Evidence of interaction between type 2 diabetes susceptibility genes and dietary fat intake for adiposity and glucose homeostasis-related phenotypes.
ABSTRACT Genome-wide association studies have led to the identification of several susceptibility genes for type 2 diabetes mellitus (T2DM). The objective of this study was to test the hypothesis that the associations between single nucleotide polymorphisms (SNPs) in these genes and adiposity and glucose homeostasis-related phenotypes are influenced by dietary fat intake.
Thirty-three SNPs in 9 T2DM genes (CDKAL1, CDKN2A/B, HHEX, HNF1B, IGF2BP2, KCNJ11, SLC30A8, TCF7L2 and WFS1) were tested in a maximum of 669 subjects from the Quebec Family Study. Subjects were measured for several adiposity indices and underwent a 75-gram oral glucose tolerance test. Total fat intake was estimated from a 3-day dietary record.
We observed 13 significant (p < or = 0.01) SNP-dietary fat interactions. Among them, IGF2BP2 rs4402960, alone or in interaction with dietary fat intake, influenced abdominal total fat (ATF: SNP effect, p = 0.006, interaction effect, p = 0.009) and abdominal visceral fat (AVF: SNP effect, p = 0.007, interaction effect, p = 0.01). Similarly, TCF7L2 rs12573128 alone or in interaction with dietary fat intake, influenced insulin sensitivity (SNP effect and interaction effect, p < or = 0.008) and glucose tolerance (SNP effect p < or= 0.009 and interaction effect, p < or = 0.01).
These results suggest that gene-dietary fat interactions may influence glucose homeostasis-related phenotypes and play an important role in determining the increased risk of diabetes associated with the T2DM susceptibility genes.
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ABSTRACT: Type 2 diabetes mellitus (T2DM) is the most common form of diabetes characterized by elevated levels of plasma glucose caused by impairment in both insulin secretion and action. It is becoming an epidemic leading to various complications and its prevalence and incidence are increasing at an alarming rate in developing countries like India, raising a major public health concern. Both the genetic and environmental factors play a strong role in the manifestation of this complex genetic disorder. In the recent years, there has been a spate of molecular genetic investigations, including whole genome scans, to test the association of genetic variants with T2DM in different patho-physiological pathways. A large number of candidate genes have been identified to be associated with T2DM, albeit only a couple of them show consistency in association in different populations/ethnic groups. Given relatively high risk for T2DM in India and immense genetic heterogeneity and substructure of the constituent populations, the number of studies is too small to be able to characterize the genetic basis of the disease in India. The recent dramatic increase in number of affected people indicates that lifestyle factors related to urbanization and sedentary occupations may be particularly important in triggering the genetic elements that cause this type of diabetes. Therefore, it is imperative to precisely establish the underlying genetic and environmental factors behind this complex genetic disorder so that preventive measures can be initiated. We have attempted to review the molecular genetic studies conducted, till date, globally on T2DM along with the epidemiological, environmental and ethnic factors implicated in the manifestation of T2DM.Int J Diabetes Dev Ctries. 06/2011;