Characteristics of rapid vs slow progression to type 1 diabetes in multiple islet autoantibody-positive children

Aims/hypothesis

Islet autoantibody-positive children progress to type 1 diabetes at variable rates. In our study, we asked whether characteristic autoantibody and/or gene profiles could be defined for phenotypes showing extreme progression.

Methods

Autoantibodies to insulin (IAA), GAD (GADA), insulinoma-associated antigen-2 (IA-2A) and zinc transporter 8 (ZnT8A) were measured in follow-up sera, and genotyping for type 1 diabetes susceptibility genes (HLA-DR/HLA-DQ, INS variable number of tandem repeats [VNTR] and single nucleotide polymorphisms at PTPN22, PTPN2, ERBB3, IL2, SH2B3, CTLA4, IFIH1, KIAA0350 [also known as CLEC16A], CD25, IL18RAP, IL10, COBL) was performed on the DNA samples of children born to a parent with type 1 diabetes and prospectively followed from birth for up to 22 years.

Results

Of the 1,650 children followed, 23 developed multiple autoantibodies and progressed to diabetes within 3 years (rapid progressors), while 24 children developed multiple autoantibodies and remained non-diabetic for more than 10 years from seroconversion (slow progressors). Rapid and slow progressors were similar with respect to HLA-DR/HLA-DQ genotypes, development of IAA, GADA and ZnT8A, and progression to multiple autoantibodies. In contrast, IA-2A development was considerably delayed in the slow progressors. Furthermore, both groups were effectively distinguished by the combined presence or absence of type 1 diabetes susceptibility alleles of non-HLA genes, most notably IL2, CD25, INS VNTR, IL18RAP, IL10, IFIH1 and PTPN22, and discrimination was improved among children carrying high-risk HLA-DR/HLA-DQ genotypes.

Conclusions/interpretation

Our data suggest that genotypes of non-HLA type 1 diabetes susceptibility genes influence the likelihood or rate of diabetes progression among children with multiple islet autoantibodies.     

Late-onset islet autoimmunity in childhood: the Diabetes Autoimmunity Study in the Young (DAISY)

Aims/hypothesis

We sought to assess the frequency, determinants and prognosis for future diabetes in individuals with islet autoimmunity and whether these factors differ depending on the age of onset of islet autoimmunity.

Methods

A prospective cohort (n = 2547) of children from the general population who had a high-risk HLA genotype and children who had a first-degree relative with type 1 diabetes were followed for up to 21 years. Those with the persistent presence of one or more islet autoantibodies were categorised as early-onset (<8 years of age, n = 143, median 3.3 years) or late-onset (≥8 years of age, n = 64, median 11.1 years), and were followed for a median of 7.4 and 4.7 years, respectively. Progression to diabetes was evaluated by Kaplan–Meier analysis with logrank test. Factors associated with progression to diabetes were analysed using the parametric accelerated failure time model.

Results

Children with late-onset islet autoimmunity were more likely to be Hispanic or African-American than non-Hispanic white (p = 0.004), and less likely to be siblings of individuals with type 1 diabetes (p = 0.04). The frequencies of the HLA-DR3/4 genotype and non-HLA gene variants associated with type 1 diabetes did not differ between the two groups. However, age and HLA-DR3/4 were important predictors of rate of progression to both the presence of additional autoantibodies and type 1 diabetes. Late-onset islet autoimmunity was more likely to present with a single islet autoantibody (p = 0.01) and revert to an antibody-negative state (p = 0.01). Progression to diabetes was significantly slower in children with late-onset islet autoimmunity (p < 0.001).

Conclusions/interpretation

A late onset of islet autoimmunity is more common in African-American and Hispanic individuals. About half of those with late-onset islet autoimmunity progress to show multiple islet autoantibodies and develop diabetes in adolescence or early adulthood. Further investigation of environmental determinants of late-onset autoimmunity may lead to an understanding of and ability to prevent adolescent and adult-onset type 1 diabetes.

     

GAD autoantibody affinity in schoolchildren from the general population

Aims/hypothesis

Subtyping GAD autoantibody (GADA) responses using affinity measurement allows the identification of GADA-positive children with a family history of type 1 diabetes who are at risk of developing diabetes. Here, we asked whether GADA affinity is a useful marker to stratify the risk of type 1 diabetes in GADA-positive schoolchildren from the general population.

