Finland has long had the highest rates of type 1 diabetes in the world. In this condition, previously known as juvenile diabetes, the immune system attacks the pancreas, which becomes incapable of producing insulin.
There have been hints that vitamin D deficiency may increase the risk of this disease. Because Finland is situated in the far north where sun exposure is not adequate for vitamin D production much of the year, the country started a campaign to fortify common foods with vitamin D in 2003.
A long-term study of Finnish children found that average blood levels of vitamin D around 2005 were significantly higher than those five years earlier. In the period from 1998 to 2002, nearly 70 percent of the youngsters were deficient in vitamin D, compared to only 37 percent from 2003 to 2006.
This change in vitamin D levels may be related to a significant decrease in the number of Finnish children developing type 1 diabetes after 2006.
For more information about vitamin D, we offer our Guide to Vitamin D Deficiency.