Evaluation of simpler methods for the assessment of insulin sensitivity in Egyptians

ABSTRACT

Aim: A number of insulin sensitivity indices are frequently used. These are fasting insulin [I], 40/1, HOMA-IR, n[HOMA], 1/HOMA, I/G, and G/l, where G and I are the fasting glucose, and insulin concentrations, respectively. To test the validity of these simple indices in Egyptians, their values were computed and correlated with the MINMOD-derived S1 value. Subjects and The present study was carried out on 40 Egyptian subjects [15 obese and 25 nonobese]. The weight and height were measured from which the BMI was calculated. Skinfold thickness was measured from the biceps, triceps, subscapular and supra-iliac region. The body fat content was calculated. Waist and hip circumference were measured from which waist/hip ratio was calculated. All subjects underwent a 75 g OGTT followed, at least 7 days later, by an FSIVGTT. Plasma glucose was determined and serum insulin was measured by EASIA. Insulin sensitivity, S1, and glucose effectiveness, SG, were calculated with the MINMOD program. The insulin sensitivity indices were also calculated from the fasting insulin [I], fasting glucose [G], 40/I, HOMA-IR, In [HOMA], 1/HOMA and G/l. A significant correlation was found between S1, and I, 40/I, HOMA-IR, in [HOMA], 1/HOMA, I/G and G/l. Ln [HOMA], G/l, 40/I and HOMA-IR correlated better with MINMOD S1, than I, 1/HOMA, I/G and G. Conclusions: These simple S1 indices give only approximate values which cannot be counted upon in all cases. Further studies are needed to characterize the validity of these simple indices in terms of the factors responsible for insulin sensitivity, to validate these measures in different populations and to clarify the differences between different studies