Type 1 diabetes occurs when the immune system mistakenly attacks and kills the beta cells of the pancreas. No, or very little, insulin is released into the body. As a result, sugar builds up in the blood instead of being used as energy. About five to 10 per cent of people with diabetes have type 1 diabetes. Type 1 diabetes generally develops in childhood or adolescence, but can develop in adulthood. - See more at: http://www.diabetes.ca/about-diabetes/types-of-diabetes#sthash.btyKmWr0.dpuf