Insulin secretion and action show differences in impaired fasting glucose and in impaired glucose tolerance in Asian Indians.

BACKGROUND

The aim of the study was to compare the abnormalities in insulin secretion and insulin sensitivity in impaired fasting glucose (IFG) and in impaired glucose tolerance (IGT).

METHODS

Glucose tolerance was determined by oral glucose tolerance test in 289 non-diabetic subjects selected for this study (M : F, 160 : 129, mean age 42.2 +/- 11.0 (SD) years, mean body mass index (BMI) 24.9 +/- 4.2 kg/m(2)). Diabetic subjects were excluded from the study. The association of insulin resistance and beta-cell function (calculated by HOMA model) with IFG and IGT was studied using linear and multiple logistic regression analyses. Subjects with normoglycaemia (NGT) were used as controls.

RESULTS

Insulin resistance was significantly more in IFG and in IGT than in NGT. beta-cell dysfunction was significantly higher in IFG than in IGT. IFG was associated with both insulin resistance (OR = 9.11, p < 0.001) and beta-cell dysfunction (inverse correlation, OR = 0.103, p < 0.001), while only insulin resistance was significantly associated with IGT (OR = 1.24, p = 0.005).

CONCLUSIONS

In urban South Asian Indians, IFG differed from IGT in having combined insulin resistance and beta-cell dysfunction, while IGT was associated only with insulin resistance.