What Causes Diabetes?

Answer by Alexander van Hattem:

Which diabetes do you mean, exactly?

“Diabetes” comes originally from ancient Greek and means “Excessive discharge of urine”.  There are many diseases that can cause this, and off the top of my head, I can think of diabetes mellitus type 1, diabetes mellitus type 2 and diabetes insipidus.  I know an endocrinologist could tell you of some others, but those are the most common ones.  They are different disorders with different underlying causes.

Diabetes Mellitus Type 1 describes a syndrome in which people lose the insulin producing cells that exist in the pancreas.  It can happen when the body attacks its own cells, in which case the cause is described as autoimmune, or it can happen for reasons not yet ascertained, in which case it is referred to as idiopathic.  People with this disease cannot survive without an external source of insulin, mostly given by injection.

This kind of diabetes is completely unrelated to lifestyle, and usually occurs in children (it used to be called “juvenile diabetes”).  It is generally considered that people are predisposed to it by the presence of certain genes, but the disease only manifests after an environmental trigger like a viral infection.

Diabetes Mellitus Type 2 is probably what most people mean when they say diabetes.  Here, the patient still produces insulin, but either not enough, or their other cells are resistant to the action of insulin, so many of the symptoms are the same as if they had no insulin.

Here, there is no single cause, but rather a number of factors each of which increases the risk of developing of the disease.  Genes do play a role.  Excess body fat is associated with most cases.  7% of cases can apparently be attributed to lack of exercise.  Dietary intake is also a contributing factor, especially saturated fats, sugary drinks, and white rice.

Diabetes insipidus has nothing to do with sugar or insulin.  It is caused by insufficient secretion of antidiuretic hormone (ADH) in the pituitary gland, or poor sensitivity to that hormone in the kidneys.  It can have a huge range of underlying causes, including autoimmune disease, vascular problems, infection, head injuries, tumours, or gestational.  Many cases are described as idiopathic, meaning no underlying cause is ever found.

What causes diabetes?