Type 1 Diabetes: Causes and Risk Factors

What causes diabetes? Researchers have identified several genes associated with the development of type 1 diabetes. The prevailing belief about the etiology, or cause, of type 1 diabetes is that although someone may have a genetic predisposition for developing type 1 diabetes, it takes an environmental trigger or series of triggers (e.g., virus, toxin, drug) to set the autoimmune process in motion that destroys insulin-producing pancreatic beta cells and causes type 1 diabetes.

Risk factors for developing type 1 diabetes may include:

• Family history. A child that has a parent or sibling with type 1 diabetes has a 2 to 6% risk of developing the disease (the risk is higher if both a parent and sibling or an identical twin have type 1 diabetes). Although family history is important, 80% of people with type 1 diabetes do not have another relative with type 1 diabetes.
  
  
• Autoimmune diseases. The presence of other autoimmune disorders, such as thyroid disease and celiac disease, raises the risk of type 1 diabetes.
  
  
• Early cessation of breastfeeding and/or exposure to cow’s milk. Clinical research indicates that breastfeeding at least three months decreases the risk of type 1 diabetes.^1,2 Some studies have also found that exposure to cow’s milk or cow’s milk-based formula before one year of age may increase diabetes risk^3-6, although other studies have not borne out the link.
  
  
• Ethnicity. In America, Caucasians have a greater risk of type 1 diabetes than African Americans, Native Americans, Asian Americans, and Latinos. Worldwide, Finland and Sardinia have the highest incidence of type 1 diabetes.
  
  
• History of childhood viruses. Viruses that have been associated with type 1 diabetes as environmental triggers include coxsackie B, enteroviruses, adenovirus, rubella, cytomegalovirus, and Epstein-Barr virus.

Reviewed by Francine Kaufman, MD. 4/08