Vitamins C, E, and β-Carotene and Risk of Type 2 Diabetes: A Systematic Review and Meta-Analysis

A systematic review and meta-analysis was conducted to assess the relationship between the common dietary antioxidants vitamin C, vitamin E, and β-carotene and type 2 diabetes (T2D) and related traits. MEDLINE, Embase, and the Cochrane Library were searched for relevant publications up until May 2023. Studies were eligible if they had a cohort, case-control, or randomized controlled trial (RCT) design and examined dietary intake, supplementation, or circulating levels of these antioxidants as exposure, and insulin resistance, β-cell function, or T2D incidence as outcomes. Summary relative risks (RR) or mean differences (MD) with 95% confidence intervals (CI) were estimated using random-effects models. The certainty of the evidence was assessed with the Grading of Recommendations, Assessment, Development and Evaluations framework. Among 6190 screened records, 25 prospective observational studies and 15 RCTs were eligible. Inverse associations were found between dietary and circulating antioxidants and T2D (observational studies). The lowest risk was seen at intakes of 70 mg/d of vitamin C (RR: 0.76; CI: 0.61, 0.95), 12 mg/d of vitamin E (RR: 0.72; CI: 0.61, 0.86), and 4 mg/d of β-carotene (RR: 0.78; CI: 0.65, 0.94). Supplementation with vitamin E (RR: 1.01; CI: 0.93, 1.10) or β-carotene (RR: 0.98; CI: 0.90, 1.07) did not have a protective effect on T2D (RCTs), and data on vitamin C supplementation was limited. Regarding insulin resistance, higher dietary vitamin C (RR: 0.85; CI: 0.74, 0.98) and vitamin E supplementation (MD: -0.35; CI: -0.65, -0.06) were associated with a reduced risk. The certainty of evidence was high for the associations between T2D and dietary vitamin E and β-carotene, and low to moderate for other associations. In conclusion, moderate intakes of vitamins C, E, and β-carotene may lower risk of T2D by reducing insulin resistance. Lack of protection with supplementation in RCTs suggests that adequate rather than high intakes may play a role in T2D prevention. This systematic review and meta-analysis was registered in PROSPERO with registration number CRD42022343482.

Familial aggregation and heritability of childhood-onset and adult-onset type 1 diabetes: a Swedish register-based cohort study

BACKGROUND

Type 1 diabetes in children is known to be highly heritable, but much less is known about the heritability of adult-onset type 1 diabetes. Thus, our objective was to compare the familial aggregation and heritability of type 1 diabetes in adults and children.

METHODS

This Swedish nationwide register-based cohort study included individuals born from Jan 1, 1982, to Dec 31, 2010, identified through the Medical Birth Register who were linked to their parents, full siblings, half siblings, and cousins through the Multi-Generation Register (MGR). We excluded multiple births, deaths within the first month of life, individuals who could not be linked to MGR, or individuals with contradictory information on sex. Information on diagnoses of type 1 diabetes was retrieved by linkages to the National Diabetes Register and National Patient Register (1982-2020). Individuals with inconsistent records of diabetes type were excluded. We estimated the cumulative incidence and hazard ratios (HRs) of type 1 diabetes in adults (aged 19-30 years) and children (aged 0-18 years) by family history of type 1 diabetes and the heritability of adult-onset and childhood-onset type 1 diabetes based on tetrachoric correlations, using sibling pairs.

FINDINGS

2 943 832 individuals were born in Sweden during the study period, 2 832 755 individuals were included in the analysis of childhood-onset type 1 diabetes and 1 805 826 individuals were included in the analysis of adult-onset type 1 diabetes. 3240 cases of adult-onset type 1 diabetes (median onset age 23·4 years [IQR 21·1-26·2]; 1936 [59·7%] male and 1304 [40·2%] female) and 17 914 cases of childhood-onset type 1 diabetes (median onset age 9·8 years [6·2-13·3]; 9819 [54·8%] male and 8095 [45·2%] female) developed during follow-up. Having a first-degree relative with type 1 diabetes conferred an HR of 7·21 (95% CI 6·28-8·28) for adult-onset type 1 diabetes and 9·92 (9·38-10·50) for childhood-onset type 1 diabetes. The HR of developing type 1 diabetes before the age 30 years was smaller if a first-degree relative developed type 1 diabetes during adulthood (6·68 [6·04-7·39]) rather than during childhood (10·54 [9·92-11·19]). Similar findings were observed for type 1 diabetes in other relatives. Heritability was lower for adult-onset type 1 diabetes (0·56 [0·45-0·66]) than childhood-onset type 1 diabetes (0·81 [0·77-0·85]).

INTERPRETATION

Adult-onset type 1 diabetes seems to have weaker familial aggregation and lower heritability than childhood-onset type 1 diabetes. This finding suggests a larger contribution of environmental factors to the development of type 1 diabetes in adults than in children and highlights the need to identify and intervene on such factors.

FUNDING

Swedish Research Council, the Swedish Research Council for Health, Working Life and Welfare, Swedish Diabetes Foundation, and the China Scholarship Council.

Decreasing lifetime prevalence of diabetes-related foot ulcers in Norway: repeated cross-sectional population-based surveys from the HUNT study (1995-2019)

Background and aims

Diabetes-related foot ulcers (DFU) are a persistent healthcare challenge, impacting both patients and healthcare systems, with adverse effects on quality of life and productivity. Our primary aim was to examine the trends in lifetime prevalence of DFU, as well as other micro- and macrovascular complications in the Trøndelag Health Study (HUNT) in Norway.

Methods

This study consists of individuals ≥20 years with diabetes participating in the population-based cross-sectional HUNT surveys (1995-2019). Prevalence ratios, comparing the lifetime prevalence of DFU and other relevant micro- and macrovascular complications between the HUNT surveys, were calculated using Poisson regression.

Results

The lifetime prevalence (95% confidence interval (CI)) of a DFU requiring three or more weeks to heal was 11.0% (9.5-12.7) in HUNT2, 7.5% (6.3-8.8) in HUNT3 and 5.3% (4.4-6.3) in HUNT4. The decrease in DFU prevalence from 1995 to 2019 was observed in both men and women, for all age groups, and for both type 1 and type 2 diabetes. The highest lifetime prevalence of DFU was found among those with type 1 diabetes. The decrease in HbA1c from HUNT2 to HUNT4 did not differ between those with and without a DFU. The prevalence of chronic kidney disease (eGFR <60 mL/min/1.73 m2 (eGFR categories G3-G5)) increased in both individuals with and without a DFU.

Conclusion

Results from the HUNT surveys show a substantial decline in the lifetime prevalence of DFU from 1995 to 2019.

Metabolic profiling of smoking, associations with type 2 diabetes and interaction with genetic susceptibility

BACKGROUND

Smokers are at increased risk of type 2 diabetes (T2D), but the underlying mechanisms are unclear. We investigated if the smoking-T2D association is mediated by alterations in the metabolome and assessed potential interaction with genetic susceptibility to diabetes or insulin resistance.

METHODS

In UK Biobank (n = 93,722), cross-sectional analyses identified 208 metabolites associated with smoking, of which 131 were confirmed in Mendelian Randomization analyses, including glycoprotein acetyls, fatty acids, and lipids. Elastic net regression was applied to create a smoking-related metabolic signature. We estimated hazard ratios (HR) of incident T2D in relation to baseline smoking/metabolic signature and calculated the proportion of the smoking-T2D association mediated by the signature. Additive interaction between the signature and genetic risk scores for T2D (GRS-T2D) and insulin resistance (GRS-IR) on incidence of T2D was assessed as relative excess risk due to interaction (RERI).

