Background: The disposition index represents insulin secretion related to the degree of insulin sensitivity, being constant for given degree of glucose tolerance. The aim of this study is to discern genetic determinants influencing the value of disposition index, e.g. predisposition to glucose intolerance.
Methods and results: Two hundred and four non-diabetic subjects with varied glucose tolerance were divided into groups according to the values of disposition index. Glucose and lipid metabolism, anthropometric parameters and family history of type 2 diabetes mellitus (DM2) were examined. The genotype frequency of candidate genes was compared between the groups of individuals within the lowest (Q1) and the highest (Q4) quartiles of the disposition index values. Those groups were not different concerning age and female to male ratio. Fasting and stimulated parameters of glucose metabolism and lipid profile were worse in group Q1 compared to group Q4. Group Q1 is characterized with higher number of individuals with metabolic syndrome and family history of DM2. The examination of candidate genes revealed the differences in genotype frequency of B2AR (rs1042714), PPARA (rs1800206), KCNJ11 (rs5219), and SLC30A8 (rs13266634) between groups Q1 and Q4.
Conclusions: Low value of disposition index is related to the deterioration of glucose tolerance and other signs of metabolic syndrome. It is associated with genes affecting insulin secretion and genes related to energy metabolism and obesity.