Abstract
Saudi and Caucasian subjects, matched for adiposity, and of differing glycaemic status were compared using several insulin sensitivity indices and to also to assess insulin, glucose and insulin-like growth factor binding protein-1 (IGFBP-1) responses to intravenous glucose.
Subjects with normal glucose tolerance (NGT;
n
=
24), impaired fasting glucose (IFG;
n
=
12), impaired glucose tolerance (IGT;
n
=
12), and type 2 diabetes (DM;
n
=
13) were recruited from Saudi (
n
=
33) and Caucasian (
n
=
28) populations. All had specimens taken in the context of a standard oral glucose tolerance test at their first visit and had the insulin sensitivity parameter (Si) determined by frequently-sampled intravenous glucose tolerance test (FSIVGTT) at a second visit.
Saudis in the NGT and pooled glucose intolerance categories had significantly higher diastolic blood pressure (
p
<
0.001,
p
<
0.05 respectively) and HbA1c (
p
<
0.01,
p
<
0.05 respectively) compared to Caucasians. Caucasians in the NGT category had significantly higher Si, fasting and 2
h IGFBP-1 (
p
<
0.01,
p
<
0.05 and
p
<
0.01 respectively) compared to Saudis. Two hours following oral or intravenous glucose serum IGFBP-1 decreased to 44% (
p
<
0.001) and 50% (
p
<
0.05) of baseline levels respectively.
Our data suggest that adult Saudis with normal glucose tolerance appear to be more insulin resistant than Caucasians matched for adiposity. In normal individuals at 2
h the IGFBP-1 level will be about half the baseline level regardless of the route of glucose administration.