The Hygiene Hypothesis: An Explanation for the Increased Frequency of Insulin-Dependent Diabetes

The steadily increasing frequency of insulin-dependent diabetes in several countries is best explained today by the decline of infections. Epidemiologic and animal data support this conclusion, which, however, requires confirmation by intervention trials in man. The mechanisms of the protective effect of infections on diabetes onset are diverse including competition for homeostatic factors and stimulation of regulatory T cells and of Toll-like receptors. These considerations might have interesting therapeutic applications for the prevention of the disease.