The exact cause of type 2 diabetes is not fully understood. It seems to be the result of excess body weight and physical inactivity. Your genetic make-up can also make you more likely to develop it.
There are several factors that make developing the condition more likely.
Type 2 diabetes is more common in those who:
- are South Asian, African-Caribbean or Middle Eastern
- are overweight or obese
- are over 40
- have a close relative with type 2 diabetes
- have a waist measuring more than 31.5 inches (80cm) if you are a woman or more than 37 inches (94cm) if you are a man
- have had impaired glucose tolerance or impaired fasting glycaemia - sometimes called 'pre-diabetes'
- have had gestational diabetes (diabetes in pregnancy).
Type 2 diabetes can occur for two reasons:
- your body may not make enough insulin to keep glucose levels in the blood within a normal range
- your body may not react to insulin in the right way, which is called insulin resistance.
See also What is type 2 diabetes?