Increasing incidence of type 1 diabetes in population from Santiago of Chile: trends in a period of 18 years (1986-2003)

Budget impact analysis of the freestyle libre flash continuous glucose monitoring system® in patients with diabetes mellitus type 1 in Chile

OBJECTIVE

To estimate the budget impact of covering the FreeStyle Libre Flash Continuous Glucose Monitoring System (FSL) for type 1 Diabetes Mellitus patients (T1DM), compared to self-monitoring of blood glucose (SMBG), from the perspective of public and private third-party payers in Chile.

METHODS

A budget impact model was developed to estimate the cost difference between SMBG and FSL over five years. Two FSL coverage schemes were assessed. Input parameters were retrieved from the literature review and complemented by expert opinion. Healthcare costs were estimated by a micro-costing approach and reported in USD.

RESULTS

For a public sector third-party payer, incorporating FSL implied a cost increase up to USD 0.013 per member per month (PMPM) for the fifth year under the broad coverage scheme and a net saving of 0.0001 PMPM (all years) under the restricted coverage scheme. From a private sector third-party payer, incorporating FSL implied savings up to USD 0.028 PMPM (fifth year) for the broad coverage scheme and up to USD 0.012 PMPM (fifth year) for the restricted scheme.

CONCLUSION

Incorporating the FSL for T1DM patients was associated with a marginal incremental cost for the public sector third-party payer and cost savings in Chile's private healthcare sector.

Body fat composition and miR-378 expression profiling in patients with type 1 diabetes

PURPOSE

Type 1 diabetes (T1D) is an autoimmune disease that involves genetic, epigenetic, and environmental factors. Change in body composition is a potential mechanism for explaining the increased incidence of T1D. Micro RNA-378 (miRNA-378) is a positive regulator of adipogenesis that has yet to be studied in such patients. This study aims to evaluate the miRNA-378 expression profile in peripheral mononuclear cells of T1D patients and controls and to determine its possible association with levels of body fat, interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α).

METHODS

Twenty-four T1D subjects and 20 controls under 18 years of age without autoimmune diseases were studied. miRNA-378 expression profile was determined by TaqMan probes. Body composition was determined by multifrequency bioimpedance. IL-6 and TNF-α serum levels were determined by LUMINEX. AntiGAD65, anti-IA2, and anti-ZnT8 antibodies were quantified in serum by enzyme immunoassays. Statistical significance was considered P<0.05.

RESULTS

Similar body mass index and body fat (kg) were observed between the T1D and control subjects (P=0.55 and P=0.69, respectively). The miRNA-378 expression profile was significantly higher in T1D patients compared with the controls (P<0.05). Lower miRNA-378 expression in prepubertal controls was observed compared to pubertal controls, prepubertal T1D, and pubertal T1D (P<0.05). AntiGAD65, AntilA2, and AntiZnT8 were positively correlated with miRNA-378 (P=0.002, P=0.053, and P=0.007). No statistically significant correlation was observed between miRNA-378 expression and IL-6, TNF-α, or body fat.

CONCLUSION

Elevated miRNA-378 expression in T1D patients compared with controls is linked to pubertal stage but is not associated with proinflammatory status or body composition.

Prevalence and incidence of type 1 diabetes in the world: a systematic review and meta-analysis

Background: Diabetes is referred to a group of diseases characterized by high glucose levels in blood. It is caused by a deficiency in the production or function of insulin or both, which can occur because of different reasons, resulting in protein and lipid metabolic disorders. The aim of this study was to systematically review the prevalence and incidence of type 1 diabetes in the world. Methods: A systematic search of resources was conducted to investigate the prevalence and incidence of type 1 diabetes in the world. The databases of Medline (via PubMed and Ovid),ProQuest, Scopus, and Web of Science from January 1980 to September 2019 were searched to locate English articles. The located articles were screened in multiple levels of title, abstract,and full-text and final studies that met the inclusion criteria were retrieved and included in the study. Results: From 1202 located articles, 193 studies were included in this systematic review. The results of meta-analysis showed that the incidence of type 1 diabetes was 15 per 100,000 people and the prevalence was 9.5% (95% CI: 0.07 to 0.12) in the world, which was statistically significant. Conclusion: According to the results, the incidence and prevalence of type 1 diabetes are increasing in the world. As a result, insulin will be difficult to access and afford, especially in underdeveloped and developing countries.

