Finland has the world’s highest rate of type 1 diabetes, yet researchers have not established what makes the disease so common in the country. Around 50,000 people in Finland live with the condition, and approximately 1,000 new cases are diagnosed every year.
Type 1 diabetes is an autoimmune disease in which the body’s immune system attacks the insulin-producing cells in the pancreas. As these cells are destroyed, the body loses its ability to produce insulin, a hormone needed to regulate blood sugar levels. People with the condition must therefore rely on insulin treatment throughout their lives.
Despite decades of research, the reasons behind Finland’s unusually high rates remain unclear. Other Nordic countries also report high levels of type 1 diabetes, leading scientists to investigate whether climate, genetics, lifestyle or environmental conditions could help explain the pattern.
Lena Thorn, a diabetes doctor and associate professor of general medicine at the University of Helsinki, is leading a research project focused on the disease. Speaking on Yle’s programme “Lite klokare”, which translates roughly as “A Little Wiser”, she answered questions from listeners about type 1 diabetes and the possible reasons for its high prevalence in Finland.
One theory concerns the country’s climate and limited sunlight during parts of the year. Researchers have questioned whether low vitamin D levels could contribute to the development of the disease. However, Thorn said there is currently no clear evidence establishing a link.
“Among other things, it is suspected that the dark climate and vitamin D deficiency could play a part, but there is no clear evidence for this,” she said.
Comparisons between Finland and neighbouring Russia offer another important research clue. Although people on both sides of the border share similar genetic backgrounds, the risk of developing type 1 diabetes is considerably higher in Finland. This difference has strengthened the argument that environmental factors may contribute to the disease.
The experience of people who move to Finland provides further evidence for this possibility. According to Thorn, migrants who settle in the country eventually face a similar risk of developing type 1 diabetes to that of people born in Finland. This suggests that factors associated with the Finnish environment may influence the likelihood of developing the condition, although researchers have yet to identify the specific causes.
While the reasons behind Finland’s high rate remain uncertain, the treatment of type 1 diabetes has changed considerably over the past three decades. Patients previously faced stricter treatment routines, including hospital stays and carefully planned meals. Managing the condition often required significant adjustments to everyday life.
Thorn said the approach to treatment has shifted towards meeting individual needs. Rather than expecting patients to organise their lives around a fixed treatment routine, healthcare professionals can now adapt treatment to suit each person’s circumstances.
Insulin technology has played an important role in this change. Many patients, particularly children, are now offered semi-automated insulin pumps when they are diagnosed. These devices help regulate insulin delivery and reduce some of the demands of managing the condition.
Fast-acting insulin has also given patients greater flexibility around meals, making it easier to manage blood sugar levels without following the same strict eating schedules that were once common. However, access to insulin pumps has not always been equal across Finland, with availability varying between regions.
For researchers, the central question remains unanswered: why does Finland have a higher rate of type 1 diabetes than any other country? The differences between Finland and neighbouring Russia, as well as the experience of migrants, continue to provide important clues, but the precise environmental factors responsible have not yet been established.
