Impaired fasting glucose, more commonly known as pre-diabetes refers to a condition in which
the fasting blood glucose level is consistently elevated above what is considered normal levels;
however, it is not high enough to be diagnosed as diabetes mellitus. This pre-diabetic state
is associated with insulin resistance and increased risk of cardiovascular pathology,
although of lesser risk than impaired glucose tolerance. IFG can progress to type 2 diabetes
mellitus if lifestyle changes are not made. There is a 50% risk over 10 years of progressing
to overt diabetes. A recent study cited the average time for progression as less than
three years. Fasting blood glucose levels are in a continuum
within a given population, with higher fasting glucose levels corresponding to a higher risk
for complications caused by the high glucose levels. Impaired fasting glucose is defined
as a fasting glucose that is higher than the upper limit of normal, but not high enough
to be classified as diabetes mellitus. Some patients with impaired fasting glucose can
also be diagnosed with impaired glucose tolerance, but many have normal responses to a glucose
tolerance test.
Signs and Symptoms The World Health Organization criteria for
impaired fasting glucose differ from the American Diabetes Association criteria, because the
normal range of glucose is defined differently. The WHO has defined the upper limit of normal
at under 110 mg/dL. However, fasting glucose levels 100 mg/dL and higher have been shown
to increase complication rates significantly, and the ADA has lowered the upper limit of
normal accordingly, to a fasting glucose under 100 mg/dL.
WHO criteria: fasting plasma glucose level from 6.1 mmol/l to 6.9 mmol/l.
ADA criteria: fasting plasma glucose level from 5.6 mmol/L to 6.9 mmol/L.
Risk factors IFG is a risk factor for mortality due to
the serious complications of type 2 diabetes mellitus. Diabetes is a multi-factor disease
and it can affect many areas of the body. The depositions of plaque in the arteries
known as atherosclerosis are a potential risk that is elevated in diabetic individuals.
This may lead to heart attack or stroke. Blindness is another concern associated with type 2
diabetes. It is caused by microvascular disease in which high blood glucose levels damage
blood vessels in the retina by the formation of scar tissue or hemorrhage. Not only do
these high levels cause vision loss, they may also cause sensory nerve damage. This
presents as tingling, numbness or pain and in the most severe cases requires amputation.
When these elevated levels of blood glucose are chronic there is a potential that irreversible
kidney damage can occur. It is important that individuals with IFG or diabetes mellitus
monitor their condition and make healthy lifestyle choices to reduce the onset of these life
threatening symptoms. Pre-diabetic individuals who have abdominal obesity, high blood pressure,
high LDL cholesterol, low HDL cholesterol, and high levels of triglycerides in the blood
have an increased risk of developing type 2 diabetes mellitus. These risk factors are
known collectively as the metabolic syndrome. Recent evidence suggests that, similar to
diabetes mellitus, individuals with IFG have higher degree of periodontal inflammation.
Prevention
With proper education, eating habits, physical activity, weight management, and lifestyle
the risk of developing type 2 diabetes mellitus is reduced. Blood glucose levels can be managed
by the healthy eating and physical activity guidelines as an individual with normal blood
glucose levels, however some minor modifications may be required. These variations depend on
the individual, but it may include a slight decrease in the amount of carbohydrates consumed.
The consumption of alcohol should also be limited, but moderate drinking is protective.
Advice and guidelines about eating a nutritious, balanced meal can be found using Canada's
Food Guide. Vegetables and fruit should be consumed in the largest proportions. Regular
physical activity has the potential to reduce insulin resistance and help decrease elevated
blood glucose levels. References
See also Diabetic diet
Low GI diet Impaired glucose tolerance