Background: Insulin-like growth factor (IGF) binding protein-3 (IGFBP-3) is a major determinant of circulating levels of the IGFs and is clinically useful for the evaluation of GH deficiency and for predicting the response to GH treatment. Circulating levels of IGF-1 and IGFBP-3 vary considerably among individuals and have been implicated in various medical conditions. We investigated the IGFBP-3 genotype distribution in Korean elderly and relations between IGFBP-3 promoter -202 locus A/C polymorphism and medical conditions.
Methods: Single nucleotide polymorphism at the -202 locus of the IGFBP-3 promoter was genotyped for 100 samples from a study population who is older than 60 years.
Results: The frequency of each polymorphic variation at the -202 locus in these study population was AA=43 (43%), AC=48 (48%), and CC=8 (8%). In both genders, the subjects with the CC genotype were taller, whereas those with AC genotype had higher weight, BMI and BSA comparing those with the other genotypes, but these facts did not reach statistical significance. The prevalence of type 2 DM and the mean fasting blood glucose level did not differ among genotypes in the female gender. In the male population, however, the prevalence of type 2 DM was higher in the subjects with the AC genotype (P=0.016) which is reflected by the elevated mean fasting glucose level (P=0.106).
Conclusion: IGFBP-3 promoter -202 locus A/C polymorphism, which reflects its serum level and further implicates IGFs bioactivity, was associated with a higher prevalence of type 2 DM in the male gender, suggesting IGFBP-3 might play a role in blood glucose homeostasis.