Methods

GADA affinity was measured by competitive binding experiments with [¹²⁵I]-labelled and unlabelled human 65 kDa isoform of GAD (GAD65) in sera from 97 GADA-positive children identified in the Karlsburg Type 1 Diabetes Risk Study of a general schoolchild population in north-eastern Germany. GADA epitope specificity was determined using radiobinding assays with [³⁵S]-labelled GAD65/67 kDa isoform of GAD (GAD67) chimeric proteins.

Results

GADA affinity was high, ≥10¹⁰ l/mol, in 33 of 35 multiple islet autoantibody-positive children. In contrast, the affinity ranged widely among 62 single GADA-positive children (median 3.1?×?10⁹ l/mol; range 5.6?×?10⁶ to >4.0?×?10¹¹ l/mol; p?p?=?0.02) and predominantly directed against the C-terminal and/or middle part of the GAD65 protein. At follow-up, the affinity remained relatively constant. Five of the single GADA-positive children developed additional islet autoantibodies and had high-affinity GADA. Twenty-six children progressed to type 1 diabetes; among them, 23 had GADA affinities of ≥10¹⁰ l/mol before disease onset.

Conclusions/interpretation

Schoolchildren from the general population may develop heterogeneous GADA responses, and a high affinity can identify those GADA-positive children who are more likely to progress to type 1 diabetes.     

No association of vitamin D intake or 25-hydroxyvitamin D levels in childhood with risk of islet autoimmunity and type 1 diabetes: the Diabetes Autoimmunity Study in the Young (DAISY)

Aims/hypothesis

The aim of the study was to investigate the association between vitamin D intake and status and the risk of islet autoimmunity (IA) and subsequent type 1 diabetes in children at increased risk of type 1 diabetes.

Methods

The Diabetes Autoimmunity Study in the Young (DAISY) in Denver, CO, USA, has been following children at increased risk of diabetes since 1993. As of February 2011, 198 children developed IA during follow-up of 2,644 DAISY children. Vitamin D intake and plasma 25-hydroxyvitamin D [25(OH)D] were measured longitudinally. Proportional hazards regression analyses of time to IA, or type 1 diabetes in IA-positive children, were conducted, with vitamin D intake and 25(OH)D as time-varying covariates. HRs were calculated for a standard deviation difference in exposure, with adjustment for confounders.

Results

Intake of vitamin D was not associated with the risk of IA (adjusted HR 1.13; 95% CI 0.95, 1.35; p?=?0.18) nor progression to diabetes in IA-positive children (adjusted HR 1.30; 95% CI 0.91, 1.86; p?=?0.15). Moreover, 25(OH)D level was not associated with the risk of IA (adjusted HR 1.12; 95% CI 0.88, 1.43; p?=?0.36), nor progression to diabetes in IA-positive children (adjusted HR 0.91; 95% CI 0.68, 1.22; p?=?0.54). In the 128 children in whom we measured 25(OH)D at 9?months of age, 25(OH)D was not associated with risk of IA (n?=?30 IA-positive children) (adjusted HR 1.02; 95% CI 0.96, 1.07; p?=?0.58).

Conclusions/interpretation

Neither vitamin D intake nor 25(OH)D levels throughout childhood were associated with the risk of IA or progression to type 1 diabetes in our population.     

Thyroid autoimmunity in relation to islet autoantibodies and HLA-DQ genotype in newly diagnosed type 1 diabetes in children and adolescents

Aims/hypothesis

The aim of this work was to investigate, in children newly diagnosed with type 1 diabetes: (1) the prevalence of autoantibodies against thyroid peroxidase (TPOAb) and thyroglobulin (TGAb); and (2) the association between TPOAb, TGAb or both, with either islet autoantibodies or HLA-DQ genes.

Methods

Blood samples from 2,433 children newly diagnosed with type 1 diabetes were analysed for TPOAb and TGAb in addition to autoantibodies against arginine zinc transporter 8 (ZnT8RA), tryptophan zinc transporter 8 (ZnT8WA), glutamine zinc transporter 8 (ZnT8QA), glutamic acid decarboxylase (GADA), insulin (IAA), insulinoma-associated protein-2 (IA-2A), HLA-DQA-B1 genotypes, thyroid-stimulating hormone (TSH) and free thyroxine (T4).

