Causes and risk factors

Type 1 diabetes is caused by the destruction of the cells that are responsible for making insulin; however, it is not known how or why these cells get destroyed. Experts have suggested that the destruction process may be triggered by a viral infection.

There are a number of different risk factors which may contribute to type 2 diabetes; these include:

  • Age: people aged over 40 and those who have Black or Asian heritage and are aged over 25 are more at risk of developing type 2 diabetes
  • Being overweight: people who are overweight have a much higher risk of developing diabetes than people who are a healthy weight. Having a large waist can also increase the risk (women who have a waist measurement of over 31.5 inches, Asian men that have a measurement of over 35 inches and Black and White men that have a measurement of over 37 inches have a higher risk of diabetes)
  • Family history: having a relative with type 2 diabetes increases your risk of developing diabetes; the chances are higher if the relative is a close relative (i.e. a parent or sibling)
  • Hypertension (high blood pressure)
  • Women that had gestational diabetes
  • People with impaired glucose tolerance or impaired fasting glycaemia (both these conditions cause glucose levels in the blood to be higher than normal)
  • Women that have been diagnosed with polycystic ovary syndrome and are overweight
  • Other health conditions, including heart disease, strokes and those that affect your circulatory system

Guide to Diabetes


Types of diabetes

Causes and risk factors

Living with diabetes

Preventing diabetes

Recognising the symptoms of diabetes

Treating diabetes