Type 1 diabetes increased among young people during the pandemic, reveals research

During the Covid-19 pandemic, there was an unexpected increase in the number of cases of type 1 diabetes in Sweden, particularly among children under five and young adult men. The infection accelerated the onset of diabetes among children between the ages of five and nine.

The researchers looked at data from a 17-year period on the incidence of type 1 diabetes among all people under the age of 30 in Sweden. In addition, they compared the risk of developing diabetes among 720,000 individuals with positive Covid-19 tests against a control group of 3.5 million people.

“Through Sweden’s health and population registers, we have been able to follow people from 2007 to 2023 and can see that more individuals developed type 1 diabetes during the pandemic than previously. This applied particularly to children under five and young adult men,” says Dominik Dietler, a researcher at Lund University.

The number of diabetes cases increased by 12 per cent in 2021 and 9 per cent in 2022 compared with previous years. In 2023 the number of cases was back to a normal level. Despite this, the researchers cannot distinguish a clear connection between Covid-19 infection and diabetes, except for children between five and nine years. They had an increased risk of type 1 diabetes about one month after a Covid-19 infection even though their total risk did not increase.

“Regardless of previous infections, type 1 diabetes often debuts at this age. Infections do not seem to cause type 1 diabetes as such, but may accelerate or trigger the onset among individuals who are already on the way to developing the disease.”

More studies are needed to understand what lies behind the increase during the pandemic, comments Dominik Dietler, as there could be other factors such as lifestyle changes that affect the onset. Other studies have shown, for example, an increase in BMI among children and a reduction in physical activity among teenagers. Stress and changes in diet may also be contributing factors that trigger diabetes.

“However, it’s clear that the Covid-19 vaccine can be ruled out as a cause of the increase in diabetes cases. The recommendation for the age group where we saw the strongest increase was not to get vaccinated. In addition, other studies on adults have shown that vaccination reduces the risk of developing type 1 diabetes after a Covid infection.”

A corresponding increase in the number of diabetes cases has also been noted in other countries such as Denmark and the USA. However, Dominik Dietler is slightly surprised by the results, as Sweden had relatively mild restrictions compared with other countries. In a future health crisis it could therefore perhaps be necessary to implement additional initiatives to maintain a healthy lifestyle.

“In a follow-up study we are now looking more closely at other factors that can affect the risk of developing type 1 diabetes during a public health crisis. Among other things, this concerns factors that affect how easy or hard it is to live healthily, such as economic conditions, housing situation, access to green spaces and the option of working from home.”

Reference:

Dietler, D., Björk, J., Palmkvist, E. et al. Trends in type 1 diabetes incidence between 2007 and 2023 and their association with SARS-CoV-2 infection in a population-based matched cohort study among individuals under 30 years old in Sweden. Diabetologia (2025). https://doi.org/10.1007/s00125-025-06540-1