Sweden has, after Finland, the highest reported incidence of type 1 diabetes in the world. The disease, which is due to the immune system incorrectly attacking the insulin-producing cells, is chronic and mainly affects children and young people.
Now, researchers from the University of Gothenburg have investigated whether there is a connection between people who have been affected by type 1 diabetes and where they lived during their first years of life. They used the National Diabetes Register to obtain information about people who were diagnosed with type 1 diabetes between 2005 and 2022, a total of just over 21,800 people
In the comparison, they saw that there were areas with higher and lower risk. A total of four high-risk areas were identified, all of which are located in rural areas, mainly in the northern parts of Sweden.
Low risk in Växjö
The relative risk of developing type 1 diabetes was between 30 and 80 percent higher compared to the average. No high-risk clusters were found in the major cities.
In major cities such as Stockholm, Malmö and Gothenburg, the risk was between 20 and 50 percent lower of getting the disease compared to the average.
It was surprising that the pattern was so clear and above all linked to where you live in the very first years of life, says Soffia Gudbjörnsdóttir, professor at the University of Gothenburg and one of the researchers behind the study.
In rural areas in northern Sweden, the risk was highest. The lowest risk was found in cities in southern Sweden such as Växjö, Norrköping and Halmstad.
Maybe infections
The researchers do not know why it looks like this, but among other things, they suggest that one possible explanation may be that viral infections are more common among children in larger cities. This could have a protective effect against autoimmune diseases, while children in rural areas may be exposed to more pesticides.
But we do not know why some develop type 1 diabetes, but now we have a basis that we can move on with, says Soffia Gudbjörnsdóttir.
The results will be presented at a European diabetes conference in September and have not yet been published in any scientific journal.
