March 21 (HealthDay News) -- Children who take vitamin D supplements may be less likely to develop type 1 diabetes later in life, according to researchers who analyzed the findings of five previously published studies.

The researchers found that children who were given additional vitamin D were about 30 percent less likely to develop type 1 diabetes than children who didn't receive vitamin D supplements. The evidence also indicated that the higher and more regular the dose of vitamin D, the lower the risk of developing diabetes.

The findings were published online in the journal Archives of Disease in Childhood.

Type 1 diabetes, an autoimmune disorder, develops when insulin-producing cells in the pancreas are destroyed by the body's immune system, a process that begins in early infancy, according to background information in the review study.

The incidence of type 1 diabetes is increasing by about 3 percent a year, and it's estimated that new cases of the disease will have increased 40 percent between 2000 and 2010. People of European descent are most likely to have type 1 diabetes, which affects about two million Europeans and North Americans.

There's evidence that levels of vitamin D and exposure to sunlight, which prompts the body to make vitamin D, influence the risk of developing some types of autoimmune disorders.

The review authors noted that global rates of type 1 diabetes vary greatly, according to latitude and levels of sunlight. For example, a child in Finland is 400 times more likely than a child in Venezuela to develop type 1 diabetes.

The fact that pancreatic beta cells and immune cells carry receptors for the active form of vitamin D provide further proof of the link between vitamin D and type 1 diabetes, the review authors said.

SOURCE: JAMA/Archives journals, news release, March 2008