Different Aspects of Impaired Glucose Tolerance
and Fasting Glucose
People with isolated IFG were more resistant to insulin
than people with IGT, and that people with isolated
IGT showed a greater deficiency in the early and
late stages of insulin secretion.
Investigators for the Risk Factor in Impaired
Glucose Tolerance for Atherosclerosis and
Diabetes (RIAD)
study compared insulin secretion abnormalities
and insulin resistance related to isolated
impaired glucose
tolerance (IGT) and impaired fasting glucose
(IFG), two risk factors for type 2 diabetes.
People at high
risk of type 2 diabetes underwent a 75-gram oral
glucose tolerance test and were monitored at
half-hourly intervals for 2 hours for specific
insulin, proinsulin,
free fatty acids and C peptide.
After adjusting for sex, age and body mass index,
nondiabetic participants with hyperglycemia
were found to be at higher risk of cardiovascular
disease than people with normal glucose tolerance.
Analysis
of the importance of insulin resistance and
insulin
secretion abnormalities demonstrated that for
participants with IFG, insulin resistance was
the cause of 28.4%
of the difference from people with normal glucose
tolerance, and in people with IGT, the main
variance resulted from abnormalities in insulin
secretion
(31.1%).
It was concluded that people with isolated
IFG were more resistant to insulin than people
with
IGT, and
that people with isolated IGT showed a greater
deficiency in the early and late stages of
insulin secretion.
This suggests that alternative approaches
are needed for these patients in the primary
prevention
of type
2 diabetes. Diabetes Care 2003;26:868-874
