Health
Type 1 diabetes results from the immune system destruction of pancreatic cells which produce the insulin.
Type 1 diabetes is most common among people of European descent.
It is becoming increasingly common, and it is estimated that the number of new cases will rise by 40% between 2000 and 2010.
The Manchester team pooled data from five studies examining the effect of vitamin D supplementation.
Not only did the use of supplements appear to reduce the risk, the effect was dose dependent - the higher and more regular the dose, the lower the likelihood of developing the disease.
Previous research has found that people newly diagnosed with type 1 diabetes have lower concentrations of vitamin D than those without the condition.
Studies have also found that type 1 diabetes is more common in countries where exposure to sunlight - which enables the body to manufacture vitamin D - is lower.
For instance, a child in Finland was 400 times more likely to develop the disease than a child in Venezuela.
Separate research has linked low levels of vitamin D and sunlight to other autoimmune disorders, including multiple sclerosis and rheumatoid arthritis.
Further evidence of vitamin D's role comes from the fact that pancreatic beta cells and immune cells carry receptors or docking bays for the active forms of the vitamin.
It is thought that vitamin D helps to keep the immune system healthy, and may protect cells from damage caused by chemicals which control inflammation.
Governnment experts recommend vitamin D supplementation for at least the first two years of a child's life, although the Chief Medical Officer for England has suggested supplements for the first five years is a good idea.