Association between diabetic retinopathy in type 2 diabetes and the ICAM-1 rs5498 polymorphism: a meta-analysis of case-control studies

BackgroundGenetic studies have reported contradictory results on the association between the intercellular adhesion molecule-1 (ICAM-1) rs5498 polymorphism and diabetic retinopathy (DR) risk in type 2 diabetic patients. We aimed to perform a systematic literature search and conduct random-effects meta-analysis to provide a quantitative evaluation.MethodsWe searched Pubmed, Embase, Scopus, Web of Science and Wanfang databases from inception up to January 2018. Allelic and genotype frequencies of rs5498 was compared between DR cases and controls. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using a random effects model.ResultsNine studies involving a total of 1792 cases and 1400 controls met our inclusion criteria. We did not find any significant association between rs5498 and DR risk at the dominant model (GG+GA versus AA, OR=1.00, 95% CI: 0.66-1.50, P=0.987), the recessive model (GG versus GA+AA, OR=1.24, 95% CI: 0.86-1.77, P=0.245), the GG versus AA contrast (OR=1.14, 95% CI: 0.68-1.92, P=0.611), and the G allele versus A allele contrast (OR=1.08, 95% CI: 0.81-1.45, P=0.592). Subgroup analysis by ethnicity showed no association in Asian populations (G allele versus A allele: OR=1.05, 95% CI: 0.76-1.44, P=0.790). Subgroup analysis by DR subtype also did not reveal any association of rs5498 with proliferative DR (G allele versus A allele: OR=1.34, 95% CI: 0.71-2.52, P=0.364) and non-proliferative DR (G allele versus A allele: OR=0.71, 95% CI: 0.43-1.17, P=0.180).ConclusionOur meta-analyses provide no evidence of the association of rs5498 with DR in type 2 diabetic patients.