Incidence and trend of type 1 diabetes and the underlying environmental determinants

A wealth of epidemiological studies concerning the distribution of type 1 diabetes (T1D) around the world have pointed to the appreciable variation in the incidence of T1D among disparate age groups, ethnicities, and geographical locations. On the whole, the incidence of childhood T1D has been on the rise, and a plausible inverse relationship between the initial incidence rate and the following annual increase in incidence has been raised. Countries that used to exhibit lower incidences tend to have steep annual increase whereas those with already-established high incidences are more likely to show a modest increase or even stabilization in T1D incidence. Environmental agents considered responsible for the current evolving pattern of T1D incidence will be detailed, mainly including the increasing prevalence of childhood obesity, viral infections in a chronic manner, maternal-child interaction such as breastfeeding, and latitude-ultraviolet B-vitamin D pathway. Certain rationale has been put forward in an attempt to explain the potential association between environmental agents and development of T1D. For instance, accelerator hypothesis regards insulin resistance as the promoter of earlier disease onset in obese children whereas the negative correlation of microbial infections in background populations with incidence of T1D represents the basic component of the hygiene hypothesis. Further investigations are still warranted to verify these theories across multiple ethnic groups and to identify additional contributors to the variation in T1D incidence.

HLA-B*39:06 Efficiently Mediates Type 1 Diabetes in a Mouse Model Incorporating Reduced Thymic Insulin Expression

Type 1 diabetes (T1D) is characterized by T cell-mediated destruction of the insulin-producing β cells of the pancreatic islets. Among the loci associated with T1D risk, those most predisposing are found in the MHC region. HLA-B*39:06 is the most predisposing class I MHC allele and is associated with an early age of onset. To establish an NOD mouse model for the study of HLA-B*39:06, we expressed it in the absence of murine class I MHC. HLA-B*39:06 was able to mediate the development of CD8 T cells, support lymphocytic infiltration of the islets, and confer T1D susceptibility. Because reduced thymic insulin expression is associated with impaired immunological tolerance to insulin and increased T1D risk in patients, we incorporated this in our model as well, finding that HLA-B*39:06-transgenic NOD mice with reduced thymic insulin expression have an earlier age of disease onset and a higher overall prevalence as compared with littermates with typical thymic insulin expression. This was despite virtually indistinguishable blood insulin levels, T cell subset percentages, and TCR Vβ family usage, confirming that reduced thymic insulin expression does not impact T cell development on a global scale. Rather, it will facilitate the thymic escape of insulin-reactive HLA-B*39:06-restricted T cells, which participate in β cell destruction. We also found that in mice expressing either HLA-B*39:06 or HLA-A*02:01 in the absence of murine class I MHC, HLA transgene identity alters TCR Vβ usage by CD8 T cells, demonstrating that some TCR Vβ families have a preference for particular class I MHC alleles.

The Elevated Rate of Cesarean Section and Its Contribution to Non-Communicable Chronic Diseases in Latin America: The Growing Involvement of the Microbiota

The current recommendation of the World Health Organization (WHO) regarding cesarean section (C-section) is that this clinical practice should be carried out only under specific conditions, when the health or life of the mother/newborn dyad is threatened, and that its use should not exceed 10-15% of the total deliveries. However, over the last few decades, the frequency of C-section delivery in medium- and high-income countries has rapidly increased worldwide. This review describes the evolution of this procedure in Latin American countries, showing that today more than half of newborns in the region are delivered by C-section. Given that C-section delivery is more expensive than vaginal delivery, its use has increased more rapidly in the private than the public sector; nevertheless, the prevalence of C-section deliveries in the public sector is higher than the WHO's recommendations and continues to increase, representing a growing challenge for Latin America. Although the medium- and long-term consequences of C-section delivery, as opposed to vaginal delivery, on the infant health are unclear, epidemiological studies suggest that it is associated with higher risk of developing asthma, food allergy, type 1 diabetes, and obesity during infancy. These findings are important, as the incidence of these diseases in the Latin American pediatric population is also increasing, particularly obesity. Although the link between these diseases and delivery mode remains controversial, recent studies indicate that the establishment of the gut microbiota is delayed in infants born by C-section during the postnatal period, i.e., during a critical developmental window for the maturation of the newborn's immune system. This delay may favor the subsequent development of inflammatory and metabolic disorders during infancy. Accordingly, from a public health perspective, it is important to slow down and eventually reverse the pattern of increased C-section use in the affected populations.

