
June 7, 2002
Genetics and Heredity
Question from California, USA:
There is a high incidence of adult onset diabetes (parents and grandparents) in my family, so we have a few questions regarding children:
What is the incidence of diabetes developing in children?
Is the incidence of juvenile diabetes increasing?
I realize heredity plays a part in our predisposition to this disease, but what other factors contribute?
Can it be prevented?
Answer:
Your question is a little more complicated than perhaps you realised because a small proportion of adults who develop diabetes have a form of type�1A (autoimmune) diabetes which is called Late-onset Autoimmune Diabetes of Adulthood (LADA). Be that as it may, I am going to assume that your questions relate to autoimmune diabetes in children and not to the incidence of type 2 diabetes in children which is increasing with the increased use of high calorie, high fat junk foods combined with a more sedentary life style.
The incidence of type 1A diabetes varies substantially between countries. In Finland, it is now around 40/100,000 population below the age of 18, in the USA and Northern Europe, it is a little less than half this, and amongst the Chinese significantly lower again.
The incidence of this form of diabetes does appear to increasing slowly all over the world, but the reason for this is not yet understood.
Inherited factors, especially the HLA pattern of cell surface proteins plays a major role in determining susceptibility, but environmental factors are required to trigger autoimmunity. Again, these are not known although a case has been made for early exposure to cow’s milk and for enterovirus infections having a role.
A great deal of research is being devoted to the prevention of autoimmune diabetes in those who are genetically susceptible, but so far it has not been successful. However, a study in New Zealand children has shown that nicotinamide can defer insulin dependence for up to eight years in susceptible subjects, and the results of a similar study in Europe called ENDIT will soon be available. There is also hope that with our greatly increased understanding of the autoimmune process ways will be found to modify this response without recourse to lifetime immunosuppression.
Type�2 diabetes at any age can be significantly averted by strict weight control and a vigorous exercise program — easy to talk about and very hard to sustain. [Ed. See Diabetes Prevention Program for information about a study about preventing type 2 diabetes.]
DOB