Association of monocyte chemoattractant protein-1 gene 2518A/G polymorphism with diabetic retinopathy in type 2 diabetes mellitus: A meta-analysis

• This meta-analysis included 6 available studies that evaluated the role of MCP-1 gene in presence and progression of DR.
• The G allele and GG genotype of MCP-1 gene increase the susceptible to DR under the homozygous, heterozygous, dominant, recessive, and allelic models.
• The GA genotype of MCP-1 gene was significantly associated with increasing risk of PDR under the heterozygous model.

AimsThe relationship between monocyte chemoattractant protein-1 (MCP-1) 2518 A/G polymorphism and diabetic retinopathy (DR) attracted intense interest recently, but the reported results are controversial. A meta-analysis was performed to assess the MCP-1 polymorphism associated with DR susceptibility in type 2 diabetes mellitus.MethodsEligible studies were identified from PubMed, Embase, Web of science, Chinese Biomedical database, and references of retrieved articles. Pooled odds ratios (ORs) with their 95% confidence intervals (95%CI) were calculated by fixed or random-effects models.ResultsSix studies involving 3415 patients without DR and 3468 with any DR were included in the final meta-analysis. Each 5 studies evaluated the associations of MCP-1 polymorphism and any DR and proliferative DR (PDR), respectively. Meta-analysis in fixed model demonstrated a significant association between MCP-1 polymorphism and any DR under the homozygous model (OR = 1.36; 95%CI: 1.15–1.62, P < 0.001), heterozygous model (OR = 1.20; 95%CI: 1.02–1.42, P = 0.031), dominant model (OR = 1.28; 95%CI: 1.10–1.50, P = 0.002), recessive model (OR = 1.17; 95%CI: 1.05–1.31, P = 0.004), and allelic model (OR = 1.16; 95%CI: 1.07–1.25, P < 0.001). Furthermore, a significant association of MCP-1 polymorphism and DR progression from non-proliferative DR to proliferative DR was identified under heterozygous model (OR = 1.45; 95%CI: 1.04–2.02, P = 0.030). Sensitivity analyses did not draw different findings.ConclusionsMeta-analysis of existing data suggested that MCP-1 2518 A/G polymorphism affected the risk of presence and progression of DR in type 2 diabetes mellitus.