[Expression of miR-22 and miR-150 in type 1 diabetes mellitus: Possible relationship with autoimmunity and clinical characteristics]

BACKGROUND AND OBJECTIVE

Type 1 diabetes (T1D) is an autoimmune disease of complex aetiology. Several microRNAs (miR) have been linked to the pathogenesis of autoimmune diseases. To analyze the possible association of miR-22 and miR-150 with autoimmunity and clinical severity of T1D.

PATIENTS AND METHODS

The study was performed in peripheral blood mononuclear cells of 20 patients with T1D and 20 control subjects. The expression of miR-22 and miR-150 was performed in peripheral blood mononuclear cells using TaqMan probes to different glucose concentrations (baseline, 11mm, 25mm).

RESULTS

Our results suggest that the expression of miR-22 is increased in T1D patients compared to the controls. This effect was observed in baseline glucose conditions and decreased in 11 and 25mM of glucose. The expression of miR-150 was lower in T1D patients versus the controls. There was no correlation between the autoimmune profile and the two studied miRNAs. miR-22 (baseline condition) and miR-150 (11mM condition) or the ketoacidosis component.

CONCLUSION

miR-22 and 150 were not associated with the autoimmune component present in T1D patients.

High birth weights but not excessive weight gain prior to manifestation are related to earlier onset of diabetes in childhood: 'accelerator hypothesis' revisited

AIMS/HYPOTHESIS

Aim of this study was to test Wilkin's 'accelerator hypothesis': whether excessive weight gain accelerates the onset of type 1 diabetes.

SUBJECTS AND METHODS

Anthropometric birth data of 1117 children who developed diabetes between 1988 and April 2013 were compared with those of a sex, age, and gestational age matched, contemporary regional control group (n = 54 344). Cases were divided into three manifestation groups (G1:0-4.9 yr, G2:5-9.9 yr, and G3: 10-20 yr). Furthermore, growth data of 540 children with diabetes were compared with controls (n = 134 249) in pre-, peri-, and post-onset intervals (interval: 1-6). Also, correlation of age at onset and body mass index (BMI) standard deviation score (SDS) at this point of time were examined.

RESULTS

Cases had significantly higher SDSs for birth weight when compared with controls (boys: p = 0.007, girls: p = 0.002). Children with early manifestation had the highest mean of birth weight SDS (G1>G2>G3), (p = 0.22, adjusted r(2) = 0.001). BMI SDS trend curves of cases are slightly higher compared with those of the healthy controls. This was only significant in years after diagnosis (interval 6, p < 0.000). Cases did not show excessive weight gain in any of the examined intervals before the onset of diagnosis (interval 1-3). One year after diagnosis, we found an inverse correlation between age at diagnosis and BMI SDS at diabetes manifestation. The youngest children at diagnosis (G1) had the lowest BMI SDS at manifestation and vice versa (G1<G2<G3, p = 0.06).

CONCLUSIONS

Our data do not support the 'accelerator hypothesis'. There was no sign of excessive weight gain before manifestation. Discrepant results from other studies could be due to non-age-adjusted controls.

Diabetes in South and Central America: an update

The estimated population of the South and Central America (SACA) Region is 467.6 million and 64% is in the age range of 20-79 years but the population pyramid and age distribution are changing. The average prevalence of diabetes in the Region is 8.0% and is expected to reach 9.8% by the year 2035. Prevalence is much lower in rural settings than in urban and the differences attributed to lifestyle changes may be a target for intervention. The indigenous population is a particularly vulnerable group needing special attention. On average, 24% of the adult cases with diabetes are undiagnosed but in some countries this is still as high as 50%. Health expenditure due to diabetes in the Region is around 9% of the global total. Inadequate glycemic control, defined as HbA1c >7%, is a strong predictor of chronic complications which increase resource use in the Region and less than half of the patients enrolled in diabetes care programmes are at target. Fifty percent or more of the adult population is overweight/obese and around one third of the adult population has metabolic syndrome using regional cutoffs for waist circumference. The number of people with IGT is almost equal to those with diabetes presenting an additional challenge for prevention. Children with type 1 diabetes represent only 0.2% of the total population with diabetes but the incidence may be increasing. In many places they have limited access to insulin, and even when available, it is not used appropriately. The available epidemiological data provide the background to act in developing national diabetes programmes which integrate diabetes care with cardiovascular prevention and promote diabetes prevention as well.

