Background: Studies pertaining to association of GSTM1 and GSTT1 null genotypes with
risk of T2DM and its complications were often inconclusive, thus spurring the present study.
Methods: Meta-analysis of 25 studies for evaluating the role of GSTM1/GSTT1 null polymorphisms in
determining the risk for T2DM and 17 studies for evaluating the role of GSTM1/GSTT1 null polymorphisms
in development of T2DM related complications were conducted.
Results: Our study revealed an association between GSTM1 and GSTT1 null polymorphism with
T2DM (GSTM1; OR=1.37;95% CI =1.10-1.70 and GSTT1; OR=1.29;95% CI =1.04-1.61) with an amplified
risk of 2.02 fold for combined GSTM1-GSTT1 null genotypes. Furthermore, the GSTT1 null
(OR=1.56;95%CI=1.38-1.77) and combined GSTM1-GSTT1 null genotypes (OR=1.91;95%CI=1.25-
2.94) increased the risk for development of T2DM related complications, but not the GSTM1 null
genotype. Stratified analyses based on ethnicity revealed GSTM1 and GSTT1 null genotypes increase
the risk for T2DM in both Caucasians and Asians, with Asians showing much higher risk of T2DM
complications than Caucasians for the same.
Discussion: GSTM1, GSTT1 and combined GSTM1-GSTT1 null polymorphism may be associated with
increased risk for T2DM; while GSTT1 and combined GSTM1-GSTT1 null polymorphism may increase
the risk of subsequent development of T2DM complications with Asian population carrying an
amplified risk for the polymorphism.
Conclusion: Thus GSTM1 and GSTT1 null genotypes increases the risk for Type 2 diabetes mellitus
alone, in combination or with regards to ethnicity.