FINDINGS

The HR of T2D was 1·73 (95% confidence interval (CI) 1·54 - 1·94) for current versus never smoking, and 38·3% of the excess risk was mediated by the metabolic signature. The metabolic signature and its mediation role were replicated in TwinGene. The metabolic signature was associated with T2D (HR: 1·61, CI 1·46 - 1·77 for values above vs. below median), with evidence of interaction with GRS-T2D (RERI: 0·81, CI: 0·23 - 1·38) and GRS-IR (RERI 0·47, CI: 0·02 - 0·92).

INTERPRETATION

The increased risk of T2D in smokers may be mediated through effects on the metabolome, and the influence of such metabolic alterations on diabetes risk may be amplified in individuals with genetic susceptibility to T2D or insulin resistance.

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.

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.

Type, Etiology, and Duration of Epilepsy as Risk Factors for SUDEP: Further Analyses of a Population-Based Case-Control Study

BACKGROUND AND OBJECTIVES

We conducted a nationwide case-control study in Sweden to investigate the risk of sudden unexpected death in epilepsy (SUDEP) in relation to epilepsy duration, epilepsy type, and etiology in combination with occurrence and frequency of tonic-clonic seizures (TCS) and nocturnal TCS.

METHODS

The study comprised 255 SUDEP cases and 1,148 epilepsy controls. Clinical information was obtained from medical records. The association between SUDEP and risk factors was estimated by odds ratios (ORs) with 95% CIs calculated by conditional logistic regression to account for matching by sex and calendar time.

RESULTS

The risk of SUDEP was elevated in people with focal (OR 1.48, 95% CI 1.00-2.20), generalized and focal (OR 3.51, 95% CI 1.55-7.96), or unknown (OR 2.43, 95% CI 1.29-4.57) vs generalized epilepsy type. Increased risk of SUDEP was also observed in relation to epilepsy with traumatic causes (OR 2.27, 95% CI 1.33-3.89 vs genetic etiology) or short duration (OR 1.71, 95% CI 1.01-2.87 for 0-5 vs 6-15 years duration). Among those with 1-3 TCS during the preceding year, structural epilepsy etiology was associated with a more than 10-fold increase 10.84 (4.85-24.27) in SUDEP risk compared with people with genetic epilepsy without TCS. The risk with ≥4 TCS the preceding year was similar among those with generalized and focal epilepsies. Those with ≥4 TCS had an OR of 210.73 (95% CI 28.40-∞) during years 0-5 compared with those free from TCS and an epilepsy duration of 6-15 years. The combination of short epilepsy duration (0-5 years) and nocturnal TCS conferred an OR of 45.99 (95% CI 12.19-173.61) compared with having longer duration (6-15 years) and being free from nocturnal TCS.

DISCUSSION

Although certain etiologies, such as post-traumatic epilepsy, seem to entail a higher SUDEP risk, our data indicate that frequent and nocturnal TCS carry a similar level of risk whether focal or generalized from onset. The tonic-clonic part of the seizure seems to be decisive for the fatal outcome. SUDEP risk associated with TCS is highest during the first years after the epilepsy diagnosis which calls for effective TCS treatment and vigilance from the onset of diagnosis.

All-Cause Mortality and Cardiovascular and Microvascular Diseases in Latent Autoimmune Diabetes in Adults

OBJECTIVE

Latent autoimmune diabetes in adults (LADA) is a heterogenous, slowly progressing autoimmune diabetes. We aim to contribute new knowledge on the long-term prognosis of LADA with varying degrees of autoimmunity by comparing it to type 2 diabetes and adult-onset type 1 diabetes.

RESEARCH DESIGN AND METHODS

This Swedish population-based study included newly diagnosed LADA (n = 550, stratified into LADAlow and LADAhigh by median autoimmunity level), type 2 diabetes (n = 2,001), adult-onset type 1 diabetes (n = 1,573), and control subjects without diabetes (n = 2,355) in 2007-2019. Register linkages provided information on all-cause mortality, cardiovascular diseases (CVDs), diabetic retinopathy, nephropathy, and clinical characteristics during follow-up.

RESULTS

Mortality was higher in LADA (hazard ratio [HR] 1.44; 95% CI 1.03, 2.02), type 1 (2.31 [1.75, 3.05]), and type 2 diabetes (1.31 [1.03, 1.67]) than in control subjects. CVD incidence was elevated in LADAhigh (HR 1.67; 95% CI 1.04, 2.69) and type 2 diabetes (1.53 [1.17, 2.00]), but not in LADAlow or type 1 diabetes. Incidence of retinopathy but not nephropathy was higher in LADA (HR 2.25; 95% CI 1.64, 3.09), including LADAhigh and LADAlow than in type 2 diabetes (unavailable in type 1 diabetes). More favorable blood pressure and lipid profiles, but higher HbA1c levels, were seen in LADA than type 2 diabetes at baseline and throughout follow-up, especially in LADAhigh, which resembled type 1 diabetes in this respect.

CONCLUSIONS

Despite having fewer metabolic risk factors than type 2 diabetes, LADA has equal to higher risks of death, CVD, and retinopathy. Poorer glycemic control, particularly in LADAhigh, highlights the need for improved LADA management.

Interaction between plasma phospholipid odd-chain fatty acids and GAD65 autoantibodies on the incidence of adult-onset diabetes: the EPIC-InterAct case-cohort study

AIMS/HYPOTHESIS

Islet autoimmunity may progress to adult-onset diabetes. We investigated whether circulating odd-chain fatty acids (OCFA) 15:0 and 17:0, which are inversely associated with type 2 diabetes, interact with autoantibodies against GAD65 (GAD65Ab) on the incidence of adult-onset diabetes.

METHODS

We used the European EPIC-InterAct case-cohort study including 11,124 incident adult-onset diabetes cases and a subcohort of 14,866 randomly selected individuals. Adjusted Prentice-weighted Cox regression estimated HRs and 95% CIs of diabetes in relation to 1 SD lower plasma phospholipid 15:0 and/or 17:0 concentrations or their main contributor, dairy intake, among GAD65Ab-negative and -positive individuals. Interactions between tertiles of OCFA and GAD65Ab status were estimated by proportion attributable to interaction (AP).

RESULTS

Low concentrations of OCFA, particularly 17:0, were associated with a higher incidence of adult-onset diabetes in both GAD65Ab-negative (HR 1.55 [95% CI 1.48, 1.64]) and GAD65Ab-positive (HR 1.69 [95% CI 1.34, 2.13]) individuals. The combination of low 17:0 and high GAD65Ab positivity vs high 17:0 and GAD65Ab negativity conferred an HR of 7.51 (95% CI 4.83, 11.69), with evidence of additive interaction (AP 0.25 [95% CI 0.05, 0.45]). Low dairy intake was not associated with diabetes incidence in either GAD65Ab-negative (HR 0.98 [95% CI 0.94, 1.02]) or GAD65Ab-positive individuals (HR 0.97 [95% CI 0.79, 1.18]).

CONCLUSIONS/INTERPRETATION

Low plasma phospholipid 17:0 concentrations may promote the progression from GAD65Ab positivity to adult-onset diabetes.

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.

