The Relationship Between Aldose Reductase C106T Polymorphism and Diabetic Retinopathy: An Updated Meta-Analysis

PURPOSE. Studies investigating the associations between aldose reductase (ALR) genetic polymorphisms and diabetic retinopathy (DR) have reported controversial results. Therefore, to shed light on these inconclusive findings, we performed this meta-analysis to clarify the effects of ALR C(-106) T polymorphism on DR risk. METHODS. Relevant studies were selected through an extensive search of PubMed, EMBASE, the Web of Science databases and Chinese National Knowledge Infrastructure, VIP, and Wan Fang databases in Chinese. Pooled odds ratio (OR) and 95% confidence interval (CI) were calculated by using random-effects model. RESULTS. The present meta-analysis included 3512 diabetes mellitus (DM) patients with DR and 4319 DM patients without DR. Overall, the pooled ORs showed a nonsignificant association between ALR C(-106) T polymorphism and DR susceptibility in all genetic models (C allele versus T allele: OR = 1.08, 95% CI = 0.90-1.29; CT/TT versus CC: OR = 0.90, 95% CI = 0.72-1.13; TT versus CT/CC: OR = 0.87, 95% CI = 0.69-1.10; TT versus CC: OR = 0.87, 95% CI = 0.64-1.18; CT versus CC: OR = 0.93, 95% CI = 0.73-1.19). No significant association was detected between ALR C(-106) T polymorphism and non-proliferative diabetic retinopathy or proliferative diabetic retinopathy. An additional analysis showed that the association of C(-106) T polymorphism with DR was significant in type 1 DM (C allele versus T allele: OR = 1.78, 95% CI = 1.39-2.28; CT/TT versus CC: OR = 0.49, 95% CI = 0.36-0.68; TT versus CT/CC: OR = 0.48, 95% CI = 0.28-0.84; TT versus CC: OR = 0.33, 95% CI = 0.17-0.67; CT versus CC: OR = 0.52, 95% CI = 0.37-0.74) but not in type 2 DM. CONCLUSIONS. The results of this meta-analysis showed that ALR C(-106) T polymorphism was not associated with an increased risk of DR. However, subgroup analysis showed a genetic association between ALR C(-106) T polymorphism and the risk of DR of type 1 DM but not DR of type 2 DM.