Variation between countries in the frequency of diabetic ketoacidosis at first presentation of type 1 diabetes in children: a systematic review

AIMS/HYPOTHESIS

Type 1 diabetes is the most frequent endocrine disease in children, with 65,000 children diagnosed worldwide every year. Up to 80% of these children present with diabetic ketoacidosis (DKA), which is associated with both short-term risks and long-term consequences. This study aimed to characterise the worldwide variation in presentation of type 1 diabetes to inform future interventions to reduce this excess morbidity and mortality.

METHODS

This was a systematic review of studies indexed on PubMed, EMBASE, Web of Science, Scopus or CINAHL before March 2011 that included unselected groups of children presenting with new-onset type 1 diabetes, reported the proportion presenting with DKA and used a definition of DKA based on measurement of pH or bicarbonate.

RESULTS

Sixty-five studies of cohorts comprising over 29,000 children in 31 countries were included. The frequency of DKA at diagnosis ranged from 12.8% to 80%, with highest frequencies in the United Arab Emirates, Saudi Arabia and Romania, and the lowest in Sweden, the Slovak Republic and Canada. Multivariable modelling showed the frequency of DKA was inversely associated with gross domestic product, latitude and background incidence of type 1 diabetes.

CONCLUSIONS/INTERPRETATION

This is the first description of the variation in frequency of DKA at presentation of type 1 diabetes in children across countries. It demonstrates large variations that may, at least in part, be explained by different levels of disease awareness and healthcare provision and suggests ways to decrease the excess morbidity and mortality associated with DKA at diagnosis.

Air pollution and hospitalization for acute complications of diabetes in Chile

Exposure to air pollution has been shown to cause insulin resistance in mice. To determine the relevance to humans, we tested the association between daily air pollution concentrations and daily hospitalization for acute serious complications of diabetes, coma and ketoacidosis, in Santiago between 2001 and 2008, using generalized linear models with natural splines to control for long term trends. For an interquartile range (IQR) increase in air pollutant, the relative risks (95% CI) of hospitalization for diabetes were: 1.15 (1.10, 1.20) for carbon monoxide (IQR=1.00); 1.07 (0.98, 1.16) for ozone (IQR=63.50); 1.14 (1.06, 1.22) for sulfur dioxide (IQR=5.88); 1.12(1.05, 1.20) for nitrogen dioxide (IQR=27.94); 1.11 (1.07, 1.15) for particulate matter≤10 μm diameter(IQR=34.00); and 1.11 (1.06, 1.16) for fine particulate matter ≤2.5 μm diameter (IQR=18.50). Results were similar when stratified by age, sex and season. Air pollution appears to increase the risk of acute complications of diabetes requiring hospitalization, suggesting that improvements in air quality may reduce morbidity from diabetes.

The changing epidemiology of type 1 diabetes: why is it going through the roof?

The incidence of type 1 diabetes is increasing and this may double the burden of disease in our youngest by 2020. The recent increase in incidence is mostly happening in the very young and those with moderate genetic susceptibility. Many environmental factors have been implicated, but no major determinants have been clearly identified, and the mechanisms of involvement remain elusive. This review summarizes current research efforts directed at understanding the possible reasons for this increase, including the role of viruses, gut microbiota, early life feeding patterns, perinatal factors and childhood growth patterns. It also provides a road map for future research directions.

Clustering of cases of type 1 diabetes in high socioeconomic communes in Santiago de Chile: spatio-temporal and geographical analysis

The objective of this study was to describe spatial and space-time patterns of type 1 diabetes in children less than 15 years old, diagnosed between 2000 and 2005 with residence in the Metropolitan Region of Chile. Knox and Mantel tests were used to detect space-time interaction between cases. An ecological Bayesian model adjusted by socioeconomic factor and year was proposed to estimate the incidence by communes. Initially, there was no space-time interaction between cases, but there is evidence of clustering effect in urban areas of the region. The incidence rate for the overall study period was estimated by 6.18/100,000 (95% CI: 5.69-6.70), with a significant annual trend of 8.2% (P < 0.01). The geographical incidence could be explained by the human development index, as a socioeconomic factor. These results suggest that children living in communes with higher socioeconomic levels may be at higher risk of developing type 1 diabetes. Our findings support the hypothesis of an aetiological role of environmental factors in the onset of type 1 diabetes.

High concentrations of anti-caspase-8 antibodies in Chilean patients with type 1 diabetes

INTRODUCTION

Deregulation of apoptosis across the Fas-FasL pathway is an increasingly relevant phenomenon in the pathogenic mechanisms associated with autoimmune diseases. Caspase-8 initiates the activation of the apoptotic process and interacts directly with Fas in the membrane of the T lymphocyte.