Performance of a System for Rapid Phenotypic Antimicrobial Susceptibility Testing of Gram-Negative Bacteria Directly from Positive Blood Culture Bottles

The rapid administration of optimal antimicrobial treatment is paramount for the treatment of bloodstream infections (BSIs), and rapid antimicrobial susceptibility testing (AST) results are essential. Q-linea has developed the ASTar system, a rapid phenotypic AST device. Here, we report the performance of the ASTar BC G- (Gram-negative) kit when assessed according to the ISO 20776-2:2007 standard for performance evaluation of in vitro diagnostic AST devices. The evaluated ASTar BC G- kit uses a broad panel of 23 antimicrobials for the treatment of BSIs caused by Gram-negative fastidious and nonfastidious bacteria across a range of 6 to 14 2-fold dilutions, including cefoxitin as a screening agent for AmpC-producing Enterobacterales. The ASTar system processes blood culture samples to generate data on MICs and susceptible, intermediate, or resistant (SIR) category. The automated protocol includes concentration determination and concentration adjustment to enable a controlled inoculum, followed by broth microdilution (BMD) and microscopy performed continuously to generate MIC values within approximately 6 h once the test is run on the ASTar system. The performance of the ASTar system was assessed against the ISO 20776-2:2007 standard BMD reference method. Testing was performed across three sites, with results from 412 contrived blood cultures and 74 fresh clinical blood cultures. The ASTar system was also tested for reproducibility, with triplicate testing of 11 strains. The accuracy study comprised 8,650 data points of bacterium-antimicrobial tests. The ASTar system demonstrated an overall essential agreement (EA) of 95.8% (8,283/8,650) and a categorical agreement (CA) of 97.6% (8,433/8,639) compared to the reference BMD method. The overall rate of major discrepancies (MDs) was 0.9% (62/6,845), and that of very major discrepancies (VMDs) was 2.4% (30/1,239). This study shows that the ASTar system delivers reproducible results with overall EA and CA of >95%.

Incidence of LADA and Type 2 Diabetes in Relation to Tobacco Use and Genetic Susceptibility to Type 2 Diabetes and Related Traits: Findings From a Swedish Case-Control Study and the Norwegian HUNT Study

OBJECTIVE

Smoking and Swedish smokeless tobacco (snus) are associated with latent autoimmune diabetes in adults (LADA) and type 2 diabetes (T2D). Our aim was to investigate whether genetic susceptibility to T2D, insulin resistance (IR), and insulin secretion (IS) aggravate these associations.

RESEARCH DESIGN AND METHODS

We used data from two population-based Scandinavian studies with case subjects with LADA (n = 839) and T2D (n = 5,771), matched control subjects (n = 3,068), and 1,696,503 person-years at risk. Pooled, multivariate relative risks (RR) with 95% CI were estimated for smoking/genetic risk scores (T2D-GRS, IS-GRS, and IR-GRS), and ORs for snus or tobacco/GRS (case-control data). We estimated additive (proportion attributable to interaction [AP]) and multiplicative interaction between tobacco use and GRS.

RESULTS

The RR of LADA was elevated in high IR-GRS heavy smokers (≥15 pack-years; RR 2.01 [CI 1.30, 3.10]) and tobacco users (≥15 box/pack-years; RR 2.59 [CI 1.54, 4.35]) compared with low IR-GRS individuals without heavy use, with evidence of additive (AP 0.67 [CI 0.46, 0.89]; AP 0.52 [CI 0.21, 0.83]) and multiplicative (p = 0.003; p = 0.034) interaction. In heavy users, there was additive interaction between T2D-GRS and smoking, snus, and total tobacco use. The excess risk conferred by tobacco use did not differ across GRS categories in T2D.

CONCLUSIONS

Tobacco use may confer a higher risk of LADA in individuals with genetic susceptibility to T2D and insulin resistance, whereas genetic susceptibility does not seem to influence the increased T2D incidence associated with tobacco use.

Childhood adiposity and novel subtypes of diabetes in adults: a Mendelian randomisation and genome-wide genetic correlation study

BACKGROUND

Five novel subtypes of adult-onset diabetes were identified in 2018. We aimed to investigate whether childhood adiposity increases the risks of these subtypes using a Mendelian randomisation design, and to explore genetic overlaps between body size (self-reported perceived body size [ie, thinner, about average, or plumper] in childhood, and BMI measured in adulthood) and these subtypes.

METHODS

The Mendelian randomisation and genetic correlation analyses were based on summary statistics from European genome-wide association studies of childhood body size (n=453 169), adult BMI (n=359 983), latent autoimmune diabetes in adults (n=8581), severe insulin-deficient diabetes (n=3937), severe insulin-resistant diabetes (n=3874), mild obesity-related diabetes (n=4118), and mild age-related diabetes (n=5605). We identified 267 independent genetic variants as instrumental variables for childhood body size in the Mendelian randomisation analysis of latent autoimmune diabetes in adults and 258 independent genetic variants as instrumental variables for other diabetes subtypes. The inverse variance-weighted method was used as the primary estimator in the Mendelian randomisation analysis, supplemented by other Mendelian randomisation estimators. We calculated overall genetic correlations (rg) between childhood or adult adiposity and different subtypes using linkage disequilibrium score regression.

FINDINGS

A large childhood body size was associated with increased risk of latent autoimmune diabetes in adults (odds ratio [OR] 1·62, 95% CI 1·95-2·52), severe insulin-deficient diabetes (OR 2·45, 1·35-4·46), severe insulin-resistant diabetes (OR 3·08, 1·73-5·50), and mild obesity-related diabetes (OR 7·70, 4·32-13·7), but not mild age-related diabetes in the main Mendelian randomisation analysis. Other Mendelian randomisation estimators gave similar results and did not support the existence of horizontal pleiotropy. There was genetic overlap between childhood body size and mild obesity-related diabetes (rg 0·282; p=0·0003), and between adult BMI and all diabetes subtypes.

INTERPRETATION

This study provides genetic evidence that higher childhood adiposity is a risk factor for all subtypes of adult-onset diabetes, except mild age-related diabetes. It is therefore important to prevent and intervene in childhood overweight or obesity. There is shared genetic contribution to childhood obesity and mild obesity-related diabetes.

FUNDING

The study was supported by the China Scholarship Council, the Swedish Research Council (grant number 2018-03035), Research Council for Health, Working Life and Welfare (grant number 2018-00337), and Novo Nordisk Foundation (grant number NNF19OC0057274).

Childhood adiposity and novel subtypes of adult-onset diabetes: a Mendelian randomisation and genome-wide genetic correlation study

AIMS/HYPOTHESIS

We investigated whether the impacts of childhood adiposity on adult-onset diabetes differ across proposed diabetes subtypes using a Mendelian randomisation (MR) design.

METHODS

We performed MR analysis using data from European genome-wide association studies of childhood adiposity, latent autoimmune diabetes in adults (LADA, proxy for severe autoimmune diabetes), severe insulin-deficient diabetes (SIDD), severe insulin-resistant diabetes (SIRD), mild obesity-related diabetes (MOD) and mild age-related diabetes (MARD).

RESULTS

Higher levels of childhood adiposity had positive genetically predicted effects on LADA (OR 1.62, 95% CI 1.05, 2.52), SIDD (OR 2.11, 95% CI 1.18, 3.80), SIRD (OR 2.76, 95% CI 1.60, 4.75) and MOD (OR 7.30, 95% CI 4.17, 12.78), but not MARD (OR 1.06, 95% CI 0.70, 1.60).

CONCLUSIONS/INTERPRETATION

Childhood adiposity is a risk factor not only for adult-onset diabetes primarily characterised by obesity or insulin resistance, but also for subtypes primarily characterised by insulin deficiency or autoimmunity. These findings emphasise the importance of preventing childhood obesity.

