Spiros Fourlanos

The Rising Incidence of Type 1 Diabetes Is Accounted for by Cases With Lower-Risk Human Leukocyte Antigen Genotypes

OBJECTIVE—The rising incidence of type 1 diabetes has been attributed to environment, implying a lesser role for genetic susceptibility. However, the rise could be accounted for by either more cases with classic high-risk genes or by cases with other risk genes. Separately, for any degree of genetic susceptibility, age at presentation may decrease in a permissive environment. To examine these possibilities, human leukocyte antigen (HLA) class II DRB1 genes known to confer risk for type 1 diabetes were analyzed in relation to year of birth and age at diagnosis over the last five decades. RESEARCH DESIGN AND METHODS—Caucasoid subjects (n = 462) diagnosed with type 1 diabetes before age 18 between 1950 and 2005 were DRB1 genotyped. RESULTS—Mean ± SD age at diagnosis, 8.5 ± 4.5 years, did not differ across decades. Recent diagnosis was associated with a lower proportion but unchanged incidence of the highest-risk DRB1 genotype DR3,4 (2000–2005, 28% vs. 1950–1969, 79%; P < 0.0001) and a higher proportion of lower-risk genotypes DR4,X and DR3,X (2000–2005, 48% vs. 1950–1969, 20%; P = 0.0002). The frequency of the DRX,X genotype was low (≤3%) across decades. Recent birth was associated with a lower age at diagnosis for lower risk DR3,3 and DR4,4 (P < 0.0001) and DR4,X (P < 0.0001) and DR3,X (P = 0.015) genotypes but not for DR3,4. CONCLUSIONS—The rising incidence and decreasing age at diagnosis of type 1 diabetes is accounted for by the impact of environment on children with lower-risk HLA class II genes, who previously would not have developed type 1 diabetes in childhood.

Evidence That Nasal Insulin Induces Immune Tolerance to Insulin in Adults With Autoimmune Diabetes

OBJECTIVE Insulin in pancreatic β-cells is a target of autoimmunity in type 1 diabetes. In the NOD mouse model of type 1 diabetes, oral or nasal administration of insulin induces immune tolerance to insulin and protects against autoimmune diabetes. Evidence for tolerance to mucosally administered insulin or other autoantigens is poorly documented in humans. Adults with recent-onset type 1 diabetes in whom the disease process is subacute afford an opportunity to determine whether mucosal insulin induces tolerance to insulin subsequently injected for treatment. RESEARCH DESIGN AND METHODS We randomized 52 adults with recent-onset, noninsulin-requiring type 1 diabetes to nasal insulin or placebo for 12 months. Fasting blood glucose and serum C-peptide, glucagon-stimulated serum C-peptide, and serum antibodies to islet antigens were monitored three times monthly for 24 months. An enhanced ELISpot assay was used to measure the T-cell response to human proinsulin. RESULTS β-Cell function declined by 35% overall, and 23 of 52 participants (44%) progressed to insulin treatment. Metabolic parameters remained similar between nasal insulin and placebo groups, but the insulin antibody response to injected insulin was significantly blunted in a sustained manner in those who had received nasal insulin. In a small cohort, the interferon-γ response of blood T-cells to proinsulin was suppressed after nasal insulin. CONCLUSIONS Although nasal insulin did not retard loss of residual β-cell function in adults with established type 1 diabetes, evidence that it induced immune tolerance to insulin provides a rationale for its application to prevent diabetes in at-risk individuals.

New‐Onset Diabetes After Kidney Transplantation—Changes and Challenges

Despite substantial improvement in short‐term results after kidney transplantation, increases in long‐term graft survival have been modest. A significant impediment has been the morbidity and mortality attributable to cardiovascular disease (CVD). New‐onset diabetes after transplantation (NODAT) is an independent predictor of cardiovascular events. This review examines recent literature surrounding diagnosis, outcomes and management of NODAT. Amongst otherwise heterogeneous studies, a common finding is the relative insensitivity of fasting blood glucose (FBG) as a screening test. Incorporating self‐testing of afternoon capillary BG and glycohemoglobin (HbA1c) detects many cases that would otherwise remain undetected without the oral glucose tolerance test (OGTT). Assessing the impact of NODAT on patient and graft survival is complicated by changes to diagnostic criteria, evolution of immunosuppressive regimens and increasing attention to cardiovascular risk management. Although recent studies reinforce a link between NODAT and death with a functioning graft (DWFG), there seems to be little effect on death‐censored graft loss. The significance of glycemic control and diabetes resolution for patient outcomes remain notably absent from NODAT literature and treatment is also a neglected area. This review examines new and old therapeutic options, emphasizing the need to assess β‐cell pathology in customizing therapy. Finally, areas warranting further research are considered.

The accelerator hypothesis and increasing incidence of type 1 diabetes.