Results

At type 1 diabetes diagnosis, 12% of the children had thyroid autoantibodies (60% were girls; p?<?0.0001). GADA was positively associated with TPOAb (p?<?0.001) and with TGAb (p?<?0.001). In addition, ZnT8A was associated with both TPOAb (p?=?0.039) and TGAb (p?=?0.015). DQB1*05:01 in any genotype was negatively associated with TPOAb (OR 0.55, 95% CI 0.37, 0.83, p value corrected for multiple comparisons (p _c)?=?0.012) and possibly with TGAb (OR 0.55, 95% CI 0.35, 0.87, p _c?=?0.07). Thyroid autoimmunity in children newly diagnosed with type 1 diabetes was rarely (0.45%) associated with onset of clinical thyroid disease based on TSH and free T4.

Conclusions/interpretation

GADA and ZnT8A increased the risk for thyroid autoimmunity at the time of clinical diagnosis of type 1 diabetes, while HLA-DQB1*05:01 reduced the risk. However, the associations between thyroid autoimmunity and HLA-DQ genotype were weak and did not fully explain the co-occurrence of islet and thyroid autoimmunity.     

Effects of calcium–vitamin D co-supplementation on metabolic profiles in vitamin D insufficient people with type 2 diabetes: a randomised controlled clinical trial

Aims/hypothesis

This study was performed to assess the effects of vitamin D and calcium supplementation on the metabolic profiles of vitamin D insufficient persons with type 2 diabetes.

Methods

In a parallel designed randomised placebo-controlled clinical trial, a total of 118 non-smoker individuals with type 2 diabetes and insufficient 25-hydroxyvitamin D, aged >30 years, were recruited from the Isfahan Endocrine and Metabolism Research Centre. Participants were randomly assigned to four groups receiving: (1) 50,000 U/week vitamin D + calcium placebo; (2) 1,000 mg/day calcium + vitamin D placebo; (3) 50,000 U/week vitamin D + 1,000 mg/day calcium; or (4) vitamin D placebo + calcium placebo for 8 weeks. A study technician carried out the random allocations using a random numbers table. All investigators, participants and laboratory technicians were blinded to the random assignments. All participants provided 3 days of dietary records and 3 days of physical activity records throughout the intervention. Blood samples were taken to quantify glycaemic and lipid profiles at study baseline and after 8 weeks of intervention.

Results

30 participants were randomised in each group. During the intervention, one participant from the calcium group and one from the vitamin D group were excluded because of personal problems. Calcium–vitamin D co-supplementation resulted in reduced serum insulin (changes from baseline: ?14.8?±?3.9 pmol/l, p?=?0.01), HbA_1c [?0.70?±?0.19% (?8.0?±?0.4 mmol/mol), p?=?0.02], HOMA-IR (?0.46?±?0.20, p?=?0.001), LDL-cholesterol (?10.36?±?0.10 mmol/l, p?=?0.04) and total/HDL-cholesterol levels (?0.91?±?0.16, p?=?0.03) compared with other groups. We found a significant increase in QUICKI (0.025?±?0.01, p?=?0.004), HOMA of beta cell function (HOMA-B; 11.8?±?12.17, p?=?0.001) and HDL-cholesterol (0.46?±?0.05 mmol/l, p?=?0.03) in the calcium–vitamin D group compared with others.

Conclusions/interpretation

Joint calcium and vitamin D supplementation might improve the glycaemic status and lipid profiles of vitamin D insufficient people with type 2 diabetes. Trial registration: ClinicalTrials.gov NCT01662193 Funding: Clinical Research Council, Isfahan University of Medical Sciences, Isfahan, Iran     

Maternal intake of vitamin D during pregnancy and risk of advanced beta cell autoimmunity and type 1 diabetes in offspring

Aims/hypothesis

We evaluated the intake of vitamin D by pregnant Finnish women and examined associations between maternal intake of vitamin D and the development of advanced beta cell autoimmunity and type 1 diabetes in their offspring.

Methods

The research was carried out within the Diabetes Prediction and Prevention study (DIPP), which is a population-based birth cohort of infants at genetic risk of type 1 diabetes. Mothers of 3,723 infants born between 1997 and 2002 completed a validated 181-item food frequency questionnaire, which included questions on dietary supplements. The offspring were observed at 3 to 12 month intervals for the appearance of autoantibodies associated with type 1 diabetes and for the development of clinical type 1 diabetes.

Results

Maternal mean daily intake of vitamin D was 5.1 µg from food and 1.3 µg from supplements. The maternal intake of vitamin D, either from food or from supplements, was not associated with the risk of advanced beta cell autoimmunity/type 1 diabetes in offspring (HR [95% CI] for intake of vitamin D from food 1.25 [0.80–1.95], for vitamin D intake from supplements 1.05 [0.95–1.16]), or with the risk of type 1 diabetes alone (HR [95% CI] for intake of vitamin D from food 0.84 [0.41–1.72], for vitamin D intake from supplements 1.09 [0.99–1.20]).