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

AIMS/HYPOTHESES

Smoking and use of smokeless tobacco (snus) are associated with an increased risk of type 2 diabetes. We investigated whether smoking and snus use increase the risk of latent autoimmune diabetes in adults (LADA) and elucidated potential interaction with HLA high-risk genotypes.

METHODS

Analyses were based on Swedish case-control data (collected 2010-2019) with incident cases of LADA (n=593) and type 2 diabetes (n=2038), and 3036 controls, and Norwegian prospective data (collected 1984-2019) with incident cases of LADA (n=245) and type 2 diabetes (n=3726) during 1,696,503 person-years of follow-up. Pooled RRs with 95% CIs were estimated for smoking, and ORs for snus use (case-control data only). The interaction was assessed by attributable proportion (AP) due to interaction. A two-sample Mendelian randomisation (MR) study on smoking and LADA/type 2 diabetes was conducted based on summary statistics from genome-wide association studies.

RESULTS

Smoking (RR_pooled 1.30 [95% CI 1.06, 1.59] for current vs never) and snus use (OR 1.97 [95% CI 1.20, 3.24] for ≥15 box-years vs never use) were associated with an increased risk of LADA. Corresponding estimates for type 2 diabetes were 1.38 (95% CI 1.28, 1.49) and 1.92 (95% CI 1.27, 2.90), respectively. There was interaction between smoking and HLA high-risk genotypes (AP 0.27 [95% CI 0.01, 0.53]) in relation to LADA. The positive association between smoking and LADA/type 2 diabetes was confirmed by the MR study.

CONCLUSIONS/INTERPRETATION

Our findings suggest that tobacco use increases the risk of LADA and that smoking acts synergistically with genetic susceptibility in the promotion of LADA.

DATA AVAILABILITY

Analysis codes are shared through GitHub ( https://github.com/jeseds/Smoking-use-of-smokeless-tobacco-HLA-genotypes-and-incidence-of-LADA ).

Perinatal risk factors for SUDEP: A population-based case-control study

Sudden unexpected death in epilepsy (SUDEP) is a leading epilepsy-related cause of death. Researchers have highlighted the similarities between SUDEP and sudden infant death syndrome (SIDS), but perinatal risk factors such as those identified for SIDS have not been assessed previously for SUDEP. We conducted a population-based case-control study of 58 SUDEP individuals and 384 living epilepsy controls born after 1982, utilizing the Swedish Medical Birth Register together with other national health registers and individual medical records to examine if prenatal and perinatal factors are associated with SUDEP risk. We observed a 3-fold SUDEP risk increase for infants who were small for gestational age (SGA) (odds ratio [OR] 3.13; 95% confidence interval [CI] 1.05-9.30) and for those with an Apgar score of 0-6 compared to 9-10 at 10 min (OR 3.22; 95% CI 1.05-9.87). After adjusting for a number of known SUDEP risk factors, we observed that the Apgar score between 0 and 6 after 10 min had a 10-fold increased risk for SUDEP OR 10.37 (95% CI 1.49-72.01) and over a 2-fold risk for those born after the 40th gestational week (OR 2.42; 95% CI 1.03-5.65). The potential mechanisms linking low Apgar score, gestational age, and SGA to SUDEP risk remain to be explored.

Birthweight, BMI in adulthood and latent autoimmune diabetes in adults: a Mendelian randomisation study

AIMS/HYPOTHESIS

Observational studies have found an increased risk of latent autoimmune diabetes in adults (LADA) associated with low birthweight and adult overweight/obese status. We aimed to investigate whether these associations are causal, using a two-sample Mendelian randomisation (MR) design. In addition, we compared results for LADA and type 2 diabetes.

METHODS

We identified 43 SNPs acting through the fetal genome as instrumental variables (IVs) for own birthweight from a genome-wide association study (GWAS) of the Early Growth Genetics Consortium (EGG) and the UK Biobank. We identified 820 SNPs as IVs for adult BMI from a GWAS of the UK Biobank and the Genetic Investigation of ANthropometric Traits consortium (GIANT). Summary statistics for the associations between IVs and LADA were extracted from the only GWAS involving 2634 cases and 5947 population controls. We used the inverse-variance weighted (IVW) estimator as our primary analysis, supplemented by a series of sensitivity analyses.

RESULTS

Genetically determined own birthweight was inversely associated with LADA (OR per SD [~500 g] decrease in birthweight 1.68 [95% CI 1.01, 2.82]). In contrast, genetically predicted BMI in adulthood was positively associated with LADA (OR per SD [~4.8 kg/m2] increase in BMI 1.40 [95% CI 1.14, 1.71]). Robust results were obtained in a range of sensitivity analyses using other MR estimators or excluding some IVs. With respect to type 2 diabetes, the association with birthweight was not stronger than in LADA while the association with adult BMI was stronger than in LADA.

CONCLUSIONS/ INTERPRETATION

This study provides genetic support for a causal link between low birthweight, adult overweight/obese status and LADA.

Maternal smoking during pregnancy and type 1 diabetes in the offspring: a nationwide register-based study with family-based designs

BACKGROUND

Maternal smoking during pregnancy was reported to be associated with a reduced risk of type 1 diabetes in the offspring. We investigated whether this association is consistent with a causal interpretation by accounting for familial (shared genetic and environmental) factors using family-based, quasi-experimental designs.

METHODS

We included 2,995,321 children born in Sweden between 1983 and 2014 and followed them for a diagnosis of type 1 diabetes until 2020 through the National Patient, Diabetes and Prescribed Drug Registers. Apart from conducting a traditional cohort study, we performed a nested case-control study (quasi-experiment) comparing children with type 1 diabetes to their age-matched siblings (or cousins). Information on maternal smoking during pregnancy was retrieved from the Swedish Medical Birth Register. Multivariable adjusted Cox proportional hazards regression and conditional logistic regression were used.

RESULTS

A total of 18,617 children developed type 1 diabetes, with a median age at diagnosis of 9.4 years. The sibling and cousin comparison design included 14,284 and 7988 of these children, respectively. Maternal smoking during pregnancy was associated with a 22% lower risk of offspring type 1 diabetes in the full cohort (hazard ratio 0.78, 95% confidence interval [CI] 0.75-0.82). The corresponding odds ratio was 0.78 (95% CI 0.69-0.88) in the sibling and 0.72 (95% CI 0.66-0.79) in the cousin comparison analysis.

CONCLUSIONS

This nationwide, family-based study provides support for a protective effect of maternal smoking on offspring type 1 diabetes. Mechanistic studies are needed to elucidate the underlying pathways behind this link.

Parental smoking, type 1 diabetes, and islet autoantibody positivity in the offspring: A systematic review and meta-analysis

AIMS

Our aim was to synthesize current evidence on the association between parental smoking and incidence of type 1 diabetes and islet autoantibody positivity (IA) in the offspring by conducting a systematic review and meta-analysis.

METHODS

We searched Medline, Embase, and Cochrane Library until January 21, 2021, for human studies with parental tobacco use as exposure, type 1 diabetes or IA as outcome, and hazard, risk, or odds ratios as effect estimates. Summary relative risks (RR) and 95% confidence intervals (CI) were estimated with random-effects models. Heterogeneity was quantified with the I²  statistic, bias with the ROBINS-I tool, and the certainty of evidence with the GRADE tool.

