C. de Block

Beta-cell, thyroid, gastric, adrenal and coeliac autoimmunity and HLA-DQ types in type 1 diabetes

The autoimmune attack in type 1 diabetes is not only targeted to β cells. We assessed the prevalence of thyroid peroxidase (aTPO), parietal cell (PCA), antiadrenal (AAA) and endomysial antibodies (EmA‐IgA), and of overt autoimmune disease in type 1 diabetes, in relation to gender, age, duration of disease, age at onset, β‐cell antibody status (ICA, GADA, IA2A) and HLA‐DQ type. Sera from 399 type 1 diabetic patients (M/F: 188/211; mean age: 26 ± 16 years; duration: 9 ± 8 years) were tested for ICA, PCA, AAA and EmA‐IgA by indirect immunofluorescence, and for IA2A (tyrosine phosphatase antibodies), GADA (glutamic acid decarboxylase‐65 antibodies) and aTPO by radiobinding assays. The prevalence rates were: GADA 70%; IA2A, 44%; ICA, 39%; aTPO, 22%; PCA, 18%; EmA‐IgA, 2%; and AAA, 1%. aTPO status was determined by female gender (β = − 1·15, P = 0·002), age (β = 0·02, P = 0·01) and GADA + (β = 1·06, P = 0·02), but not by HLA‐DQ type or IA2A status. Dysthyroidism (P < 0·0001) was more frequent in aTPO + subjects. PCA status was determined by age (β = 0·03, P = 0·002). We also observed an association between PCA + and GADA + (OR = 1·9, P = 0·049), aTPO + (OR = 1·9, P = 0·04) and HLA DQA1*0501‐DQB1*0301 status (OR = 2·4, P = 0·045). Iron deficiency anaemia (OR = 3·0, P = 0·003) and pernicious anaemia (OR = 40, P < 0·0001) were more frequent in PCA + subjects. EmA‐IgA + was linked to HLA DQA1*0501‐DQB1*0201 + (OR = 7·5, P = 0·039), and coeliac disease was found in three patients. No patient had Addisons disease. In conclusion, GADA but not IA2A indicate the presence of thyrogastric autoimmunity in type 1 diabetes. aTPO have a female preponderance, PCA are weakly associated with HLA DQA1*0501‐DQB1*0301 and EmA‐IgA + with HLA DQA1*0501‐DQB1*0201.

Seasonality in clinical onset of Type 1 diabetes in Belgian patients above the age of 10 is restricted to HLA-DQ2/DQ8-negative males, which explains the male to female excess in incidence

Aims/hypothesisType 1 diabetes arises from an interplay between environmental and genetic factors. The reported seasonality at diagnosis supports the hypothesis that currently unknown external triggers play a role in the onset of the disease. We investigated whether a seasonal pattern is observed at diagnosis in Belgian Type 1 diabetic patients, and if so whether seasonality varies according to age, sex and genetic risk, all known to affect the incidence of Type 1 diabetes.MethodsThe seasonal pattern at clinical diagnosis was assessed in 2176 islet antibody-positive diabetic patients aged 0 to 39 years diagnosed between 1989 and 2000. Additional stratification was performed for age, sex and HLA-DQ genotype.ResultsOverall, a significant seasonal pattern at clinical diagnosis of diabetes was observed (p<0.001). More subjects were diagnosed in the period of November to February (n=829) than during the period of June to September (n=619) characterised by higher averages of maximal daily temperature and daily hours of sunshine. However, the seasonal pattern was restricted to patients diagnosed above the age of 10 (0–9 years: p=0.398; 10–19 years: p<0.001; 20–29 years: p=0.003; 30–39 years: p=0.015). Since older age at diagnosis is associated with a male to female excess and a lower prevalence of the genetic accelerator HLA-DQ2/DQ8, we further stratified the patients aged 10 to 39 years (n=1675) according to HLA-DQ genotype and sex, and we found that the seasonal pattern was largely restricted to male subjects lacking DQ2/DQ8 (n=748; p<0.001 vs all others: n=927; p=0.031).Conclusions/interpretationIn a subgroup of male patients diagnosed over the age of 10, the later stages of the subclinical disease process may be more driven by sex- and season-dependent external factors than in younger, female and genetically more susceptible subjects. These factors may explain the male to female excess in diabetes diagnosed in early adulthood.

Gastric parietal cell antibodies are associated with glutamic acid decarboxylase-65 antibodies and the HLA DQA1*0501-DQB1*0301 haplotype in Type 1 diabetes mellitus

SUMMARY

Helicobacter pylori, parietal cell antibodies and autoimmune gastropathy in type 1 diabetes mellitus

Fifteen to 20% of type 1 diabetic patients exhibit parietal cell antibodies (PCA), which are associated with autoimmune gastritis, hypochlorhydria, iron deficiency and pernicious anaemia.