Purpose of reviewTo summarize the relevance of the ‘accelerator hypothesis’ to type 1 diabetes pathogenesis and examine if recent evidence supports the hypothesis. The ‘accelerator hypothesis’ proposes ‘three processes in type 1 diabetes which variably accelerate the loss of beta cells through apoptosis: constitution, insulin resistance and autoimmunity’. Recent findingsInsulin resistance is an independent risk factor for progression to clinical type 1 diabetes in people with islet autoimmunity. Higher bodyweight is also associated with type 1 diabetes development although no longitudinal studies have simultaneously assessed bodyweight and insulin resistance in preclinical diabetes. Currently, there is no evidence for the view that accelerated beta-cell apoptosis is due to insulin resistance in the pathogenesis of type 1 diabetes. SummaryInsulin resistance accelerates development of type 1 diabetes in people with islet autoimmunity and insulin deficiency. The increasingly ‘obesogenic’ environment which promotes insulin resistance could account for the rising incidence of type 1 diabetes.

Lipid Lowering Agents, Cognitive Decline, and Dementia: The Three-City Study

The aim of this prospective cohort study was to evaluate the effects of lipid lowering agent (LLA) intake on cognitive function in 6,830 community-dwelling elderly persons. Cognitive performance (global cognitive functioning, visual memory, verbal fluency, psychomotor speed, and executive function), clinical diagnosis of dementia, and fibrate and statin use, were evaluated at baseline, and 2, 4, and 7 year follow-up. Multivariate Cox models were stratified by gender and adjusted for sociodemographic characteristics, mental and physical health including vascular risk factors, and genetic vulnerability (apolipoprotein E and cholesteryl ester transfer protein). For women but not men, fibrate use was specifically associated with an increased risk over 7 years of decline in visual memory only (HR = 1.29, 95% CI = 1.09-1.54, p = 0.004), and did not increase risk for incident dementia. This association was independent of genetic vulnerability related to apolipoprotein E and cholesteryl exchange transfer protein polymorphisms and occurred only in women with higher low density lipoprotein (LDL)-cholesterol levels and treated with fibrate (HR = 1.39, 95% CI = 1.08-1.79, p = 0.01) and not in those with lower LDL-cholesterol levels irrespective of fibrate treatment. For both genders, no significant associations were found between statins (irrespective of their lipophilicity) and either cognitive decline or dementia incidence. This prospective study, adjusting for multiple confounders, found no evidence that LLA given in late life reduced the risk of cognitive decline and dementia, but did raise the possibility that women with treatment-resistant high LDL-cholesterol may be at increased risk of decline in visual memory.

Screening for new-onset diabetes after kidney transplantation: limitations of fasting glucose and advantages of afternoon glucose and glycated hemoglobin.

Background The sensitivity of fasting plasma glucose (FPG) in screening for new-onset diabetes after transplantation (NODAT) has been questioned, particularly in the presence of moderate-dose prednisolone, where peak plasma glucose occurs 7 to 8 hr after administration. Oral glucose tolerance testing (OGTT) has been mooted as an alternative but is inconvenient for patients. Methods We compared sensitivity of screening tests for NODAT at 6 weeks, 3 months, and 12 months after kidney transplantation in recipients receiving prednisolone, mycophenolate, and tacrolimus. Results At 6 weeks, NODAT (capillary blood glucose [CapBG] ≥11.1 mmol/L, FPG ≥7.0 mmol/L, 2-hr plasma glucose ≥11.1 mmol/L, or glycated hemoglobin [HbA1c] ≥6.5%) was detected in 46% with CapBG versus 12% with OGTT (P=0.013), 4% with HbA1c (P<0.001), and 0% with FPG (P<0.001; n=26). At 3 months, NODAT was present in 14% with HbA1c versus 20% with OGTT (P=0.600) and 2% with FPG (P=0.059; n=50), whereas, at 12 months, NODAT was found in 4% with HbA1c versus 6% with OGTT (P=1.00) and 2% with FPG (P=0.618; n=51). Combining 3- and 12-month data, OGTT recorded NODAT in 14% and impaired glucose tolerance in 28%, whereas HbA1c detected NODAT in 10% and impaired glucose tolerance (from ≥5.7 to <6.5%) in 51%. Employing HbA1c as a screening test and reserving OGTT for those with impaired glucose tolerance would detect NODAT with a sensitivity more than 94%, avoiding the need for OGTT in 49% of patients. Conclusions This study confirms the inadequacy of FPG screening for NODAT in the first 6 weeks after transplantation, at which time 4 p.m. CapBG also outperformed OGTT. From 3 months, HbA1c had similar sensitivity to OGTT and represents a convenient alternative.