Conclusions/interpretation

Maternal intake of vitamin D either from food or supplements during pregnancy is not associated with advanced beta cell autoimmunity/type 1 diabetes or with type 1 diabetes alone in Finnish offspring carrying increased genetic susceptibility to type 1 diabetes.     

Characterisation of rapid progressors to type 1 diabetes among children with HLA-conferred disease susceptibility

Aims/hypothesis

In this study, we aimed to characterise rapid progressors to type 1 diabetes among children recruited from the general population, on the basis of HLA-conferred disease susceptibility.

Methods

We monitored 7410 HLA-predisposed children participating in the Finnish Type 1 Diabetes Prediction and Prevention (DIPP) study for the development of beta cell autoimmunity and type 1 diabetes from birth over a median follow-up time of 16.2 years (range 0.9–21.1 years). Islet cell antibodies (ICA) and autoantibodies to insulin (IAA), GAD (GADA) and islet antigen 2 (IA-2A) were assessed as markers of beta cell autoimmunity. Rapid progression was defined as progression to clinical type 1 diabetes within 1.5 years of autoantibody seroconversion. We analysed the association between rapid progression and demographic and autoantibody characteristics as well as genetic markers, including 25 non-HLA SNPs predisposing to type 1 diabetes.

Results

Altogether, 1550 children (21%) tested positive for at least one diabetes-associated autoantibody in at least two samples, and 248 (16%) of seroconverters progressed to type 1 diabetes by the end of 2015. The median time from seroconversion to diagnosis was 0.51 years in rapid progressors (n = 42, 17%) and 5.4 years in slower progressors. Rapid progression was observed both among young (<5 years) and early pubertal children (>7 years), resulting in a double-peak distribution of seroconversion age. Compared with slower progressors, rapid progressors had a higher frequency of positivity for multiple (≥2) autoantibodies and had higher titres of ICA, IAA and IA-2A at seroconversion, and there was a higher prevalence of the secretor genotype in the FUT2 gene among those carrying the high-risk HLA genotype. Compared with autoantibody-positive non-progressors, rapid progressors were younger, were more likely to carry the high-risk HLA genotype and a predisposing SNP in the PTPN22 gene, had higher frequency of ICA, IAA, GADA and IA-2A positivity and multipositivity, and had higher titres of all four autoantibodies at seroconversion.

Conclusions/interpretation

At seroconversion, individuals with rapid progression to type 1 diabetes were characterised by a younger age, higher autoantibody titres, positivity for multiple autoantibodies and higher prevalence of a FUT2 SNP. The double-peak profile for seroconversion age among the rapid progressors demonstrates for the first time that rapid progression may take place not only in young children but also in children in early puberty. Rapid progressors might benefit from careful clinical follow-up and early preventive measures.

     

A strategy to find gene combinations that identify children who progress rapidly to type 1 diabetes after islet autoantibody seroconversion

We recently developed a novel approach capable of identifying gene combinations to obtain maximal disease risk stratification. Type 1 diabetes has a preclinical phase including seroconversion to autoimmunity and subsequent progression to diabetes. Here, we applied our gene combination approach to identify combinations that contribute either to islet autoimmunity or to the progression from islet autoantibodies to diabetes onset. We examined 12 type 1 diabetes susceptibility genes (INS, ERBB3, PTPN2, IFIH1, PTPN22, KIAA0350, CD25, CTLA4, SH2B3, IL2, IL18RAP, IL10) in a cohort of children of parents with type 1 diabetes and prospectively followed from birth. The most predictive combination was subsequently applied to a smaller validation cohort. The combinations of genes only marginally contributed to the risk of developing islet autoimmunity, but could substantially modify risk of progression to diabetes in islet autoantibody-positive children. The greatest discrimination was provided by risk allele scores of five genes, INS, IFIH1, IL18RAP, CD25, and IL2 genes, which could identify 80 % of islet autoantibody-positive children who progressed to diabetes within 6 years of seroconversion and discriminate high risk (63 % within 6 years; 95 % CI 45–81 %) and low risk (11 % within 6 years; 95 % CI 0.1–22 %; p = 4 × 10^?5) antibody-positive children. Risk stratification by these five genes was confirmed in a second cohort of islet autoantibody children. These findings highlight genes that may affect the rate of the beta-cell destruction process once autoimmunity has initiated and may help to identify islet autoantibody-positive subjects with rapid progression to diabetes.     

