An association between IL-10 promoter polymorphisms and diabetic nephropathy: a meta-analysis of case-control studies

This study aimed to synthesize evidence on the association between IL-10 gene (-819 C/T, -1082 A/G, -592 A/C) polymorphisms and the risk of developing diabetic nephropathy.

A systematic literature search was done in health-related electronic databases. The search was limited to studies published in English until September 2017. We also checked the references of retrieved articles and relevant reviews for any additional studies. The methodological quality of the studies included in this review was assessed using the 'Scales for Quality Assessment'. The I ² test was used to quantify between-study heterogeneity. A value of I ² > 50% indicated substantial heterogeneity. For the pooled analysis, summary odds ratio (OR) and its 95% confidence interval (CI) in random effect model were used.

Eight case-control studies (1192 cases with diabetic nephropathy and 2399 controls) met the inclusion criteria. Three groups of people namely Africans, Asians and Caucasians were included in this review. There were significant protective effects of SNP -819 C/T in overall population (OR 0.32, 95% CI 0.26-0.4) and - 1082 A/G SNP in the Asian population (OR 0.64, 95% CI 0.47-0.86) on diabetic nephropathy in the recessive model. There was no significant effect of -592 A/C on diabetic nephropathy.

The findings suggest the protective effects of -1082A/G and -819G/A polymorphisms on the risk of developing diabetic nephropathy in type 2 diabetes mellitus, especially in the Asian population. Well- designed, prospective studies with sufficient number of participants are recommended to substantiate these findings.