ENVIRONMENTAL FACTORS IN THE
ETIOLOGY OF TYPE 1
DIABETES
Akerblom
HK
Hospital
for Children and Adolescents, University of Helsinki, Helsinki, Finland
The current concept of the etiology and
pathogenesis of type 1 diabetes in children is as follows: environmental
factors, either alone or in combination trigger in a genetically
susceptible individual an autoimmune process in the pancreas which leads to
the destruction of the insulin secreting betacells. A clear increase in the
incidence of childhood type 1 diabetes has been observed in many countries
over the last decades. This speaks in favor of an essential role of
environmental factors. The main candidates among them are viral infections,
some dietary factors, toxins and stressful life events. In addition, two
factors are likely important in industrialized countries: increased growth
and a tendency to older maternal age at delivery. The Accelerator
Hypothesis”, recently proposed by Wilkin (Diabetologia 2001:44:914-922)
holds that insulin resistance, resulting from a combination of obesity and
physical inactivity, is a central environmental factor in the etiology of
type 1 diabetes.
As a genetic predisposition
is needed for the development of type 1 diabetes, and it can be of variable
strength (like also the existence of genetic protection in some other
individuals), the final outcome in the etiopathogenetic process depends on
the interaction between this genetic component and the aggressiveness of
the environmental factor(s). With reference to prediction and prevention
studies, it is crucial to learn more about the interaction of genetic and
environmental factors in this disease (Akerblom H.K. and Knip M.
Diab/Metab.Rev. 1998;14:31-67).