Children developing type 1 diabetes before 6 years of age have increased linear growth independent of HLA genotypes

Aims/hypothesis

High birthweight and increased childhood growth are risk factors for type 1 diabetes. Relative birthweight is associated with HLA genotypes that confer a high risk of diabetes. Our aims were to test whether young children prior to clinical onset of type 1 diabetes have increased: (1) birthweight or birth length standard deviation scores (SDS); (2) height development SDS; or (3) BMI SDS during first 18 months of life and whether these parameters are related to HLA genotypes or mid-parental height (MPH).

Methods

Birthweight, birth length, weight and height were obtained from 58 type 1 diabetes children and 155 controls matched for HLA or not in the Diabetes Prediction in Skåne study.

Results

Birth length SDS corrected for MPH was increased in children developing diabetes compared with all (p?p?p?Conclusions/interpretation Birth length SDS was associated with diabetes risk HLA. When corrected for MPH, children developing diabetes were taller at birth than non-HLA- but not taller than HLA-matched controls. Diabetic children had increased MPH-corrected height up to 18 months of age compared with both HLA- and non-HLA-matched controls. High-risk HLA affects prenatal growth, but other factors may explain the increased postnatal linear growth in children developing diabetes.     

Peptide serum markers in islet autoantibody-positive children

Aims/hypothesis

We sought to identify minimal sets of serum peptide signatures as markers for islet autoimmunity and predictors of progression rates to clinical type 1 diabetes in a case–control study.

Methods

A double cross-validation approach was applied to first prioritise peptides from a shotgun proteomic approach in 45 islet autoantibody-positive and -negative children from the BABYDIAB/BABYDIET birth cohorts. Targeted proteomics for 82 discriminating peptides were then applied to samples from another 140 children from these cohorts.

Results

A total of 41 peptides (26 proteins) enriched for the functional category lipid metabolism were significantly different between islet autoantibody-positive and autoantibody-negative children. Two peptides (from apolipoprotein M and apolipoprotein C-IV) were sufficient to discriminate autoantibody-positive from autoantibody-negative children. Hepatocyte growth factor activator, complement factor H, ceruloplasmin and age predicted progression time to type 1 diabetes with a significant improvement compared with age alone.

Conclusion/interpretation

Distinct peptide signatures indicate islet autoimmunity prior to the clinical manifestation of type 1 diabetes and enable refined staging of the presymptomatic disease period.

     

Human enterovirus infections in children at increased risk for type 1 diabetes: the Babydiet study

Aims/hypothesis

The aim of this study was to examine human enteroviruses (HEVs) and other intestinal viruses derived from children who participated in the Babydiet intervention study and to analyse the findings according to the appearance of islet autoantibodies, dietary intervention, maternal type 1 diabetes and clinical symptoms.

Methods

In the Babydiet study the influence of first gluten exposure (6 or 12?months) on the development of islet autoimmunity was investigated in 150 children with increased genetic and familial risk for type 1 diabetes. Blood and stool samples were collected at 3 monthly intervals until the age of 3?years and yearly thereafter. Infections and clinical symptoms were recorded daily for the first year. In the present study, 339 stool samples collected from 104 children during the first year of life were analysed for HEVs and a certain proportion of the samples were analysed for other intestinal viruses.

Results

HEV was detected in 32 (9.4%) samples from 24 (23.1%) children. Altogether 13 serotypes were identified, with HEV-A species being the most common. Children with gastrointestinal symptoms had norovirus (3/11) and sapovirus (1/11) infections in addition to HEV (1/11). Of the 104 children, 22 developed islet autoantibodies. HEV infections were detected in 18% (4/22) and 24% (20/82) of islet-autoantibody-positive and -negative children, respectively (p?=?0.5). The prevalence of HEV was similar in the gluten-exposed groups and in children from mothers with type 1 diabetes or from affected fathers and/or siblings (p?=?1.0 and 0.6, respectively).

Conclusions/interpretation

No correlation was found between the presence of HEV in the first year of life and the development of islet autoantibodies. There was no association between HEV infections and dietary intervention, maternal diabetes or clinical symptoms.     

