Genetic factors cannot fully explain the development of diabetes. Over the past 30 years, a major increase in the incidence of type 1 diabetes has been reported in certain European countries, and the incidence has nearly tripled in the northeastern U.S. If genetic factors were the only cause of type 1 diabetes, such an increase in cases would take at least 400 years.
Viruses
Some researchers believe one or more viral infections may trigger the disease in genetically susceptible individuals. Researchers suggest the following scenario:
- An infection introduces a viral protein that resembles a beta-cell protein.
- T cells and antibodies are tricked by this resemblance into attacking the beta protein as well as the virus.
Among the viruses under scrutiny are enteric viruses, which attack the intestinal tract. Coxsackieviruses are an enteric virus of particular interest. (One study has suggested that respiratory infection in a child's first year, and not later, may be protective against diabetes, perhaps by priming the immune response so that it is better able to respond later on to other organisms.)
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