Cross-Sectional and Longitudinal Changes of Glucose Effectiveness in Relation to Glucose Tolerance: The Insulin Resistance Atherosclerosis Study

Division of Clinical Epidemiology, University of Texas Health Science Center, San Antonio, TX, USA.
Diabetes care (Impact Factor: 8.42). 07/2011; 34(9):1959-64. DOI: 10.2337/dc10-2120
Source: PubMed


Glucose effectiveness (S(G)), the capacity of glucose to enhance its own disposition, is an independent predictor of future diabetes. However, there are data on cross-sectional and longitudinal changes of S(G) and its components, basal insulin effect on S(G) (BIE) and S(G) at zero insulin (GEZI), but the natural course of S(G) has not been described in a large population.
S(G) was measured at baseline in 1,265 participants (aged 40-69 years) and at the 5-year examination in 827 participants in the Insulin Resistance Atherosclerosis Study (IRAS) using the frequently sampled intravenous glucose tolerance test. None of these participants were treated with glucose-lowering agents.
In cross-sectional analyses, S(G), BIE, and GEZI deteriorated with worsening of glucose tolerance (P < 0.001 for all three associations). In longitudinal analyses among subjects with normal glucose tolerance (NGT) at baseline, S(G), BIE, and GEZI declined in those who progressed to impaired glucose tolerance (IGT) or diabetes (P < 0.001 for all three measures). More modest longitudinal changes were demonstrated in individuals with IGT. The transition back to NGT (as opposed to no change) compared with the transition to diabetes was statistically significant for S(G) (P = 0.049) and BIE (P = 0.042) and was not a statistically significant trend for GEZI (P = 0.332). In individuals with diabetes, only BIE had a significant decline (P = 0.003).
S(G), BIE, and GEZI decline in subjects whose glycemic status worsens. S(G) and GEZI deteriorate more in the initial stages of the disease process.

12 Reads
  • [Show abstract] [Hide abstract]
    ABSTRACT: Aim of this study was to formulate an index for glucose effectiveness (Sg), SgIo, based on 3-point (0, 30 and 120 min) 75 g oral glucose tolerance test (OGTT). The equation for SgI(O) was developed in the Chikuma cohort (n = 502). Firstly, post-loading plasma glucose without insulin action and Sg (PPG-without insulin and Sg) was calculated as follows: fasting plasma glucose (mg/dl) + [0.75 × 75,000]/[0.19 × BW(kg) × 10]. Secondly, 'PPG-without insulin/with Sg' was obtained from inverse correlation between log(10)DI(O) and 2-h post-glucose plasma glucose at OGTT (2hPG) in each glucose tolerance category: DI(O) denotes oral disposition index, a product of the Matsuda Index and δIRI(0-30)/δPG(0-30). Thirdly, expected 2hPG (2hPG(E)) of a given subject was obtained from the regression, and the ratio of 2hPG to 2hPG(E) (2hPG/2hPG(E)) was determined as an adjustment factor. Lastly, SgI(O) ([mg/dl]/min) was calculated as [Formula: see text]. SgI(O) was validated against Sg obtained by frequently sampled intravenous glucose tolerance test in the Jichi cohort (n = 205). Also, the accuracy of prediction of Sg by SgIo was tested by the Bland-Altman plot. SgI(O) was 3.61 ± 0.73, 3.17 ± 0.74 and 2.15 ± 0.60 in subjects with normal glucose tolerance (NGT), non-diabetic hyperglycemia and diabetes, respectively, in the Chikuma cohort. In the Jichi cohort, SgI(O) was significantly correlated with Sg in the entire group (r = 0.322, P < 0.001) and in subjects with NGT (r = 0.286, P < 0.001), and SgIo accurately predicted Sg. In conclusion, SgI(O) could be a simple, quantitative index for Sg.
    Acta Diabetologica 07/2012; 49(S1). DOI:10.1007/s00592-012-0417-y · 2.40 Impact Factor


12 Reads
Available from