Autoimmune reaction against pancreatic beta cells in children and adolescents with simple obesity.

Introduction: One of the most important complications of obesity is insulin resistance, which leads to carbohydrate metabolism disorders such as type 2 diabetes. However, obesity is also associated with development of an autoimmune response against various organs, including pancreatic beta cells. The prevalence of such autoimmune processes in children and their possible contribution to the increased incidence of type 1 diabetes is currently unclear. Therefore, the present study assessed the prevalence of autoantibodies against pancreatic islet beta cell's antigens in children and adolescents with simple obesity. Material and methods: This prospective observational study included pediatric patients (up to 18 years of age) with simple obesity hospitalized between 2011 and 2016 at the Department of Pediatrics, Diabetology, Endocrinology and Nephrology of the Medical University of Lodz. Children with acute or chronic conditions that might additionally affect insulin resistance or glucose metabolism were excluded. Collected clinical data included sex, age, sexual maturity ratings (Tanner`s scale), body height and weight, waist and hip circumference, amount of body fat and lean body mass. Each participant underwent a 2-hour oral glucose tolerance test with simultaneous measurements of glycaemia and insulinemia at 0`, 60` and 120`. In addition, glycated hemoglobin HbA1c, fasting and stimulated c-peptide, total cholesterol, as well as high- and low-density cholesterol and triglycerides were measured. Insulin resistance was assessed by calculating HOMA-IR index. The following autoantibodies against pancreatic islet beta cells were determined in each child: ICA - antibodies against cytoplasmic antigens of pancreatic islets, GAD - antibodies against glutamic acid decarboxylase, ZnT8 - antibodies against zinc transporter, IA2 - antibodies against tyrosine phosphatase, IAA - antibodies against insulin. Results: The study group included 161 children (57.4% boys, mean age 13.1 ± 2.9 years) with simple obesity (mean BMI z-score +2.2 ± 1.6). Among them, 28 (17.4%) were diagnosed with impaired glucose metabolism during OGTT [23 (82.2%) - isolated impaired glucose tolerance (IGT), 3 (10.7%) - isolated impaired fasting glucose (IFG), 2 (7.1%) - IFG and IGT]. Of the children tested, 28 (17.4%) were tested positive for at least one islet-specific autoantibody [with similar percentages in boys (15, 17.4%) and girls (13, 17.3%), p=0.9855], with ICA being the most common (positive in 18, 11.2%), followed by IAA (7, 4.3%), ZnT8 (5, 3.1%), GADA (3, 1.9%) and IA2 (1, 0.6%). There was no association between the presence of the tested antibodies and age, sex, stage of puberty, parameters assessing the degree of obesity, HbA1c, lipid levels and basal metabolic rate. However, autoantibody-positive subjects were more likely to present IFG or IGT in OGTT compared to those who tested completely negative (9, 32.1% vs 19, 14.3%, p=0.0280). Their HOMA-IR was also significantly higher (HOMA-IR: 4.3 ± 1.9 vs 3.4 ± 1.9, p=0.0203) and this difference remained statistically significant after adjusting for sex and age (p=0.0340). Conclusions: Children and adolescents with simple obesity presented a higher prevalence of markers of autoimmune response against pancreatic beta cells than the general population. Most often, they had only one type of antibody - ICA. The presence of autoimmune response indicators against pancreatic islet antigens is more common in obese patients with impaired carbohydrate metabolism and is associated with lower insulin sensitivity.

Incidence of hyperglycaemic disorders in children and adolescents with obesity.

