Update on Worldwide Efforts to Prevent Type 1 Diabetes

This paper reviews worldwide efforts to interdict the type 1 diabetes (T1D) disease process, during the stage of evolution of the disease prior to the time of disease onset. The goal of intervention before disease onset is to arrest immune destruction and thus prevent or delay clinical disease. In this regard, there have been several large-scale multicenter randomized controlled clinical trials designed to prevent T1D. These have tested nicotinamide, parenteral insulin, oral insulin, nasal insulin, and the elimination of cow's milk from infant feeding

European Nicotinamide Diabetes Intervention Trial (ENDIT): a randomised controlled trial of intervention before the onset of type 1 diabetes

BACKGROUND: Results of studies in animals and human beings suggest that type 1 diabetes is preventable. Nicotinamide prevents autoimmune diabetes in animal models, possibly through inhibition of the DNA repair enzyme poly-ADP-ribose polymerase and prevention of beta-cell NAD depletion. We aimed to assess whether high dose nicotinamide prevents or delays clinical onset of diabetes in people with a first-degree family history of type 1 diabetes. METHOD: We did a randomised double-blind placebo-controlled trial of nicotinamide in 552 relatives with confirmed islet cell antibody (ICA) levels of 20 Juvenile Diabetes Federation (JDF) units or more, and a non-diabetic oral glucose tolerance test. Participants were recruited from 18 European countries, Canada, and the USA, and were randomly allocated oral modified release nicotinamide (1.2 g/m2) or placebo for 5 years. Random allocation was done with a pseudorandom number generator and we used size balanced blocks of four and stratified by age and national group. Primary outcome was development of diabetes, as defined by WHO criteria. Analysis was done on an intention-to-treat basis. FINDINGS: There was no difference in the development of diabetes between the treatment groups. Of 159 participants who developed diabetes in the course of the trial, 82 were taking nicotinamide and 77 were on placebo. The unadjusted hazard ratio for development of diabetes was 1.07 (95% CI 0.78-1.45; p=0.69), and the hazard ratio adjusted for age-at-entry, baseline glucose tolerance, and number of islet autoantibodies detected was 1.01 (0.73-1.38; p=0.97). Of 168 (30.4%) participants who withdrew from the trial, 83 were on placebo. The number of serious adverse events did not differ between treatment groups. Nicotinamide treatment did not affect growth in children or first-phase insulin secretion. INTERPRETATION: Large-scale controlled trials of interventions designed to prevent the onset of type 1 diabetes are feasible, but nicotinamide was ineffective at the dose we used

Identification of prediabetes in first-degree relatives at intermediate risk of type I diabetes

Prevention trials of type I diabetes are limited by recruitment of individuals at high risk of the disease. We investigated whether demographic and biological characteristics can identify rapid progressors among first-degree relatives of known patients at intermediate (< 10%) 5-year risk. Diabetes-associated antibodies, random proinsulin : C-peptide (PI/C) ratio and HLA DQ genotype were determined (repeatedly) in 258 islet antibody-positive IA-2Antibody-negative (Abpos/IA-2Aneg) normoglycaemic first-degree relatives. During follow-up (median 81 months), 14 of 258 Abpos/IA-2Aneg relatives developed type I diabetes; 13 (93%) of them had persistent antibodies conferring a 12% [95% confidence interval (CI): 5–19%] 5-year risk of diabetes. In Abpos/IA-2Aneg relatives with persistent antibodies (n = 126), the presence of ≥ 1 HLA DQ susceptibility haplotype in the absence of a protective haplotype (P = 0·033) and appearance on follow-up of a high PI/C ratio (P = 0·007) or IA-2A-positivity (P = 0·009) were identified as independent predictors of diabetes. In persistently antibody-positive relatives with HLA DQ risk a recurrently high PI/C ratio or development of IA-2A identified a subgroup (n = 32) comprising 10 of 13 (77%) prediabetic relatives and conferred a 35% (95% CI: 18–53%) 5-year risk. Under age 15 years, 5-year progression (95% CI) was 57% (30–84%) and sensitivity 62%. In the absence of IA-2A, the combination of antibody persistence, HLA DQ risk and elevated PI/C ratio or later development of IA-2A and young age defines a subgroup of relatives with a high risk of type I diabetes (≥ 35% in 5 years). Together with initially IA-2A-positive relatives these individuals qualify for standardized beta cell function tests in view of prevention trials

Primary and secondary prevention of Type 1 diabetes

Since type 1 diabetes is an immunologically mediated disease, immune intervention should alter the natural history of the disease. This article reviews prevention studies undertaken either prior to any evidence of autoimmunity (primary prevention) or after the development of islet autoantibodies (secondary prevention). Most immune intervention studies have been conducted in recent-onset type 1 diabetes (tertiary prevention), and these are not reviewed herein. The goal of primary and secondary intervention is to arrest the immune process and thus prevent or delay clinical disease. Primary prevention studies have been conducted in infants with high genetic risk. Interventions tested include several dietary manipulations, including infant formulas free of either cow's milk or of bovine insulin, infant formula supplemented with the omega-3-fatty acid docosahexaenoic acid, delayed introduction of gluten-containing foods, and vitamin D supplementation. Secondary prevention studies have been conducted in both children and adults with diabetes autoantibodies. Interventions tested include nicotinamide, insulin injections, oral insulin, nasal insulin, glutamic acid decarboxylase, and cyclosporine. Underway are secondary prevention studies with teplizumab and with abatacept