OBJECTIVES

To standardize an Elisa essay to measure the concentration of anti-caspase-8 antibodies in plasma of Type 1 Diabetes (T1D) patients and analyze their possible distribution and association with characteristics of the disease.

METHODS AND SUBJECTS

124 patients newly diagnosed with T1D and 132 controls: children and youngsters. ELISA test was standardized to detect anti-caspase-8 antibodies in plasma. It correlated the concentration of this antibody with classical markers of autoimmunity as anti-IA-2 and anti-GAD65, and the clinical characteristics at onset of diabetes mellitus. The statistical analysis was performed using logistic regression.

RESULTS

Patients with T1D showed a higher concentration of anti-caspase-8 antibodies regarding the controls (87.5 ng/ml versus 24.3 ng/ml, p < 0.0001, values expressed as median). The proportion of patients with T1D and high concentrations of anti-caspase-8 (percentile 50-75) was significantly different from the control group (p < 0.0001). Anti-caspase-8 showed a strong association with positive anti-GAD65 (OR = 3.48, p < 0.035) and ketoacidosis (OR = 10.74, p < 0.0001) events, with glycemia and age at diagnosis as contributing variables.

CONCLUSION

This is the first report in the literature of levels of anti-caspase-8 antibodies in T1D through ELISA. The high concentration in patients with T1D, and its strong correlation with anti-GAD65 auto-antibodies, suggests a potential role of anti-caspase-8 auto-antibodies as surrogate marker autoimmunity in T1D patients.

Associations of the CTLA-4 polymorphisms with type 1 diabetes in a Chilean population: case-parent design

CTLA-4 plays a key role in T cells regulation. We analysed the CTLA-4 +49A/G and -318C/T polymorphisms in 178 cases of type 1 diabetes and their parents (534 individuals) from Santiago, Chile. A significant overall association with T1D (p=0.028) was observed, possibly due to an overtransmission of the G-T haplotype.

Interactions between programmed death 1 (PD-1) and cytotoxic T lymphocyte antigen 4 (CTLA-4) gene polymorphisms in type 1 diabetes

AIM

To explore the contribution of the PD-1 gene polymorphisms involved in T1D as well as the relationship between the PD-1/CTLA-4 genes and soluble CTLA-4 concentrations.

PATIENTS AND METHODS

261 incident cases of T1D and 280 healthy children less 15 years old were included in this study. Haplotypes for polymorphisms of the PD-1 and CTLA-4 genes were determined by PCR and RFLP methods. Screening for soluble CTLA-4 was done using an ELISA assay. Statistical analysis was performed using the online SHESIS package.

RESULTS

Our results show that sCTLA-4 levels were higher in T1D than in controls (2.99+/-1.7 ng/ml versus 1.43+/-0.31 ng/ml, p<0.001). The allele dosage of CTLA-4 on PD-1 haplotypes, showing a significant modified effect of G carriers over AA genotype on the sCTLA-4 concentrations (5.48+/-2.09 ng/ml versus 3.27+/-1.30 ng/ml, p<0.03 in T-C haplotype) and (1.92+/-0.79 ng/ml versus 3.41+/-1.10 ng/ml, p<0.02 in C-T haplotype).

CONCLUSION

Consistent with the higher serum sCTLA-4 levels observed in other autoimmune diseases, our results suggest that sCTLA-4 is elevated in T1D. Our data suggest a possible gene dosage effect of "G"CTLA-4 carriers on sCTLA-4 over the possible protective or susceptible effect conferred by PD-1 haplotypes.

Increasing incidence of type 1 diabetes in children aged 0-14 years in Harbin, China (1990-2000)

AIMS

(1) To determine the incidence of type 1 diabetes mellitus in children aged<15 years in Harbin, China and (2) to examine the trend in incidence over the period from 1990 to 2000.

METHODS

Newly diagnosed cases of type 1 diabetes from 1990 to 2000 were identified among 1,286,154 Chinese children aged 0-14 years in Harbin. The primary source of case ascertainment was from hospital records and the secondary source from the health records of school clinics.