RESULTS

We identified 535 records of which 23 were eligible including 25 927 cases of type 1 diabetes. Maternal smoking during pregnancy was associated with a reduced risk of type 1 diabetes (n = 22, RR 0.78, CI 0.71-0.86, I² =69%). Including only studies with low to moderate risk of bias indicated similar results with less heterogeneity (n = 14, RR 0.73, CI 0.68-0.79, I²  = 44%). The certainty of evidence was graded as high. There was no clear association between type 1 diabetes and neither maternal (n = 6, RR 0.95, CI 0.78-1.14, I²  = 0%) nor paternal (n = 6, RR 0.90, 0.70-1.17, I²  = 68%) smoking during childhood. Furthermore, the association between maternal smoking during pregnancy and IA was weak (n = 4, RR 0.86, CI 0.44-1.65, I²  = 71%).

CONCLUSIONS

Maternal smoking during pregnancy may reduce the risk of type 1 diabetes in the offspring. Further studies are needed to elucidate potential mechanisms underlying this association.

REGISTRATION

Prospero CRD42021236717.

Alterations in Biomarkers Related to Glycemia, Lipid Metabolism, and Inflammation up to 20 Years Before Diagnosis of Type 1 Diabetes in Adults: Findings From the AMORIS Cohort

OBJECTIVE

Type 1 diabetes is described to have an acute onset, but autoantibodies can appear several years preceding diagnosis. This suggests a long preclinical phase, which may also include metabolic parameters. Here we assessed whether elevations in glycemic, lipid, and other metabolic biomarkers were associated with future type 1 diabetes risk in adults.

RESEARCH DESIGN AND METHODS

We studied 591,239 individuals from the Swedish AMORIS cohort followed from 1985-1996 to 2012. Through linkage to national patient, diabetes, and prescription registers, we identified incident type 1 diabetes. Using Cox regression models, we estimated hazard ratios for biomarkers at baseline and incident type 1 diabetes. We additionally assessed trajectories of biomarkers during the 25 years before type 1 diabetes diagnosis in a nested case-control design.

RESULTS

We identified 1,122 type 1 diabetes cases during follow-up (average age of patient at diagnosis: 53.3 years). The biomarkers glucose, fructosamine, triglycerides, the ratio of apolipoprotein (apo)B to apoA-I, uric acid, alkaline phosphatase, and BMI were positively associated with type 1 diabetes risk. Higher apoA-I was associated with lower type 1 diabetes incidence. Already 15 years before diagnosis, type 1 diabetes cases had higher mean glucose, fructosamine, triglycerides, and uric acid levels compared with control subjects.

CONCLUSIONS

Alterations in biomarker levels related to glycemia, lipid metabolism, and inflammation are associated with clinically diagnosed type 1 diabetes risk, and these may be elevated many years preceding diagnosis.

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

BACKGROUND

LADA is a common form of diabetes described as a mix between type 1 and type 2 diabetes. Understanding of how genes and environmental factors interact in the development of LADA is central for future efforts to prevent the disease. This review aims to synthesize the literature on lifestyle factors linked to LADA risk and discuss their potential interaction with genetic susceptibility.

FINDINGS

Current knowledge on environmental risk factors for LADA is primarily based on observational data from Scandinavian populations. Increasing evidence suggest that lifestyle factors promoting type 2 diabetes such as obesity, sedentariness, low birth weight and smoking, is implicated in the risk of LADA. Data from mendelian randomization studies support that the link between LADA and obesity, low birth weight and smoking is causal. Limited evidence indicates that dietary factors including consumption of red meat, coffee and sweetened beverages may increase the risk while consumption of alcohol and omega-3 fatty acids may reduce the risk. Several lifestyle factors, including smoking and obesity, seem to interact with human leukocyte antigen genes associated with autoimmunity, conferring much stronger effects on disease risk among those exposed to both factors.

SUMMARY

Available studies suggest that lifestyle modification has the potential for prevention of LADA, particularly for individuals with high risk of disease such as those with genetic susceptibility. Research into risk factors of LADA is however limited, confirmations are warranted, many factors remain to be explored, and there is a need for intervention studies to assess causality.

Genome-wide association analyses highlight etiological differences underlying newly defined subtypes of diabetes

Type 2 diabetes has been reproducibly clustered into five subtypes with different disease progression and risk of complications; however, etiological differences are unknown. We used genome-wide association and genetic risk score (GRS) analysis to compare the underlying genetic drivers. Individuals from the Swedish ANDIS (All New Diabetics In Scania) study were compared to individuals without diabetes; the Finnish DIREVA (Diabetes register in Vasa) and Botnia studies were used for replication. We show that subtypes differ with regard to family history of diabetes and association with GRS for diabetes-related traits. The severe insulin-resistant subtype was uniquely associated with GRS for fasting insulin but not with variants in the TCF7L2 locus or GRS reflecting insulin secretion. Further, an SNP (rs10824307) near LRMDA was uniquely associated with mild obesity-related diabetes. Therefore, we conclude that the subtypes have partially distinct genetic backgrounds indicating etiological differences.

Dietary factors and risk of islet autoimmunity and type 1 diabetes: a systematic review and meta-analysis

Background

Numerous dietary components have been linked to the development of islet autoimmunity (IA) and type 1 diabetes (T1D); however, no associations are firmly established. This systematic review and meta-analysis aimed to synthesize current knowledge on diet and incidence of IA and T1D.

Methods

Literature search was performed in Medline, Embase, and Cochrane Library, from inception until October 2020. Eligible studies had IA or T1D as outcome; any dietary exposure; case-control, cohort, or randomized controlled trial design; and hazard, risk, or odds ratios as measures of association. Summary relative risks (RR) and 95% confidence intervals (CI) were estimated with random-effects models. Certainty of evidence was assessed with GRADE. PROSPERO registration number: CRD42020212505.

Findings

Among 5935 identified records, 96 were eligible, and pooled estimates could be produced for 26 dietary factors. Evidence with moderate/high certainty indicated lower risk of T1D in relation to longer (≥6-12 vs <6-12 months, RR: 0⋅39, CI: 0⋅26-0⋅58, I²=43%) and exclusive (≥2-3 vs <2-3 months, RR: 0⋅68, CI: 0⋅58-0⋅80, I²=0%) breastfeeding, later introduction to gluten (3-6 vs <3-5 months, RR: 0⋅36, CI: 0⋅17-0⋅75, I²=0%), cow's milk (≥2-3 vs <2-3 months, RR: 0⋅69, CI: 0⋅59-0⋅81, I²=0%), and fruit (4-6 vs <4-5 months, RR: 0⋅47, CI: 0⋅25-0⋅86, I²=0%). Higher childhood intake of cow's milk was associated with increased risk of both IA (per 2-3 portions/day, RR: 1⋅25, CI: 1⋅06-1⋅47, I²=0%) and T1D (≥2-3 vs <2-3 glasses/day, RR: 1⋅81, CI: 1⋅12-2⋅91, I²=31%). For the remaining dietary factors investigated, there was no association, or the evidence was of low certainty.

Interpretation

This study suggests that breastfeeding and late introduction of gluten, fruit, and cow's milk may reduce the risk of T1D, whereas high childhood cow's milk intake may increase it.

Funding

Swedish Research Council, Swedish Research Council for Health, Working Life and Welfare (FORTE), Novo Nordisk Foundation, and Swedish Diabetes Foundation.

Mortality rates and cardiovascular disease burden in type 2 diabetes by occupation, results from all Swedish employees in 2002-2015

Objective

To identify occupations where employees with type 2 diabetes have a high risk of cardiovascular disease (CVD) and mortality, and their prevalence of CVD risk factors. This study can contribute in the creation of targeted interventions at the workplace.

