The risk of developing islet autoimmunity and type 1 diabetes declines exponentially with age. This is the result of a recent analysis of the TEDDY study, which has now been published in Diabetes Care. The new findings may also improve screening for pre-symptomatic type 1 diabetes.  

Islet autoimmunity develops before clinical type 1 (T1D) diabetes and includes multiple and single autoantibody phenotypes. The objective was to determine age-related risks of islet autoantibodies that reflect etiology and improve screening for pre-symptomatic T1D. For this purpose, the researchers prospectively monitored 8,556 genetically at-risk children at 3- to 6-month intervals from birth for the development of islet autoantibodies and T1D.  

The results showed that the 5-year risk of developing multiple islet autoantibodies was 4.3 per cent at 7.5 months of age. At an age of just over six years, it declined to 1.1 percent. The authors of the study therefore suspect that the risk of developing islet autoimmunity declines exponentially with age and the influence of major genetic factors on this risk is limited to the first few years of life. 

The new findings may also help to improve screening for pre-symptomatic T1D. The study showed that testing twice for islet autoantibodies, first at two years of age and then again at 5-7 years of age, had the highest sensitivity and positive predictive value of multiple islet autoantibody phenotypes for T1D. 

According to the authors, one strength of the current evaluation is the large number of robust data collected in the TEDDY study. One limitation is that all TEDDY children have a certain genetic constellation, which was determined as an inclusion criterion for the TEDDY study. Thus, the study population does not quite correspond to the general population. 

Original publication: 
Bonifacio, E. et al.: An age-related exponential decline in the risk of multiple islet autoantibody seroconversion during childhood. DOI:  https://doi.org/10.2337/dc20-2122 

*About the TEDDY study
The TEDDY study (The Environmental Determinants of Diabetes in the Young), is an international research project (USA, Finland, Germany and Sweden) that investigates the possible risk factors for the development of type 1 diabetes. More than 8,600 newborns with an increased genetic risk for T1D were included in the study and closely monitored until their teenage years. The vast majority of the participating children (89 percent) had no close relatives with type 1 diabetes. 
https://teddy.epi.usf.edu