Screening for insulinoma antigen 2 and zinc transporter 8 autoantibodies: a cost‐effective and age‐independent strategy to identify rapid progressors to clinical onset among relatives of type 1 diabetic patients

In first‐degree relatives of type 1 diabetic patients, we investigated whether diabetes risk assessment solely based on insulinoma antigen 2 (IA‐2) and zinc transporter 8 (ZnT8) antibody status (IA‐2A, respectively, ZnT8A) is as effective as screening for three or four autoantibodies [antibodies against insulin (IAA), glutamate decarboxylase 65 kDa (GAD) glutamate decarboxylase autoantibodies (GADA) and IA‐2A with or without ZnT8A] in identifying children, adolescents and adults who progress rapidly to diabetes (within 5 years). Antibodies were determined by radiobinding assays during follow‐up of 6444 siblings and offspring aged 0–39 years at inclusion and recruited consecutively by the Belgian Diabetes Registry. We identified 394 persistently IAA+, GADA+, IA‐2A+ and/or ZnT8A+ relatives (6·1%). After a median follow‐up time of 52 months, 132 relatives developed type 1 diabetes. In each age category tested (0–9, 10–19 and 20–39 years) progression to diabetes was significantly quicker in the presence of IA‐2A and/or ZnT8A than in their joint absence (P < 0·001). Progression rate was age‐independent in IA‐2A+ and/or ZnT8A+ relatives but decreased with age if only GADA and/or IAA were present (P = 0·008). In the age group mainly considered for immune interventions until now (10–39 years), screening for IA‐2A and ZnT8A alone identified 78% of the rapid progressors (versus 75% if positive for ≥ 2 antibodies among IAA, GADA, IA‐2A and ZnT8A or versus 62% without testing for ZnT8A). Screening for IA‐2A and ZnT8A alone allows identification of the majority of rapidly progressing prediabetic siblings and offspring regardless of age and is more cost‐effective to select participants for intervention trials than conventional screening.

Insulin treatment in IA-2A-positive relatives of type 1 diabetic patients

AIMS We examined whether parenteral regular insulin can prevent diabetes in IA-2 antibody-positive (IA-2A+) relatives of type 1 diabetic patients, using a trial protocol that differed substantially from that of the Diabetes Prevention Trial-1. METHODS Twenty-five IA-2A+ relatives received regular human insulin twice a day for 36 months, during which time they were followed (median [interquartile range; IQR]: 47 [19-66] months) for glucose tolerance, HbA(1c) and islet autoantibodies, together with 25 IA-2A+ relatives (observation/control group) who fulfilled the same inclusion criteria, but were observed for 52 [27-67] months (P=0.58). RESULTS Twelve (48%) insulin-treated relatives and 15 (60%) relatives in the control group developed diabetes. There was no difference in diabetes-free survival between the two groups (P=0.97). Five-year progression (95% confidence interval) was 44% (25-69) in the insulin-treated group and 49% (29-70) in the observation group. At inclusion, progressors tended to have a higher pro-insulin/C-peptide ratio than non-progressors when measured 2 hours after a standardized glucose load (median [IQR]: 2.7% [1.8-4.3] vs. 1.6% [1.1-2.1]; P=0.01). No major hypoglycaemic episodes or significant increases in body mass index or diabetes autoantibodies were observed. CONCLUSION Prophylactic injections of regular human insulin were well tolerated, but failed to prevent type 1 diabetes onset in IA-2A+ relatives.

The age at diagnosis of type 1 diabetes continues to decrease in Belgian boys but not in girls: a 15-year survey

The age at clinical onset of type 1 diabetes is decreasing. Preliminary Belgian data suggested that this anticipation occurred preferentially in boys. We investigated whether this gender‐specific anticipation could be confirmed over a 15‐year observation period.

Screening for type 2 diabetes mellitus in overweight and obese subjects made easy by the FINDRISC score.

AIM To evaluate the use of the FINDRISC score in an overweight and obese population to predict glucose status. METHODS In 651 overweight/obese subjects (M/F: 193/458, age 43±13 y, BMI 38.2±6.1kg/m(2)) glucose status was tested using OGTT and HbA1c. Furthermore, the FINDRISC questionnaire and CT visceral fat (VAT) and subcutaneous fat (SAT) were examined. RESULTS Exactly 50.4% were found to have prediabetes and 11.1% were newly diagnosed with type 2 diabetes (T2DM) (M/F=22.2/8.8%). Subjects without T2DM had a FINDRISC score of 11±3, those with pre-DM 13±4, and subjects with de novo T2DM 15±5. The aROC of the FINDRISC for detecting T2DM was 0.76 (95% CI 0.72-0.82), with 13 as cutoff point. The FINDRISC score correlated with VAT (r=0.34, p<0.001) and VAT/SAT ratio (r=0.39, p<0.001). The aROC of the FINDRISC to detect excess VAT was 0.79 (95%CI 0.72-0.84). CONCLUSIONS In a large group of overweight and obese subjects, 50.4% were found to have pre-DM and 11.1% were newly diagnosed with T2DM. The FINDRISC score increased with worsening of glucose tolerance status and proved to be an independent predictor of T2DM status, as did HOMA-B, HOMA-S and VAT. The FINDRISC can also function as a good tool to predict visceral obesity.

