Environmental factors that affect the health of the intestinal microbiome, such as the widespread use of antibiotics, may underlie some of the marked differences in the prevalence of type 1 diabetes seen between neighboring populations, say Finnish researchers.
Finnish children have a much higher rate of type 1 diabetes than Russian children in the next-door region of Karelia, and a series of studies by a PhD student and colleagues indicate that this variance could be due, at least in part, to differences in the gut microbiome.
Tommi Vatanen, the PhD student from the department of computer science, Aalto University, Helsinki, Finland, and others looked at microbiome changes just before the onset of type 1 diabetes, and they also investigated the impact of antibiotic treatment on the microbiome.
Their findings have been disseminated in four previously published papers involving almost 300 infants in Finland, Estonia, and Russian Karelia, alongside data on more than 1000 Dutch adults. Now the work has been combined for the first time and published online by Aalto University on March 24 for Vatanen’s doctoral thesis.
“The composition of the microflora in children’s intestines was extremely different in Russian and Finnish infants,” Mr Vatanen explains in an Aalto University press release.
“Finnish subjects began to develop autoantibodies to type 1 diabetes, meaning the disease’s early symptoms. Russian children did not develop the antibodies at all.”
For Vatanen, the findings underline the importance of the microbiome in the first years of immune-system development. He said: “In a way, intestinal microbes teach the body’s immune system. If something goes wrong this early on, autoimmune diseases may become more common.”
Striking Differences From Early in Life Between Finland, Estonia, and Karelia
Speaking to Medscape Medical News, Mr Vatanen said that, from very early on when they started looking at the three populations in Finland, Estonia, and Russian Karelia, they saw “a striking difference there, so then the goal was basically to find some meaningful details in those differences.”
They began the project 4 years ago, at the beginning of his PhD studies. “Back then, very little was known about the infant microbiota,” he explained. “This whole field has developed so quickly that we basically set out the first study to describe the dynamic nature of the developing microbiome.”
The inspiration came from previous work showing that, despite sharing a geographical region and a similar genetic background, there is a steep gradient of autoimmune diseases and allergies between Finland and Russian Karelia, with, for example, the incidence of type 1 diabetes being five- to sixfold higher and the incidence of allergic diseases two- to…