A randomised controlled trial of high dose vitamin D in recent-onset type 2 diabetes

AIMS Vitamin D insufficiency has been associated with impaired pancreatic beta-cell function. We aimed to determine if high dose oral vitamin D3 (D) improves beta-cell function and glycaemia in type 2 diabetes. METHODS Fifty adults with type 2 diabetes diagnosed less than 12 months, with normal baseline serum 25-OH D (25D), were randomised to 6000 IU D (n=26) or placebo (n=24) daily for 6 months. Beta-cell function was measured by glucagon-stimulated serum C-peptide (delta C-peptide [DCP], nmol/l). Secondary outcome measures were fasting plasma glucose (FPG), post-prandial blood glucose (PPG), HbA1c and insulin resistance (HOMA-IR). RESULTS In the D group, median serum 25D (nmol/l) increased from 59 to 150 (3 months) and 128 (6 months) and median serum 1,25D (pmol/l) from 135 to 200 and 190. After 3 months, change in DCP from baseline in D (+0.04) and placebo (-0.08) was not different (P=0.112). However, change in FPG (mmol/l) was significantly lower in D (-0.40) compared to placebo (+0.1) (P=0.007), as was the change in PPG in D (-0.30) compared to placebo (+0.8) (P=0.005). Change in HbA1c (%) between D (-0.20) and placebo (-0.10) was not different (P=0.459). At 6 months, changes from baseline in DCP, FPG, PPG and HbA1c were not different between groups. CONCLUSION Oral D3 supplementation in type 2 diabetes was associated with transient improvement in glycaemia, but without a measurable change in beta-cell function this effect is unlikely to be biologically significant. High dose D3 therefore appears to offer little or no therapeutic benefit in type 2 diabetes.

Divided dosing reduces prednisolone-induced hyperglycaemia and glycaemic variability: a randomized trial after kidney transplantation

BACKGROUND Prednisolone is a major risk factor for hyperglycaemia and new-onset diabetes after transplantation. Uncontrolled observational data suggest that divided dosing may reduce requirements for hypoglycaemic agents. This study aims to compare the glycaemic effects of divided twice daily (BD) and once daily (QD) prednisolone. METHODS Twenty-two kidney transplant recipients without diabetes were randomized to BD or QD prednisolone. Three weeks post-transplant, a continuous glucose monitor (iPro2(®) Medtronic) was applied for 5 days with subjects continuing their initial prednisolone regimen (Days 1-2) before crossover to the alternative regimen. Mean glucose, peak glucose, nadir glucose, exposure to hyperglycaemia (glucose ≥7.8 mmol/L) and glycaemic variability were assessed. RESULTS The mean ± standard deviation (SD) age of subjects was 50 ± 10 years and 77% were male. Median (interquartile range) daily prednisolone dose was 25 (20, 25) mg. BD prednisolone was associated with decreased mean glucose (mean 7.9 ± 1.7 versus 8.1 ± 2.3 mmol/L, P < 0.001), peak glucose [median 10.4 (9.5, 11.4) versus 11.4 (10.3, 13.4) mmol/L, P< 0.001] and exposure to hyperglycaemia [median 25.5 (14.6, 30.3) versus 40.4 (33.2, 51.2) mmol/L/h, P = 0.003]. Median glucose peaked between 14:55-15.05 h with BD and 15:25-15:30 h with QD. Median glycaemic variability scores were decreased with BD: SD (1.1 versus 1.9, P < 0.001), mean amplitude of glycaemic excursion (1.5 versus 2.2, P = 0.001), continuous overlapping net glycaemic action-1 (CONGA-1; 1.0 versus 1.2, P = 0.039), CONGA-2 (1.2 versus 1.4, P = 0.008) and J-index (25 versus 31, P = 0.003). CONCLUSIONS Split prednisolone dosing reduces glycaemic variability and hyperglycaemia early post-kidney transplant.

Obesity is associated with retinopathy and macrovascular disease in type 1 diabetes

Excessive body weight is increasingly seen in type 1 diabetes but its impact is debated. To address this uncertainty, we aimed to determine the association between excess body weight and the macro- and microvascular complications of type 1 diabetes. We identified 501 adults with type 1 diabetes attending an Australian hospital clinic and extracted their clinical and biochemical data from our patient management database. In both men and women, obesity (BMI > 30 kg/m(2)) was the predominant risk factor for retinopathy and cardiovascular disease despite similar HbA1c and increased use of cardioprotective drugs compared to non-obese patients. Obesity was associated with albuminuria in women, but not renal impairment or neuropathy in either sex. We conclude that obesity in type 1 diabetes may promote retinopathy and macrovascular disease. Future trials to determine the effect of weight loss on type 1 diabetes in obese people are needed.

Higher body mass index in adults at diagnosis of the slowly progressive form of type 1 diabetes mellitus is associated with lower risk HLA genes

We hypothesised that higher body weight, a proposed risk factor for type 1 diabetes mellitus, would be associated with increased penetrance of lower risk genes. In adults at diagnosis of the slowly progressive form of type 1 diabetes mellitus we found that higher body mass index was associated with the absence of the highest risk HLA genes.