Not performing an OGTT results in significant underdiagnosis of (pre)diabetes in a high risk adult Caucasian population

Objective:Type 2 diabetes (T2DM) is known to be underdiagnosed. Tests for diagnosis include fasting plasma glucose (FPG), oral glucose tolerance test (OGTT) and HbA1c. HbA1c can be tested in non-fasting conditions. Therefore, general practitioners almost no longer execute OGTT’s. We evaluated the performance of OGTT versus HbA1c in a population consisting of overweight and obese subjects, which can be considered a ‘high risk’ population.Research design and methods:A total of, 1241 overweight and obese subjects without a history of diabetes (male/female: 375/866, age 44±13 years, body mass index 38.0±6.1 kg m−2) were tested for glucose tolerance status using FPG, OGTT and HbA1c.Results:Exactly, 46.8% were found to have prediabetes and 11.9% were newly diagnosed with T2DM (male/female=18.9/8.9%) using ADA criteria. Testing only HbA1c would have resulted in 78 subjects being diagnosed with T2DM, but 47.3% of newly diagnosed patients would have been missed if OGTT would not have been done. Exactly 581 subjects were diagnosed with prediabetes, 1.4% subjects had impaired fasting glucose (IFG) 30.5% had impaired glucose tolerance (IGT), 5.1% subjects had a combined IFG+IGT, and 9.8% had an isolated elevated HbA1c (5.7–6.4%). Of the 581 subjects with prediabetes, 257 had an HbA1c <5.7%. Therefore, 44.2% subjects would have been missed when OGTT would not have been done.Conclusion:In a population with only overweight and obese adult subjects, 46.8% were diagnosed with prediabetes and 11.9% were newly diagnosed with diabetes. Exactly, 5.6 and 20.7% of total population met the diagnostic criteria of the OGTT for diabetes and prediabetes, respectively, but did not meet the diagnostic criteria of the HbA1c. These data suggest that not performing an OGTT results in significant underdiagnose of T2DM in an overweight and obese adult population.

Bariatrische chirurgie ter behandeling van type 2 diabetes: wat is de huidige wetenschappelijk onderbouwde stand van zaken?

Kritische bespreking van de sterke punten en de tekortkomingen van recente vooruitgang die met bariatrische chirurgie geboekt is bij patiënten met type 2 diabetes (T2DM), waarbij de nadruk ligt op werkzaamheidsaspecten (remissie van diabetes en cardiovasculaire comorbiditeiten). Ondanks het zich steeds verder uitbreidende farmacotherapeutisch arsenaal ter bestrijding van problemen, bereikt slechts 10% van de T2DM-patiënten het samengestelde doel van HbA1c, bloeddruk en lipiden. Bariatrische chirurgie is opgekomen als oplossing voor deze bij morbide obesitas behorende problemen. Of deze zelfde voordelen zich ook naar T2DM laten vertalen, blijft een onderwerp van discussie, zeker waar het veiligheid, duurzaamheid van het diabetesherstel en uitkomsten op de lange termijn betreft. Gebleken is dat bariatrische chirurgie bij T2DM-patiënten met een BMI van ten minste 35 kg/m2 bij 56% resulteert in overmatig verlies van lichaamsgewicht, bij 63% in herstel van hypertensie, bij meer dan 70% in verbetering van dislipidemie en bij 57-90% in remissie van diabetes, afhankelijk van het type operatie en de definitie van verdwijnen van diabetes. Deze indrukwekkende resultaten, en het feit dat diabetes herstel zich vaak al voordoet voordat sprake is van belangrijk gewichtsverlies, hebben bariatrische chirurgen ertoe aangezet chirurgische procedures te beschouwen als waardevolle benadering voor diabetesregulering en diabetesremissie bij patiënten met een BMI tussen 30 en 35 kg/m2. Bariatrische chirurgie is aan een opmars bezig als valide T2DM-behandeloptie die glycemie en cardiovasculaire risicofactoren verbetert. In komende studies moet echter een overeengekomen definitie van ‘verdwijnen van diabetes’ worden gehanteerd en dient de werkzaamheid op de lange termijn te worden bewezen. Het probleem voor dit moment is hoe bariatrische chirurgie op een verantwoordelijke wijze kan worden aangeboden.