RESULTS

One hundred and three cases were identified during 1990 and 2000. The annual incidence rate was 0.73 per 100,000 (95% CI: 0.59-0.88 per 100,000). No significant difference between males and females in the incidence of type 1 diabetes was observed. The incidence was significantly associated with age. With those aged<5 years as reference, the rate ratios were 2.06 and 4.1 for those aged 5-9 and 10-14 years, respectively. The incidence was higher in urban than in suburban regions, particularly among those aged 10-14 years. No significant seasonality was observed. There was a significant increasing trend in the incidence of type 1 diabetes during the period of 1990 and 2000, with an annual increase of 7.4% (95% CI: 1.6-13.5%).

CONCLUSIONS

There is a significantly increasing trend in the incidence of type 1 diabetes among children in Harbin. Increased number of cases has important implications for diabetes care providers. Understanding the etiology of this rise is critical for developing preventive measures to halt the trend.

Incidence of childhood type I and non-type 1 diabetes mellitus in a diverse population: the Chicago Childhood Diabetes Registry, 1994 to 2003

BACKGROUND

Reports of increasing risk for type 1 (T1) and type 2 diabetes mellitus in youth are emerging, but information on socioeconomically diverse populations is limited.

METHOD

The Chicago Childhood Diabetes Registry is a city-wide study of patients 0-17 years old at onset. Incidence data came from medical records and interviews; census data provided denominators; analyses used Poisson regression. Non-type 1 (nT1) patients had a type 2-like clinical course or related indicators.

RESULTS

There were 1,366 incident cases: 719 in non-Hispanic Black (NHB), 379 in Hispanic, 229 in non-Hispanic White (NHW), and 39 in children of other ethnicities. Average annual incidence was 16.0 (95% CI: 14.6, 17.6)/10(5) for boys, 20.1 (18.3, 22.1)/10(5) for girls, and 18.1 (16.9, 19.3)/10(5) overall. Risk was 21.6 (19.6, 23.8)/10(5) for NHB, 14.6 (13.0, 16.4)/10(5) for Hispanic, and 18.1 (15.9, 20.6)/10(5) for NHW. Children aged 10-14 years experienced the highest incidence, irrespective of ethnicity. T1 was predominant in all ethnic groups, except NHB, where the rates of T1 and nT1 were similar. Over ten years there was a marked increase in all childhood diabetes in Chicago, averaging 2.73% (95% CI: 0.49, 5.02) per annum, adjusted for age. This increase was confined to nT1, with an average annual percent change of +6.23% (2.28, 10.34), while T1 incidence remained stable.

CONCLUSIONS

Incidence of childhood diabetes increased between 1994-2003, driven primarily by nT1, suggesting a role for behavioral and/or environmental determinants of insulin resistance. These estimates are likely to be conservative, if nT1 cases were more apt to be missed.

VDR polymorphisms influence the immune response in type 1 diabetic children from Santiago, Chile

OBJECTIVE

To evaluate the influence of ApaI, BsmI and TaqI polymorphisms of the VDR gene and HLA-DQB1* alleles in type 1 diabetic children and to assess their possible relationship with circulating levels of 25-hydroxyvitamin D(3), auto-antibodies, and INFgamma/TGFbeta1 cytokines levels in Chilean cases and controls.

METHODS

DNA and serum samples from 216 newly diagnosed type 1 diabetic and 203 unrelated control children were evaluated for IA-2 and GAD(65) auto-antibodies, 25-hydroxyvitamin D(3) levels, HLA-DQB1* alleles, and VDR gene polymorphisms.

RESULTS

The frequency of the b allele and the bb genotype in type 1 diabetic patients was significantly lower compared with the control group (0.635 versus 0.749, p<0.01 and 0.370 versus 0.567, p<0.04). 25-Hydroxyvitamin D(3) levels showed no differences between type 1 diabetic and healthy children. In cases, 25-hydroxyvitamin D(3) levels were not associated with a special auto-antibodies profile according to the presence or absence of GAD(65)(+) or IA-2(+). The haplotype combination BAT was higher in cases (0.062 versus 0.019, p<0.0022) and bAT was more frequent in controls (0.266 versus 0.180, p<0.003). In cases, the aaBbTT genotype showed the most significant increase in TGFbeta1 level across the VDR categories. Finally, when considering the HLA class II risk genotype (DQB1*0302) and the VDR genotypes (AabbTT and aabbTT), higher levels of GAD(65), IA-2 and TGFbeta1 were observed among diabetic children.

CONCLUSION

We found an association between a VDR polymorphism (BsmI) and type 1 diabetes. An association was found of AabbTT and aabbTT genotypes and the HLA-DQB1*0302 allele with high levels of GAD(65), IA-2 and TGFbeta1.