Type 1 diabetes, previously called juvenile diabetes, is a form of diabetes characterized by decreased insulin production by the pancreas. Insulin is essential to help cells absorb glucose from the bloodstream to use for energy. Only 5 to 10 percent of diabetics have Type I, the American Diabetes Association (ADA) states. Type 1 diabetes usually develops in people under 30 years of age, according to the Merck Manual, and has different risk factors and causes than Type 2 diabetes, the more common type that normally occurs in adults and is associated with obesity.
Autoimmune Activation
Type 1 diabetes is caused by an autoimmune reaction that destroys the insulin-producing cells in the pancreas. Why the autoimmune response is initially triggered is a question that does not yet have a definitive answer. Environmental and genetic factors, along with viruses, may all need to come together in a certain way for a person to develop the antibodies that attack the beta cells in the pancreas and destroy them completely within 5 to 10 years, the University of Maryland Medical Center states.
Genetics
Unlike Type 2 diabetes, which more commonly found in blacks and Hispanics, Type 1 diabetes more often affects Caucasians. The ADA claims that both parents must pass on a gene for diabetes for a child to inherit it. Most people with Type 1 diabetes don't have a relative with the disease, UMMC states, and even with identical twins, who have the same genetic makeup, the chances of one twin having the disease if the other one does is only 33 percent. A child is more likely to develop Type 1 diabetes if her father has it than if her mother has it, but the chances of having diabetes if a first degree relative has it is only 10 percent, UMMC reports. Susceptible genes have been identified in more than 90 percent of people with Type 1 diabetes, the Merck Manual reports.
Viruses
Certain viruses seem to activate Type 1 diabetes either by destroying beta cells or by activating immune responses. Rubella, cytomegalovirus, Coxsackie virus, Epstein-Barr and retroviruses have all been implicated in Type 1 diabetes, Merck claims.
Environmental Factors
According to the ADA, people who live in cold climates are more likely to develop Type 1 diabetes. Early diet may also affect Type 1 diabetes development; people who were breastfed as infants and who started solid food less likely to have Type 1 diabetes. Babies who started solid foods before age 4 months or after 7 months, those whose water supply contains high nitrogen levels and those with low vitamin D levels were more likely to develop the disease, Merck states.
Idiopathic
Rarely, a form a Type 1 diabetes develops, especially in non-white populations, which is not related to autoimmune destruction of the beta cells. This type of disease is called idiopathic, meaning that there's no known cause.