INTRODUCTION: The prevalence of obesity in the paediatric population has increased significantly in recent decades. To date, the rarest metabolic disturbance associated with obesity has been the hyperglycaemia, including diabetes. The aim of the study was to compare the prevalence of hyperglycaemic disorders diagnosed on the basis of (1) the oral glucose tolerance test (OGTT) and (2) the HbA1c value, and to estimate the prevalence of hyperglycaemia in continuous glucose monitoring (CGM) records in adolescents with obesity. MATERIAL AND METHODS: The study included patients aged 9-18 years with obesity (BMI ≥ 95th percentile). The height, body weight, and waist circumference were measured, and the BMI and BMI Z-score were calculated. Sexual maturity was assessed on the Tanner scale. OGTT was performed, and the HbA1c value was measured. Six-day retrospective blinded CGM was performed. RESULTS: In the group of 143 children (mean age 13.4 years), the severity of obesity positively increased with patients age (r = 0.36 and p < 0.0001). Abdominal obesity was found in 93.4% of children. Based on OGTT, 18.8% of the subjects had hyperglycaemic disorders; impaired glucose tolerance was the most common one (16.1%). Impaired fasting glucose was found in 4 patients (2.8%), and type 2 diabetes was found in 2. The mean HbA1c was 5.4%. HbA1c values ranged from 5.7 to 6.4% in 20.3% of the patients, and it did not exceed 6.4% in any patient. In 27.6% of patients with HbA1c 5.7-6.4%, abnormalities in OGTT were observed (IGT 17.25%, IFG 6.9%, DM2 3.45%). There was a significant discrepancy between OGTT results and HbA1c in the diagnosis of hyperglycaemic disorders (diagnosis agreement - 69.92%). In CGM 1.4% of results were above 140 mg/dl. CONCLUSIONS: Hyperglycaemic disorders are diagnosed in nearly 20% of children with obesity. However, there are significant discrepancies in the diagnosis of glucose disturbances using OGTT and HbA1c. Concordance in the diagnosis of hyperglycaemic disorders was achieved only in 70% of patients. CGM may be useful in the diagnosis of pre-diabetes in people with obesity.

Achieving target levels for vascular risk parameters in Polish school-age children with type 1 diabetes - a single center study.

Background Therapeutic goals have been established to decrease the risk of long-term complications of type 1 diabetes (T1DM). The effects of these guidelines should be constantly evaluated. Hence, the present study examines the frequency at which children with T1DM treated by one of the Polish reference centers complied with the therapeutic targets issued in 2014 by the International Society for Pediatric and Adolescent Diabetes (ISPAD) and by the Diabetes Poland (PTD). Methods A retrospective analysis (years 2011-2014) was performed in patients with T1DM aged 6.5-18 years, with diabetes duration >12 months and no change of insulin regimen within 6 months. Collected data included insulin therapy regimen, weight, height, blood pressure, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG) and glycated hemoglobin (HbA1c) level from the last hospitalization. Results The records of 447 patients (260 boys, 299 treated with insulin pump) were analyzed. All ISPAD goals were achieved by 123 (27.5%) patients, but only 43 (9.6%) met all PTD targets. Optimal HbA1c was achieved by 224 (50.1%) according to ISPAD criteria (HbA1c<7.5%) and by 87 (19.6%) patients according to PTD (HbA1c≤6.5%). Obesity was diagnosed in 11.6% of the patients; 19.7% of the patients were overweight. In logistic regression, patient age was the only independent predictor of failing to achieve complete T1DM control (p=0.001, OR=1.12 [1.05-1.23]) and optimal HbA1c (p=0.01, OR=1.1 [1.0-1.2]) according to ISPAD guidelines. Moreover, girls had a greater risk of failing body mass index (BMI) targets (PTD: p=0.002, OR=2.16; ISPAD: p=0.0001, OR=3.37) and LDL-C targets (p=0.005, OR=1.8) than boys. Conclusions Overall, control of vascular risk factors in Polish children with T1DM is unsatisfactory. While too few children are achieving the HbA1c target set by PTD, it is possible that such strict national target helps half of the Polish school-age patients achieve ISPAD-issued aim which is more liberal. High prevalence of overweight among children with T1DM warrants initiatives focused not only on glycemic control but also on motivation of patients to lead a healthy lifestyle.