Research design and methods

This nationwide registry-based study included all employees with type 2 diabetes born in Sweden in 1937–1979 (n = 180,620) and followed up in 2002–2015. We calculated age-standardized incidence (per 100,000 person-years) of all-cause and CVD mortality, ischemic heart disease (IHD) and stroke across the 30 most common occupations. Information on prognostic factors was retrieved from the National Diabetes Register.

Results

In males with type 2 diabetes, mortality rates were highest in manufacturing workers (1782) and machine operators (1329), and lowest in specialist managers (633). The risk of death at age 61–70 years was 21.8% in manufacturing workers and 8.5% in managers. In females with type 2 diabetes, mortality rates were highest in manufacturing workers (1150) and cleaners (876), and lowest in writers and artists (458); the risk of death at age 61–70 years was 12.4% in manufacturing workers and 4.3% in writers and artists. The same occupations also had relatively high incidences of CVD mortality, IHD and stroke. Occupational groups with poor prognosis had high prevalence of CVD risk factors including poor glycemic control, smoking and obesity.

Conclusions

Manufacturing workers, machine operators and cleaners with type 2 diabetes have two to three times higher mortality rates than managers, writers and artists with type 2 diabetes. Major health gains would be made if targeted workplace interventions could reduce CVD risk factors in these occupations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-021-01320-8.

Combined lifestyle factors and the risk of LADA and type 2 diabetes - Results from a Swedish population-based case-control study

AIMS

We 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.

METHODS

The 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.

RESULTS

Compared 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.

CONCLUSION

People with a healthy lifestyle, especially a healthy body weight, have a reduced risk of LADA including those with genetic susceptibility to diabetes.

Interaction Between GAD65 Antibodies and Dietary Fish Intake or Plasma Phospholipid n-3 Polyunsaturated Fatty Acids on Incident Adult-Onset Diabetes: The EPIC-InterAct Study

OBJECTIVE

Islet autoimmunity is associated with diabetes incidence. We investigated whether there was an interaction between dietary fish intake or plasma phospholipid n-3 polyunsaturated fatty acid (PUFA) concentration with the 65-kDa isoform of GAD (GAD65) antibody positivity on the risk of developing adult-onset diabetes.

RESEARCH DESIGN AND METHODS

We used prospective data on 11,247 incident cases of adult-onset diabetes and 14,288 noncases from the EPIC-InterAct case-cohort study conducted in eight European countries. Baseline plasma samples were analyzed for GAD65 antibodies and phospholipid n-3 PUFAs. Adjusted hazard ratios (HRs) for incident diabetes in relation to GAD65 antibody status and tertiles of plasma phospholipid n-3 PUFA or fish intake were estimated using Prentice-weighted Cox regression. Additive (proportion attributable to interaction [AP]) and multiplicative interactions between GAD65 antibody positivity (≥65 units/mL) and low fish/n-3 PUFA were assessed.

RESULTS

The hazard of diabetes in antibody-positive individuals with low intake of total and fatty fish, respectively, was significantly elevated (HR 2.52 [95% CI 1.76-3.63] and 2.48 [1.79-3.45]) compared with people who were GAD65 antibody negative and had high fish intake, with evidence of additive (AP 0.44 [95% CI 0.16-0.72] and 0.48 [0.24-0.72]) and multiplicative (P = 0.0465 and 0.0103) interactions. Individuals with high GAD65 antibody levels (≥167.5 units/mL) and low total plasma phospholipid n-3 PUFAs had a more than fourfold higher hazard of diabetes (HR 4.26 [2.70-6.72]) and an AP of 0.46 (0.12-0.80) compared with antibody-negative individuals with high n-3 PUFAs.

CONCLUSIONS

High fish intake or relative plasma phospholipid n-3 PUFA concentrations may partially counteract the increased diabetes risk conferred by GAD65 antibody positivity.

The anatomical SP-CL stem demonstrates a non-progressing migration pattern in the first year: a low dose CT-based migration study in 20 patients

Background and purpose - RSA is the gold standard for evaluation of early implant migration. We report the results of a new CT-based method Sectra CT micromotion analysis (CTMA) applied to assess the migration pattern in 20 patients in the 1st year after surgery, both with and without the use of tantalum beads in the bone. The patients had an SP-CL anatomical stem that uses an S-shape, designed to better fit the curvature of the femur. Patients and methods - 20 THA patients (mean age 61 years, 10 female) received SP-CL stems, tantalum markers in the femur, and low-dose CT scans at 1 day, 3 months and 12 months postoperatively. In addition, precision as well as inter- and intra-observer variability of the 12-month migration was measured. Results - The 3-month subsidence was median 0.5 mm (95% CI 0.3-1.0) and the internal rotation 1.8° (CI 0.9-2.6). At 12 months the corresponding values were 0.6 (CI 0.3-1.6) mm and 1.9° (CI 0.8-2.4). Precision was 0.1 to 0.3 mm and 0.1° to 0.4° at 3 and 12 months. Intra- and inter- observer variability yielded R-values averaging 0.96 and 0.98. Interpretation - The migration mainly took place during the 1st 3 months, in line with other uncemented stems. The number of patients with subsidence over 2 mm in the first year (5) might be due to the design of the prosthesis with an anatomical shape. Alternatively, our results might indicate a challenge when choosing the correct size for these new anatomical stems. CTMA provided precise and highly repeatable measurements of migration without the need for tantalum markers.

Physical Activity, Genetic Susceptibility, and the Risk of Latent Autoimmune Diabetes in Adults and Type 2 Diabetes

PURPOSE

Physical activity (PA) has been linked to a reduced risk of type 2 diabetes by reducing weight and improving insulin sensitivity. We investigated whether PA is associated with a lower incidence of latent autoimmune diabetes in adults (LADA) and whether the association is modified by genotypes of human leukocyte antigen (HLA), transcription factor 7-like 2 (TCF7L2)-rs7903146, or the fat mass and obesity-associated gene, FTO-rs9939609.

METHODS

We combined data from a Swedish case-control study and a Norwegian prospective study including 621 incident cases of LADA and 3596 cases of type 2 diabetes. We estimated adjusted pooled relative risks (RRs) and 95% CI of diabetes in relation to high (≥ 30 minutes of moderate activity 3 times/week) self-reported leisure time PA, compared to sedentariness.

RESULTS

High PA was associated with a reduced risk of LADA (RR 0.61; CI, 0.43-0.86), which was attenuated after adjustment for body mass index (BMI) (RR 0.90; CI, 0.63-1.29). The reduced risk applied only to noncarriers of HLA-DQB1 and -DRB1 (RR 0.49; CI, 0.33-0.72), TCF7L2 (RR 0.62; CI, 0.45-0.87), and FTO (RR 0.51; CI, 0.32-0.79) risk genotypes. Adjustment for BMI attenuated but did not eliminate these associations. For type 2 diabetes, there was an inverse association with PA (RR 0.49; CI, 0.42-0.56), irrespective of genotype.

MAIN CONCLUSIONS

Our findings indicate that high PA is associated with a reduced risk of LADA in individuals without genetic susceptibility.

Pharmacologic treatment and SUDEP risk: A nationwide, population-based, case-control study

Objective

We conducted a nationwide case–control study in Sweden to test the hypothesis that antiepileptic drugs (AEDs) mono- or polytherapy, adherence, antidepressants, neuroleptics, β-blockers, and statins are associated with sudden unexpected death in epilepsy (SUDEP) risk.

