Healthnotes Newswire (December 28, 2006)—Vitamin D deficiency may be an underlying cause of type 1 diabetes, according to Swedish researchers. Blood levels of vitamin D, which are primarily obtained by sun exposure, were low in young adults recently diagnosed with the disease.

“Several studies suggest that vitamin D supplementation in early childhood decreases the risk of developing type 1 diabetes,” wrote Bengt Littorin of the Department of Clinical Sciences, University of Lund, in Malmö, Sweden. Dr. Littorin and colleagues suggest that there is “an immunological mechanism behind the association between vitamin D and type 1 diabetes.” They conducted research designed to demonstrate whether or not low vitamin D in the circulation promotes the development of type 1 diabetes.

In addition to its better-known functions in supporting bone health, vitamin D also has effects on immune function. Researchers believe that insufficient vitamin D may trigger the immune system to attack its own insulin-producing cells. In previous studies, women who got low amounts of vitamin D during pregnancy were more likely to have children with antibodies against the insulin-producing cells in the pancreas, called islet cells. Antibodies against islet cells initiate a process that leads to destruction of these cells, and the resulting lack of insulin impairs the body’s ability to handle glucose, leading to type 1 diabetes.

Littorin and colleagues recruited volunteers, both healthy and with type 1 diabetes, for the study. The people with diabetes, ages 15 to 34, all had confirmed antibodies against islet cells. Blood levels of vitamin D were measured in samples taken from all participants at the start of the study, and eight years later. The results compared those with diabetes to those of the same age and gender who did not have the disease.

Blood levels of vitamin D were found to be significantly lower in the people with diabetes. “It could be that the initiation of type 1 diabetes is related to low vitamin D concentrations,” Dr. Littorin concluded. With more studies, researchers may find that adequate sun exposure and vitamin D supplementation contribute to the prevention of this serious autoimmune disease.

(Diabetologia 2006;49:2847–52)