking exacerbates insulin resistance as a result of other contributing factors rather than serving as a direct causal factor. Further studies are warranted to elucidate the potential mechanisms underlying this association fully.