Insulin resistance & secretion in subjects with normal fasting plasma glucose.
OBJECTIVE
Lowering the diagnostic threshold of normal fasting plasma glucose (FPG) from 6.1 to 5.56 mmol/l has been proposed by American Diabetes Association. As early detection of subjects with risk of diabetes is important, it is crucial to understand the relationship between different levels of FPG, insulin resistance (IR) and insulin secretion. We measured IR and insulin secretion in subjects with different levels of FPG to investigate the relationship between FPG and IR and insulin secretion, and to see whether lowering the cut-off improves the sensitivity of impaired fasting glucose to predict diabetes.


METHODS
Apparently healthy subjects (294) were enrolled and divided into 3 groups according to their FPG levels; group 1 (<5.56 mmol/l, n=129), group 2 (5.56-6.09 mmol/l, n=99) and group 3 (6.1-6.9 mmol/l, n=66). Steady state plasma glucose (SSPG) derived from insulin suppression test was used to quantify insulin resistance and 30 min insulinogenic index during an oral glucose tolerance test to measure acute insulin secretion.


RESULTS
The blood pressure was higher in group 3 than group 2 and fasting plasma insulin and triglyceride were higher in group 3 than that in group 1. The insulinogenic index was higher in the group 1 than group 3 and the SSPG was significantly higher in group 3 compared to group 1.


CONCLUSIONS
Our study showed a trend of progressive deterioration of both insulin action and secretion with increasing FPG level. These are supportive evidences for lowering the FPG to 5.56 mmol/l as suggested by the ADA.
Hsieh
Chang-Hsun
CH
Division of Endocrinology & Metabolism, Department of Internal Medicine, Tri-Service General Hospital, Taipei, Taiwan.
Hung
Yi-Jen
YJ
Wu
Chung-Ze
CZ
Lee
Shang-Sen
SS
Lee
Chien-Hsing
CH
Chen
Cheng-Yu
CY
Li
Jur-Chuan
JC
Kuo
Shi-Wen
SW
Kuo
Ko-Lin
KL
Pei
Dee
D
D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis*; D005215:Fasting / Q000097:blood*; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance; D000078790:Insulin Secretion; D008297:Male; D008875:Middle Aged
D001786:Blood Glucose; D007328:Insulin