Quite often when a person with newly detected Diabetes is asked whether he has a parent or other family member suffering from Diabetes, the answer invariably put forward is "Doc, I do have a brother who is a diabetic but he is settled abroad and we have not lived together for the last 20 years."
The point to be clarified is that family history of diabetes is not obtained to find out whether diabetes has been communicated by another family member because diabetes is not an infection or communicable disease which can be transmitted from one individual to another. On the other hand, family history of diabetes is obtained because Type 2 Diabetes Mellitus tends to run in families with an inherent or genetic preponderance which makes individuals with a positive family history more prone to develop diabetes.
In the case of a positive family history also, there is however another important aspect often less understood. Many a time, while giving positive family history of diabetes, a newly detected Diabetic hastens to add, "Doc, my father also had diabetes but he got it only at the age of 60. So, how is it that I have got it at the age of 40 itself?" The answer is that the father's lifestyle, eating habits, level of physical activity, level of stress etc were different from those of the son. And there lies the catch!
Family history of Diabetes, particularly in parents or siblings, does increase the risk to develop it. But …. maintainence of optimum body weight, judicious dietary habits, adequate level of physical activity, freedom from stress and overall discipline in life can help an individual to avoid or delay onset of Diabetes despite a positive family history.
Younger Age of Onset
Diabetics with a diabetic parent are found to be both younger and also younger at the time of diagnosis. Furthermore, the observation is that, on an average, diabetes becomes evident about 6 years earlier in presence of parental Diabetes than in case of Diabetics who have no diabetic relative. Some scholars believe that age of diabetes onset could be genetically determined.
Various studies, however, donot point out any significant difference in the prevalence of chronic diabetic complications in diabetics with a family history of diabetes visavis diabetics with no family history. This indicates that individually acquired factors could be more relevant than family history in determining a diabetic's vulnerability to develop diabetic complications.
Interestingly, young adult offsprings of diabetic parents are often found to be significantly more obese than those of non-diabetic parents.
In a nutshell, as far as the influence of family history of Type 2 Diabetes Mellitus is concerned, the genetic component seems relevant from an early age whereas environmental factors seem to become more relevant at later stages.