Endocrine Abstracts

The incidence of type 1 diabetes (T1D) has increased markedly after World War II among children and adolescents, and in parallel the mean age at diagnosis has decreased. These trends support a critical role of exogenous factors in the development of T1D, since genetic factors alone can hardly explain the rapid increase. The hygiene hypothesis postulating a relationship between allergic diseases and a childhood environment characterized by a decreased pathogen exposure has recently been expanded to explain the rising incidence of autoimmune diseases such as T1D. It is conceivable that a decreased microbial load in early life may have a major impact on the programming of the immune system. Enterovirus infections have been implicated as potential triggers of the disease process leading to T1D. The frequency of enterovirus infections has, however, lately decreased among the general population in developed countries at the same time as the T1D incidence has increased. This seeming contradiction can be explained by the so called polio hypothesis, according to which the decreasing infection rate in the general population results in a situation where infants have an impaired protection against acute enterovirus infections early in life. This may then result in more invasive enterovirus infections, some of which might lead to the induction of the diabetic disease process as a complication. Bovine insulin have been proposed to function as a driving exogenous antigen in T1D. One can speculate that the increasing processing of milk products may have some impact on the immunogenicity of bovine insulin in commercial milk products. Children grow linearly and gain weight faster now than some decades ago. Rapid growth and weight gain induces beta-cell stress and could thereby lead to an earlier presentation of clinical T1D and also an increasing incidence by expanding the proportion of susceptible individuals progressing to overt disease.

Declaration of interest: The author declares that there is a conflict of interest.

Funding: This work was supported, however funding details are unavailable.