Vitamin D deficiency as a risk factor for cystic fibrosis-related diabetes in the Scandinavian Cystic Fibrosis Nutritional Study

Aims/hypothesis

Many cystic fibrosis patients are vitamin D-insufficient. Cystic fibrosis-related diabetes is a major complication of cystic fibrosis. The literature suggests that vitamin D might possess certain glucose-lowering properties. We aimed to assess the relationship between vitamin D and cystic fibrosis-related glucose intolerance.

Methods

We enrolled 898 cystic fibrosis patients from Sweden, Norway and Denmark. Vitamin D intake was assessed using a seven-day food record. Serum 25-hydroxyvitamin D (s25OHD) and HbA_1c were measured, and an OGTT was carried out. Multiple linear and logistic regressions were used for HbA_1c and cystic fibrosis-related diabetes/OGTT result as outcome variables, respectively. Each model was controlled for country, and for known cystic fibrosis-related diabetes risk factors: age, sex, genotype, liver dysfunction, long-term corticosteroid treatment, and lung and pancreatic function.

Results

Degree of vitamin D insufficiency (OR 1.36; p?=?0.032) and s25OHD?p?=?0.042) were significant risk factors for cystic fibrosis-related diabetes. Accordingly, HbA_1c value was positively associated with s25OHD?R ²?=?20.5% and p?1c value in paediatric patients (adjusted R ²?=?20.2%; p?=?0.017), but not in adults.

Conclusions/interpretation

Vitamin D status is associated with HbA_1c and diabetes in cystic fibrosis, particularly in children. The study justifies prospective studies on the proposed role of vitamin D deficiency in the pathophysiology of diabetes mellitus.     

Effects of calcium–vitamin D co-supplementation on glycaemic control,inflammation and oxidative stress in gestational diabetes: a randomised placebo-controlled trial

Aims/hypothesis

This study was designed to assess the effects of calcium and vitamin D supplementation on the metabolic status of pregnant women with gestational diabetes mellitus (GDM).

Methods

This randomised placebo-controlled trial was performed at maternity clinics affiliated to Kashan University of Medical Sciences, Kashan, Iran. Participants were 56 women with GDM at 24–28 weeks’ gestation (18 to 40 years of age). Subjects were randomly assigned to receive calcium plus vitamin D supplements or placebo. All study participants were blinded to group assignment. Individuals in the calcium–vitamin D group (n?=?28) received 1,000 mg calcium per day and a 50,000 U vitamin D₃ pearl twice during the study (at study baseline and on day 21 of the intervention), and those in the placebo group (n?=?28) received two placebos at the mentioned times. Fasting blood samples were taken at study baseline and after 6 weeks of intervention.

Results

The study was completed by 51 participants (calcium–vitamin D n?=?25, placebo n?=?26). However, as the analysis was based on an intention-to-treat approach, all 56 women with GDM (28 in each group) were included in the final analysis. After the administration of calcium plus vitamin D supplements, we observed a significant reduction in fasting plasma glucose (?0.89?±?0.69 vs +0.26?±?0.92 mmol/l, p?p?=?0.02) and HOMA-IR (?0.91?±?1.18 vs +0.63?±?2.01, p?=?0.001) and a significant increase in QUICKI (+0.02?±?0.03 vs ?0.002?±?0.02, p?=?0.003) compared with placebo. In addition, a significant reduction in serum LDL-cholesterol (?0.23?±?0.79 vs +0.26?±?0.74 mmol/l, p?=?0.02) and total cholesterol: HDL-cholesterol ratio (?0.49?±?1.09 vs +0.18?±?0.37, p?=?0.003) and a significant elevation in HDL-cholesterol levels (+0.15?±?0.25 vs ?0.02?±?0.24 mmol/l, p?=?0.01) was seen after intervention in the calcium–vitamin D group compared with placebo. In addition, calcium plus vitamin D supplementation resulted in a significant increase in GSH (+51.14?±?131.64 vs ?47.27?±?203.63 μmol/l, p?=?0.03) and prevented a rise in MDA levels (+0.06?±?0.66 vs +0.93?±?2.00 μmol/l, p?=?0.03) compared with placebo.

Conclusions/interpretation

Calcium plus vitamin D supplementation in women with GDM had beneficial effects on their metabolic profile.

Trial registration

www.irct.ir IRCT201311205623N11

Funding

The study was supported by a grant (no. 92110) from Kashan University of Medical Sciences.     

Association between maternal folate concentrations during pregnancy and insulin resistance in Indian children

Aims/hypothesis

In an Indian birth cohort, higher maternal homocysteine concentration in pregnancy was associated with lower birthweight of the offspring. Lower maternal vitamin B12 and higher folate concentrations were associated with higher offspring insulin resistance. Disordered one-carbon metabolism during early development may increase later metabolic risk. We explored these associations in another birth cohort in India at three age points.

