Different contributions of insulin resistance and beta-cell dysfunction in overweight Israeli Arabs with IFG and IGT.
BACKGROUND
Impaired glucose tolerance (IGT) and impaired fasting glucose (IFG) are both intermediate stages that exist between normal glucose tolerance and overt type 2 diabetes. Epidemiological studies demonstrated that the two categories define distinct populations. In this study, we examined the contributions of insulin resistance and beta-cell dysfunction to both states in overweight subjects of Arab origin.


METHODS
Twelve subjects with isolated IFG, 10 with isolated IGT, and 20 with IFG and IGT (combined glucose in tolerance-CGT) were compared with 30 subjects with normal glucose tolerance (NGT) subjects; all were of Arab origin and were overweight or obese. Different indices for insulin resistance and beta-cell function were calculated from oral glucose tolerance (OGTT) values.


RESULTS
Subjects with isolated IFG and CGT were more obese and had significantly higher values of insulin resistance than subjects with isolated IGT and NFG. There was no significant difference between the insulin resistance in subjects with isolated IGT and that in subjects with NGT. Indices of beta cell function were severely reduced among subjects with isolated IGT and CGT when compared with those with both isolated IFG and NGT, while subjects with isolated IFG had similar beta-cell indices to subjects with NGT.


CONCLUSIONS
These data demonstrate that beta-cell dysfunction and insulin resistance contribute differently to the pathogenesis of IFG and IGT among overweight Arab subjects.
Abdul-Ghani
Muhammad A
MA
Department of Diabetes, Lin Medical Center, Clalit Health Services, Haifa and Diabetes Unit, Hadassah University Hospital, Jerusalem, Israel. muhammadag@hotmail.com
Sabbah
Muhammad
M
Kher
Joseph
J
Minuchin
Oscar
O
Vardi
Pnina
P
Raz
Itamar
I
D000328:Adult; D018912:Arabs; D019540:Area Under Curve; D001786:Blood Glucose / Q000032:analysis; D049628:Body Size; D005215:Fasting; D018149:Glucose Intolerance / Q000453:epidemiology*; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance; D000078790:Insulin Secretion; D007557:Israel; D008875:Middle Aged; D012016:Reference Values
D001786:Blood Glucose; D007328:Insulin