Diabetes Causes   Type 1 diabetes: Type 1 diabetes is believed to be an autoimmune disease. The body's immune system attacks the cells in the pancreas that produce insulin. A predisposition to develop type 1 diabetes may run in families, but genetic causes (a postitive family history) is much more common for type 2 diabetes. Environmental factors, including common unavoidable viral infections, may also contribute. Type 1 diabetes is most common in people of non-Hispanic, Northern European descent (especially Finland and Sardinia), followed by African Americans, and Hispanic Americans. It is relatively rare in those of Asian descent. Type 1 diabetes is slightly more common in men than in women. Type 2 diabetes: Type 2 diabetes has strong genetic links, meaning that type 2 diabetes tends to run in families. Several genes have been identified and more are under study which may relate to the causes of type 2 diabetes. Risk factors for developing type 2 diabetes include the following: High blood pressure High blood triglyceride (fat) levels Gestational diabetes or giving birth to a baby weighing more than 9 pounds High-fat diet High alcohol intake Sedentary lifestyle Obesity or being overweight Ethnicity, particularly when a close relative had type 2 diabetes or gestational diabetes: certain groups, such as African Americans, Native Americans, Hispanic Americans, and Japanese Americans, have a greater risk of developing type 2 diabetes than non-Hispanic whites. Aging: Increasing age is a significant risk factor for type 2 diabetes. Risk begins to rise significantly at about age 45 years, and rises considerably after age 65 years.