Methods

We measured plasma vitamin B12, folate and homocysteine concentrations at 30?±?2 weeks’ gestation in 654 women who delivered at one hospital. Neonatal anthropometry was recorded, and the children’s glucose and insulin concentrations were measured at 5, 9.5 and 13.5 years of age. Insulin resistance was estimated using HOMA of insulin resistance (HOMA-IR).

Results

Maternal homocysteine concentrations were inversely associated with all neonatal anthropometric measurements (p?<?0.05), and positively associated with glucose concentrations in the children at 5 (30 min; p?=?0.007) and 9.5 years of age (120 min; p?=?0.02). Higher maternal folate concentrations were associated with higher HOMA-IR in the children at 9.5 (p?=?0.03) and 13.5 years of age (p?=?0.03). Maternal vitamin B12 concentrations were unrelated to offspring outcomes.

Conclusions/interpretation

Maternal vitamin B12 status did not predict insulin resistance in our cohort. However, associations of maternal homocysteine and folate concentrations with birth size, and with childhood insulin resistance and glycaemia in the offspring, suggest a role for nutritionally driven disturbances in one-carbon metabolism in fetal programming of diabetes.     

The effect of different doses of vitamin D3 on markers of vascular health in patients with type 2 diabetes: a randomised controlled trial

Aims/hypothesis

Low 25-hydroxyvitamin D levels predict future cardiovascular events and are common in patients with type 2 diabetes. We compared the effect of 100,000 and 200,000 IU doses of vitamin D₃ on endothelial function, blood pressure and markers of glycaemic control in patients with type 2 diabetes.

Methods

This was a randomised, parallel group, placebo-controlled trial. Patients with type 2 diabetes and baseline 25-hydroxyvitamin D levels <100 nmol/l were enrolled from community and hospital-based diabetes clinics. Participants were assessed in a university department of clinical pharmacology and received a single oral dose of placebo or vitamin D₃ (100,000 IU or 200,000 IU) at baseline, randomly allocated via numbered bottles prepared offsite; participants and investigators were both blinded to treatment allocation. Endothelial function, office blood pressure, B-type natriuretic peptide, insulin resistance and glycosylated haemoglobin were measured at baseline, and at 8 and 16 weeks.

Results

We randomised 61 participants to the three groups (placebo 22, 100,000 IU vitamin D₃ 19, 200,000 IU vitamin D₃ 20). There was no significant difference in the primary outcome of endothelial function at 8 weeks (placebo 5.2%, n?=?22; 100,000 IU 4.3%, n?=?19; 200,000 IU 4.9%, n?=?17) or at 16 weeks. Insulin resistance and glycosylated haemoglobin did not improve with either dose of vitamin D₃. On covariate analysis, systolic blood pressure was significantly lower in both treatment arms than in the placebo group at 8 weeks (placebo 146.4 mmHg, 100,000 IU 141.4 mmHg [p?=?0.04 vs placebo], 200,000 IU 136.8 mmHg [p?=?0.03 vs placebo]). B-type natriuretic peptide levels were significantly lower in the 200,000 IU group by 16 weeks (placebo 34 pg/ml, 200,000 IU 21 pg/ml, p?=?0.02). No significant excess of adverse effects was noted in the treatment arms.

Conclusions/interpretation

High-dose vitamin D₃ improved systolic blood pressure and B-type natriuretic peptide levels, but not endothelial function, insulin resistance or glycosylated haemoglobin in patients with type 2 diabetes.

Trial registration

ISRCTN50587697 (www.controlled-trials.com)

Funding

Diabetes UK, grant number 06/0003429. M. D. Witham is funded by a Scottish Government NES/CSO Clinician Scientist Award.     

Vitamin D Deficiency Is Associated with Ulcerative Colitis Disease Activity

Purpose

Previous studies on experimental mouse models have suggested a role of vitamin D in immune system regulation and IBD disease severity. In this study, we examine the relationship between vitamin D levels and clinical disease activity in human subjects with ulcerative colitis (UC). We hypothesized that patients with vitamin D deficiency will display increased UC disease activity as compared to patients with normal vitamin D levels.

