Impaired fasting glucose

Impaired fasting glucose is often without any signs or symptoms, other than higher than normal glucose levels being detected in an individual's fasting blood sample. There may be signs and symptoms associated with elevated blood glucose, though these are likely to be minor, with significant symptoms suggestive of complete progression to type 2 diabetes. Such symptoms include:[4]

• Increased thirst
• Increased urination, especially waking up in the night to urinate
• Tiredness and fatigue
• Blurred vision
• Slow healing of wounds
• Altered sensation, such as numbness or tingling, particularly of the hands and feet
• Recurrent, and difficult to clear infections, particularly of the urinary tract

As impaired fasting glucose is considered a precursor condition for type 2 diabetes, it shares the same environmental and genetic risk factors.

Different organisations use slightly differing levels before classifying a person's fasting blood glucose as "impaired", with the American Diabetes Association using a lower cutoff in its criteria than the World Health Organization. The upper limits remain the same, as fasting levels above this are almost universally accepted as indicative of full diabetes:

• WHO criteria: fasting plasma glucose level from 6.1 mmol/L (110 mg/dL) to 6.9 mmol/L (125 mg/dL).[5][6][7]
• ADA criteria: fasting plasma glucose level from 5.6 mmol/L (100 mg/dL) to 6.9 mmol/L (125 mg/dL).

The guidelines for preventing impaired fasting glucose are the same as those given for preventing type 2 diabetes in general. If these are adhered to, the progression to clinical diabetes can be slowed or halted. In some cases, a complete reversal of IFG can be achieved. Certain risk factors, such as being of Afro-Caribbean or South Asian ethnicity, as well as increasing age, are unavoidable, and such individuals may be advised to follow these guidelines, as well as monitor their blood glucose levels, more closely.