A new study suggests a link between enteroviruses, and the development of type 1 diabetes (T1D). This study, part-funded by JDRF, isn’t the first to find this link but the authors say it’s the largest and most definitive study of its kind to date.
Professor Keikki HyÖty and Dr Hanna Honkanen led this study published in Diabetologia at the University of Tampere in Finland. They found that children at high risk of T1D who then go on to develop the disease, had a higher number of enterovirus infections compared to those without the disease.
This was a case-control study, nested within a prospective birth cohort of children participating in the Type 1 Diabetes Prediction and Prevention study in Finland.
Stool samples were collected for analysis once a month starting from the age of 3 months up until 2-3 years old. They analysed stool from 129 case children (1673 samples) and 282 control children (3108 samples), using reverse‐transcriptase polymerase chain reaction to detect viral RNA, which was genotyped by sequencing.
The researchers found 108 enterovirus infections in the 129 children with T1D (0.8 infections per child) vs. 169 enterovirus infections in 282 control children (0.6 infections per child). Altogether, 25 different enteroviruses were detected in all of the children’s samples throughout the duration of the study, however no single type of enterovirus showed a particular association with type 1 autoantibodies.
In cases, enterovirus infections happened more than 12 months before autoantibodies were first identified in samples. During this period, a mean 6.3 infections were diagnosed per case child vs 2.1 infections per control child per 10 follow-up years. These results suggest there is a lag between enterovirus infection and the development of islet autoantibodies.
This is an important study adding to the body of evidence relating to environmental factors contributing to T1D, however there is still a lot to be done. Not all people with T1D had evidence of enterovirus infections, indicating that that there are many other factors involved in the autoimmune process leading to T1D.
This study was only able to show an association, but not a causal effect of enterovirus in T1D. This study was undertaken in young people in Finland, and it is known that enterovirus infections differ between populations. Further studies in different population groups are needed to confirm if this association is seen in different areas, and different age groups.
These findings are important, as we need to understand what causes T1D before we can prevent it. Studies such as this continue to build a picture of the factors leading to T1D. If further studies continue to find associations between enteroviruses and the development of T1D, then there is hope that in future a vaccine could be developed to prevent enterovirus infection in people with T1D.
In Australia, the T1DCRN funded Environmental Determinants of Islet Autoimmunity (ENDIA) study is investigating factors during development that lead to islet autoimmunity and T1D. This is the only study of its kind worldwide investigating these factors before birth. ENDIA is following babies with a first degree relative with T1D from pregnancy through to early childhood, and measuring environmental factors such as bacteria and viruses, body growth and food exposures. This study will help to give more insight into what might be causing or protecting against T1D, including the possible role of viruses.
ENDIA is recruiting at major hospital across Australia, including a regional program for those who live in rural areas. Head to the ENDIA website to find out more or watch this video. To contact them, use the contact us form or call (08) 8161 8747.