African vs. Caucasian and Asian difference for the association of interleukin-10 promotor polymorphisms with type 2 diabetes mellitus (a meta-analysis study).

BACKGROUND Interleukin-10 (IL-10) is a multifunctional regulatory cytokine that might be associated with increased risk of type 2 diabetes mellitus (T2DM). IL-10 gene polymorphisms have been reported to be associated with T2DM in several ethnic populations with controversial results. OBJECTIVES This work is an updated meta-analysis aiming at the evaluation of the association between IL-10 gene polymorphisms: rs1800872 (- 592 C > A), rs1800896 (- 1082 A > G) and rs1800871 (- 819 C > T) with the risk of T2DM. METHODS All available full text studies published up to July 2015 were included in this meta-analysis. Mainly Pubmed and Science Direct databases were searched for all eligible studies pertinent to testing the association between IL-10 gene polymorphisms with the susceptibility to T2DM. Further analyses of the pooled and stratified data in terms of individual polymorphic types and subject ethnicity were done and assessed using varied genetic models. RESULTS Fifteen case-control studies with a total of 26 comparisons (10 for IL-10 - 592 C > A rs1800872, 11 for IL-10 - 1082 A > G rs1800896 and 5 for IL-10 - 819 C > T rs1800871 polymorphisms) met our inclusion criteria. IL-10 - 1082 A > G polymorphism was the only one to show an association with T2DM in all pooled sample particularly among Asian and European (high frequency of the G allele) ethnic groups. On the other hand, IL-10 - 592 C > A and - 819 C > T were significantly associated with T2DM only among African subjects. CONCLUSIONS This meta-analysis demonstrated that IL-10 - 1082 A > G polymorphism was associated with increased risk of development of T2DM in total subjects no matter was their ethnic background, while both IL-10 - 592 C > A and - 819 C > T polymorphisms were associated with that risk only among African subjects.