Methods

A cross-sectional study was performed by querying the outpatient electronic medical record of our health system for patients seen in the gastroenterology clinic from January 2007 to October 2009 who carried both a diagnosis of UC and a documented 25-OH vitamin D level within 30 days of their clinic visit. Demographic and clinical variables were collected. Clinical disease activity was calculated using the six-point partial Mayo index. Active disease was defined as a six-point index score of ≥1. Vitamin D deficiency was defined as a 25-OH D level below 30 ng/ml. Data were analyzed using the chi-square distribution test.

Results

Thirty-four patients met inclusion criteria (53 % female, mean age 45.7 ± 24.7 years). Fifteen patients had normal vitamin D levels and 19 patients were vitamin D deficient. Twelve patients had vitamin D levels <20 ng/ml. Vitamin D deficient patients were statistically more likely to have increased disease activity than patients with normal vitamin D levels (p = 0.04), with 68 % of deficient patients displaying active disease compared with 33 % in the sufficient group. There was also a statistically significant association between vitamin D status and need for treatment with steroids, with a higher percentage of vitamin D deficient patients (47 %) requiring such treatment compared with 7 % in the sufficient group (p = 0.02). There was no association between season of visit and disease activity.

Conclusion

Vitamin D deficiency is common among patients with active UC, particularly those requiring corticosteroids. Further investigation is needed to determine the clinical utility of vitamin D monitoring in patients with UC and whether there is a role for vitamin D as a treatment for UC.     

Microvascular autoregulation in children and adolescents with type 1 diabetes mellitus

Aims/hypothesis

Deterioration of microvascular function may have an early onset in individuals with type 1 diabetes mellitus. We hypothesised that microvascular autoregulation is impaired in children with type 1 diabetes and can be detected non-invasively by postocclusive reactive hyperaemia (PORH).

Methods

Microvascular autoregulation was assessed in 58 children with type 1 diabetes and 58 age- and sex-matched healthy controls by PORH using laser Doppler fluxmetry. Baseline perfusion, biological zero (defined as a ‘no flow’ laser Doppler signal during suprasystolic occlusion), peak perfusion following occlusion, time to peak and recovery time (time until baseline perfusion is resumed) were recorded and compared between the groups.

Results

Peak perfusion was higher in children with type 1 diabetes than in healthy controls (1.7?±?0.93?AU [arbitrary units] vs 1.29?±?0.46?AU; p?=?0.004), and biological zero was lower in children with type 1 diabetes vs controls (0.14?±?0.04?AU vs 0.19?±?0.04?AU; p?Conclusions/interpretation PORH reveals impaired microvascular autoregulation in children with type 1 diabetes. The higher peak perfusion might reflect a decline in the vasoconstrictive ability of arteriolar smooth muscle cells upstream of capillary beds in children with type 1 diabetes.     

Vitamin D modulates biliary fibrosis in ABCB4-deficient mice

Purpose

Impaired vitamin D receptor signaling represents an aggravating factor during liver injury, and recent studies suggest that vitamin D might exert a protective role in chronic hepatobiliary diseases. We hypothesized that vitamin D supplementation would ameliorate liver fibrosis in ATP-binding cassette transporter B4 knockout (Abcb4 ^?/?) mice as a preclinical model of sclerosing cholangitis.

Methods

Abcb4 ^?/? and wild-type mice were fed a regular chow diet (600 IU vitamin D/kg food) or diets with lower (100 IU/kg) and higher (2,400 IU/kg) vitamin D concentrations for 12 weeks. Serum 25-hydroxyvitamin D concentrations were measured by chemiluminescence immunoassays. Liver injury and biliary fibrosis were assessed by liver enzyme activities, histopathology and hepatic collagen contents. Hepatic mRNA expression of markers for fibrosis, vitamin D and bile acid metabolism were analyzed by quantitative PCR.

Results

Different vitamin D concentrations were observed depending on genotype and diet group, with Abcb4 ^?/? mice on the control diet showing lower vitamin D concentrations compared to wild-type mice. Abcb4 ^?/? animals on the low vitamin D diet demonstrated the most advanced liver fibrosis and highest hepatic collagen contents. Feeding Abcb4 ^?/? mice a high vitamin D diet enriched serum vitamin D levels, lowered liver enzyme activities, altered expression levels of profibrogenic genes and ameliorated, in part, liver injury.

Conclusions

This is the first report to demonstrate that fibrogenesis in the established Abcb4 ^?/? model is influenced by vitamin D supplementation. Since vitamin D modulates sclerosing cholangitis in vivo, we speculate that sufficient vitamin D intake might improve liver damage and induce antifibrotic effects in chronic cholestasis in humans.