Methods

Included were 255 SUDEP cases and 1,148 matched controls. Information on clinical factors and medications came from medical records and the National Patient and Prescription Registers. The association between SUDEP and medications was assessed by odds ratios (ORs) with 95% confidence intervals (CIs) adjusted for potential risk factors including type of epilepsy, living conditions, comorbidity, and frequency of generalized tonic-clonic seizures (GTCS).

Results

Polytherapy, especially taking 3 or more AEDs, was associated with a substantially reduced risk of SUDEP (OR 0.31, 95% CI 0.14–0.67). Combinations including lamotrigine (OR 0.55, 95% CI 0.31–0.97), valproic acid (OR 0.53, 95% CI 0.29–0.98), and levetiracetam (OR 0.49, 95% CI 0.27–0.90) were associated with reduced risk. No specific AED was associated with increased risk. Regarding monotherapy, although numbers were limited, the lowest SUDEP risk was seen in users of levetiracetam (0.10, 95% CI 0.02–0.61). Having nonadherence mentioned in the medical record was associated with an OR of 2.75 (95% CI 1.58–4.78). Statin use was associated with a reduced SUDEP risk (OR 0.34, 95% CI 0.11–0.99) but selective serotonin reuptake inhibitor use was not.

Conclusion

These results provide support for the importance of medication adherence and intensified AED treatment for patients with poorly controlled GTCS in the effort to reduce SUDEP risk and suggest that comedication with statins may reduce risk.

Epilepsy syndromes, etiologies, and the use of next-generation sequencing in epilepsy presenting in the first 2 years of life: A population-based study

OBJECTIVE

Population-based data on epilepsy syndromes and etiologies in early onset epilepsy are scarce. The use of next-generation sequencing (NGS) has hitherto not been reported in this context. The aim of this study is to describe children with epilepsy onset before 2 years of age, and to explore to what degree whole exome and whole genome sequencing (WES/WGS) can help reveal a molecular genetic diagnosis.

METHODS

Children presenting with a first unprovoked epileptic seizure before age 2 years and registered in the Stockholm Incidence Registry of Epilepsy (SIRE) between September 1, 2001 and December 31, 2006, were retrieved and their medical records up to age 7 years reviewed. Children who met the epilepsy criteria were included in the study cohort. WES/WGS was offered in cases of suspected genetic etiology regardless of whether a structural or metabolic diagnosis had been established.

RESULTS

One hundred sixteen children were included, of which 88 had seizure onset during the first year of life and 28 during the second, corresponding to incidences of 139 and 42/100 000 person-years, respectively. An epilepsy syndrome could be diagnosed in 54% of cases, corresponding to a birth prevalence of 1/1100. Structural etiology was revealed in 34% of cases, a genetic cause in 20%, and altogether etiology was known in 65% of children. The highest diagnostic yield was seen in magnetic resonance imaging (MRI) with 65% revealing an etiology. WES/WGS was performed in 26/116 cases (22%), with a diagnostic yield of 58%.

SIGNIFICANCE

Epilepsy syndromes can be diagnosed and etiologies revealed in a majority of early onset cases. NGS can identify a molecular diagnosis in a substantial number of children, and should be included in the work-up, especially in cases of epileptic encephalopathy, cerebral malformation, or metabolic disease without molecular diagnosis. A genetic diagnosis is essential to genetic counselling, prenatal diagnostics, and precision therapy.

Consumption of red meat, genetic susceptibility, and risk of LADA and type 2 diabetes

Purpose

Red 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.

Methods

Analyses 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.

Results

Consumption 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.

Conclusion

Consumption of processed but not unprocessed red meat may increase the risk of LADA, especially in individuals with FHD-T1D or high-risk HLA genotypes.

Electronic supplementary material

The online version of this article (10.1007/s00394-020-02285-2) contains supplementary material, which is available to authorized users.

Incidence and prevalence of type 2 diabetes by occupation: results from all Swedish employees

AIMS/HYPOTHESIS

The workplace is a potentially important arena for prevention of type 2 diabetes and the first step is to identify occupations where the disease is common and/or risk is high. Therefore, our aim was to analyse incidence and prevalence of type 2 diabetes across all occupational groups in Sweden.

METHODS

This nationwide study included all Swedish citizens born between 1937 and 1979 and gainfully employed between 2001 and 2013 (N = 4,550,892), and followed for a diagnosis of diabetes from 2006 to 2015 (n = 201,717) through national registers. Prevalence in 2013 (mean age 51 years; range 35-67) and age-standardised incidence (per 1000 person-years) were analysed across the 30 most common occupations among men and women. Information on BMI, physical fitness and smoking was obtained through the National Conscription (mean age 18) and Medical Birth Registers (mean age 29).

RESULTS

Prevalence of type 2 diabetes was 5.2% in men and 3.2% in women; in men it was highest among motor vehicle drivers (8.8%) and in women it was highest among manufacturing workers (6.4%). Incidence varied dramatically across occupational groups. In men, it was highest among manufacturing workers (9.41) and professional drivers (9.32) and lowest among university teachers (3.44). In women, incidence was highest in manufacturing workers (7.20) and cleaners (6.18) and lowest in physiotherapists (2.20). We found major differences in the prevalence of being overweight and smoking and in the level of physical fitness across these occupational groups even at young ages.

CONCLUSIONS/INTERPRETATION

Professional drivers, manufacturing workers and cleaners have a threefold increased risk of type 2 diabetes compared with university teachers and physiotherapists. These differences most likely reflect dramatic differences in the prevalence of lifestyle risk factors. If workplace interventions could reduce weight and increase physical activity among employees in these occupations, major health gains may be made.

Clinical risk factors in SUDEP: A nationwide population-based case-control study

Objective

We conducted a nationwide case-control study in Sweden to test the hypothesis that specific clinical characteristics are associated with increased risk of sudden unexpected death in epilepsy (SUDEP).

Methods

The study included 255 SUDEP cases (definite and probable) and 1,148 matched controls. Clinical information was obtained from medical records and the National Patient Register. The association between SUDEP and potential risk factors was assessed by odds ratios (ORs) and 95% confidence intervals (CIs) and interaction assessed by attributable proportion due to interaction (AP).

Results

Experiencing generalized tonic-clonic seizures (GTCS) during the preceding year was associated with a 27-fold increased risk (OR 26.81, 95% CI 14.86–48.38), whereas no excess risk was seen in those with exclusively non-GTCS seizures (OR 1.15, 95% CI 0.54–48.38). The presence of nocturnal GTCS during the last year of observation was associated with a 15-fold risk (OR 15.31, 95% CI 9.57–24.47). Living alone was associated with a 5-fold increased risk of SUDEP (OR 5.01, 95% CI 2.93–8.57) and interaction analysis showed that the combination of not sharing a bedroom and having GTCS conferred an OR of 67.10 (95% CI 29.66–151.88), with AP estimated at 0.69 (CI 0.53–0.85). Among comorbid diseases, a previous diagnosis of substance abuse or alcohol dependence was associated with excess risk of SUDEP.

Conclusions

Individuals with GTCS who sleep alone have a dramatically increased SUDEP risk. Our results indicate that 69% of SUDEP cases in patients who have GTCS and live alone could be prevented if the patients were not unattended at night or were free from GTCS.

Interaction Between Overweight and Genotypes of HLA, TCF7L2, and FTO in Relation to the Risk of Latent Autoimmune Diabetes in Adults and Type 2 Diabetes

OBJECTIVE

We investigated potential interactions between body mass index (BMI) and genotypes of human leukocyte antigen (HLA), TCF7L2-rs7903146, and FTO-rs9939609 in relation to the risk of latent autoimmune diabetes in adults (LADA) and type 2 diabetes.

