The third causative factor is discussed here
(3) The Environmental or Modifiable Factors:
Susceptibility to diabetes can be unmasked by a number of environmental factors acting on genetically susceptible individuals. They include:
(i) Obesity: Obesity is a risk factor for NIDDM and the risk is related to both the duration and degree of obesity. Obesity reduces the number of insulin receptors on target cell, but in most cases, it produces resistance to action of insulin, which means insulin can not do its job. But, many obese subjects are not diabetic. Thus obesity by itself is inadequate to account for all or even most of the cases of NIDDM; physical inactivity and /or deficiencies of specific nutrients may also be involved. Obesity appears to play no role in IDDM pathogenesis.
(ii) Sedentary life style: Sedentary life style is an important risk factor for the development of NIDDM. Lack of exercise may alter the interaction between insulin and its receptors and subsequently lead to NIDDM.
(iii) Diet: Studies indicated that the diet of diabetics did not differ in any marked way from that of non-diabetics except in quantity. There is no sound evidence that diabetes is specifically associated with high intake of any of the major nutrients. Excessive intake of alcohol can increase the risk of diabetes by damaging the pancreas and liver and by promoting obesity.
(iv) Malnutrition: Malnutrition (protein energy malnutrition or PEM) in early infancy and childhood may result in partial failure of beta-cell function. Damage to beta cells explains the associated impaired carbohydrate tolerance in kwashiorkor (malnutrition due to severe protein deficiency).
(v) Viral infections: Among the viruses that have been implicated are rubella, mumps, and human coxsackie virus B4. Viral infections may trigger, in immunogenetically susceptible people a sequence of events resulting in beta-cell destruction.
(vi) Chemical agents: A number of chemical agents are known to be toxic to beta cells, e.g., alloxan, streptozotocin, the rodenticide valcor, etc. A high intake of cyanide producing foods (e.g., cassava and certain beans) may also have toxic effects on beta-cells.
(vii) Stress: Surgery, trauma, and other stress situations (internal or external) may “bring out” the disease.
(viii) Other factors: High and low rates of diabetes have been linked to a number of social factors such as occupation, marital status, religion, economic status, education, urbanization and changes in life style which are elements of what is broadly known as social class. One of the most important epidemiological features of diabetes is that it is now common in the lower social classes whereas 50 years ago, the gradient was the reverse. One reason could be rapid changes in life style in lower classes.
Tags: Kwashiorkor, Malnutrition, obesity, Stress
