Getting enough vitamin D during infancy and childhood is associated with a reduced risk of islet autoimmunity among children at increased genetic risk for type 1 diabetes, according to a study published in the journal Diabetes.
The study’s lead author, Dr. Jill Norris, of the Colorado School of Public Health department of epidemiology, and her co-authors examined the association between vitamin D levels in the blood and islet autoimmunity. Islet autoimmunity, detected by antibodies that appear when the immune system attacks the islet cells in the pancreas that produce insulin, is a precursor to type 1 diabetes.
“For several years there has been controversy among scientists about whether vitamin D lowers the risk of developing of islet autoimmunity and type 1 diabetes,” said Dr. Norris.
Type 1 diabetes is a chronic autoimmune disease that is increasing by 3 – 5 percent annually worldwide. The disease is now the most common metabolic disorder in children under age 10. In younger children, the number of new cases is particularly high. And the risks seem to be greater at higher latitudes, further north from the equator.
Vitamin D represents a candidate protective factor for type 1 diabetes as it regulates the immune system and autoimmunity. Moreover, vitamin D status varies by latitude. But associations between vitamin D levels and islet autoimmunity have been inconsistent. This may be due to different study designs, population variation in vitamin D levels, or a failure to account for the combined effect of exposure and underlying genetic variation in the vitamin D pathway.