METHODS

We pooled data from two population-based studies: (i) a Swedish study with incident cases of LADA [positive for glutamic acid decarboxylase autoantibodies (GADA); n = 394) and type 2 diabetes (negative for GADA; n = 1290) and matched controls without diabetes (n = 2656) and (ii) a prospective Norwegian study that included incident cases of LADA (n = 131) and type 2 diabetes (n = 1901) and 886,120 person-years of follow-up. Analyses were adjusted for age, sex, physical activity, and smoking. Interaction between overweight (BMI ≥ 25 kg/m2) and HLA/TCF7L2/FTO high-risk genotypes was assessed by attributable proportion due to interaction (AP).

RESULTS

The combination of overweight and high-risk genotypes of HLA, TCF7L2, and FTO was associated with pooled relative risk (RRpooled) of 7.59 (95% CI, 5.27 to 10.93), 2.65 (95% CI, 1.97 to 3.56), and 2.21 (95% CI, 1.60 to 3.07), respectively, for LADA, compared with normal-weight individuals with low/intermediate genetic risk. There was a significant interaction between overweight and HLA (AP, 0.29; 95% CI, 0.10 to 0.47), TCF7L2 (AP, 0.31; 95% CI, 0.09 to 0.52), and FTO (AP, 0.38; 95% CI, 0.15 to 0.61). The highest risk of LADA was seen in overweight individuals homozygous for the DR4 genotype [RR, 26.76 (95% CI, 15.42 to 46.43); AP, 0.58 (95% CI, 0.32 to 0.83) (Swedish data)]. Overweight and TCF7L2 also significantly interacted in relation to type 2 diabetes (AP, 0.26; 95% CI, 0.19 to 0.33), but no interaction was observed with high-risk genotypes of HLA or FTO.

CONCLUSIONS

Overweight interacts with HLA high-risk genotypes but also with genes associated with type 2 diabetes in the promotion of LADA.

Tobacco and type 2 diabetes: is the association explained by genetic factors?

BACKGROUND

Smoking and use of Swedish smokeless tobacco (snus) are associated with increased risk of type 2 diabetes (T2D). Our aim was to estimate the unique and shared genetic components of these traits and to what extent the association is explained by shared genetic factors.

METHODS

We used twins of the Swedish Twin Registry who responded to a questionnaire between 1998 and 2006 (n = 40 247) and were followed until 2015 in the National Prescription and Patient Registries. We estimated hazard ratios (HRs) and odds ratios (ORs) for the association between smoking/snus use and T2D (n = 2130) and used structural equation models to estimate genetic and environmental variance components and genetic correlations.

RESULTS

Current smokers [HR 1.69, 95% confidence interval (CI), 1.49-1.92] and snus users (HR 1.19, 95% CI 1.01-1.41) had an increased risk of T2D. In within-pair analyses of monozygotic twins, corresponding ORs were 1.36, 95% CI 0.75-2.46 (smoking) and 1.54, 95% CI 0.80-2.99 (snus). Heritability was 43% (95% CI 36-51) for ever smoking, 58% (95% CI 44- 70) for ever snus use and 66% (95% CI 59-72) for T2D. The genetic correlation with T2D was 18% (95% CI 1-35) for smoking and -6% (95% CI -24 to 4) for snus use, indicating that only a small fraction of the genetic influence is shared.

CONCLUSIONS

We could confirm that consumers of snus and cigarettes are at increased risk of T2D. Both snus use and smoking have strong genetic components, which appears to be attributable primarily to genes that are distinct from those promoting T2D.

Etiology and Pathogenesis of Latent Autoimmune Diabetes in Adults (LADA) Compared to Type 2 Diabetes

As the heterogeneity of diabetes is becoming increasingly clear, opportunities arise for more accurate assessment of factors influencing disease onset, which may lead to more efficient primary prevention. LADA - latent autoimmune diabetes in adults - is a common, hybrid form of diabetes with features of both type 1 and type 2 diabetes. This review aims to summarize current knowledge on the pathophysiological and etiological overlap and differences between LADA and type 2 diabetes, discuss similarities between LADA and type 1 diabetes and point at future research needs. Studies conducted to date show a clear genetic overlap between LADA and type 1 diabetes with a high risk conferred by variants in the human leukocyte antigen (HLA) region. In contrast, data from the limited number of studies on lifestyle factors available indicate that LADA may share several environmental risk factors with type 2 diabetes including overweight, physical inactivity, alcohol consumption (protective) and smoking. These factors are known to influence insulin sensitivity, suggesting that insulin resistance, in addition to insulin deficiency due to autoimmune destruction of the beta cells, may play a key role in the pathogenesis of LADA. Moreover, this implies that onset of LADA, similar to type 2 diabetes, to some extent could be prevented or postponed by lifestyle modification such as weight reduction and increased physical activity. The preventive potential of LADA is an important topic to elucidate in future studies, preferably intervention studies.

Environmental (Lifestyle) Risk Factors for LADA

BACKGROUND

In order to prevent diabetes it is important to identify common, modifiable risk factors in the population. Such knowledge is extensive for type 2 diabetes but limited for autoimmune forms of diabetes.

OBJECTIVE

This review aims at summarizing the limited literature on potential environmental (lifestyle) risk factors for LADA.

METHODS

A PubMed search identified 15 papers estimating the risk of LADA in relation to lifestyle. These were based on data from two population-based studies; one Swedish case-control study and one Norwegian cohort study.

RESULTS

Studies published to date indicate that the risk of LADA is associated with factors promoting insulin resistance and type 2 diabetes such as overweight, physical inactivity, smoking, low birth weight, sweetened beverage intake and moderate alcohol consumption (protective). Findings also indicate potential effects on autoimmunity exerted by intake of coffee (harmful) and fatty fish (protective). This supports the concept of LADA as being a hybrid form of diabetes with an etiology including factors associated with both insulin resistance and autoimmunity.

CONCLUSION

LADA may in part be preventable through the same lifestyle modifications as type 2 diabetes including weight loss, physical activity and smoking cessation. However, current knowledge is hampered by the small number of studies and the fact that they exclusively are based on Scandinavian populations. There is a great need for additional studies exploring the role of lifestyle factors in the development of LADA.

Antithrombotic Effect of Two Low Molecular Weight Thrombin Inhibitors and a Low-Molecular Weight Heparin in a Caval Vein Thrombosis Model in the Rat

A sensitive thrombosis model with a high reproducibility was developed in the rat, utilizing stasis of the caval vein and a standardized surgical trauma as the only thrombogenic stimuli. Since no procoagulant substances were used, the results of the present study might be relevant in a clinical situation. The antithrombotic effect of two recently synthesized low-molecular-weight thrombin inhibitors have been compared to dalteparin, (Fragmin) a low-molecular-weight heparin fragment. Each compound was studied at 8 different doses with 10 rats in each group. On a gravimetric basis, the thrombin inhibitor melagatran was twice as potent as dalteparin (ED50 16 and 33 µ/kg per h, respectively). The second thrombin inhibitor, inogatran, had an intermediate effect, with an ED50 of 24 µLg/kg per h. No differences in antithrombotic effect were, however, found when the compounds were compared at anticoagulant equivalent doses (same APTT prolongation). A 50% reduction in the mean thrombus weight was obtained when APTT was prolonged to 1.2 to 1.3 times the pretreatment value.