New JDRF-funded research published in the May issue of JAMA (The Journal of the American Medical Association) details evidence of a link between infections in early life and later development of type 1 diabetes (T1D).
It has long been thought that there could be a link between common viral infections and the development of T1D. Recent Australian research was the first to examine whether infection with a common virus, known as coxsackievirus B, could affect miRNAs in pancreatic islet cells, and so change the expression of genes associated with T1D. The study provided a possible mechanism for how infection with a common virus could trigger the development of T1D in people who are genetically at-risk.
May’s JAMA study, from German researcher Anette-Gabriele Ziegler and team, examined associations between T1D and infection types during the first two years of life and respiratory tract infections in the first six months. This is the first time research of this nature has been undertaken in a population-based dataset, which spanned 85% of all babies born in Bavaria during this period.
The study included nearly 300,000 babies born between 2005 and 2007, 720 of which went on to be diagnosed with T1D before 2015. At least one infection was reported during the first two years of life in 93 percent of all the children, and in 97 percent of children with T1D. T1D risk was also increased among children who experienced a respiratory tract infection between birth and six months of age. Thirty-nine percent of children who later developed T1D had contracted a respiratory infection before six months of age compared to 34% among those who didn’t develop T1D. Viral infections during this age period also showed an increased T1D risk (34% in T1D children vs 30% in non-T1D group).
The authors state, “It is unknown whether the association with early infections reflects increased exposure to virus or an impairment of the immune system response, perhaps due to genetic susceptibility”.
While these differences are statistically significant, they are small, which implies that there are other factors involved in the disease development.
What does this mean for prevention?
As the germs that cause these infections are airborne, it is obviously difficult to prevent transmission between individuals. As we know all too well, we can take all the recommended and available precautions and still come down with a cold or flu. As such, there’s no action that parents are required to — or can — take at this point in time.
For researchers, these findings further confirm that the first half-year of life is crucial for the development of the immune system and autoimmunity. This means we are a step closer to solving the mystery of how and why T1D develops, despite the interaction between genetic and environmental factors still remaining unclear.
Looking forward, the scientists want to understand whether there is actually a causal relationship and if so, which exact pathogens are involved and how they trigger the effect. This information could prove important in future vaccine development.