Background: The role of genetic factors in diabetic retinopathy (DR) is unclear. We investigated the relationship between DR and an insertion/deletion polymorphism in the angiotensin-converting enzyme (ACE) gene in Iranian patients with type 2 diabetes without overt nephropathy.
Methods: A total of 178 consecutive type 2 diabetic patients with DR (Group A) and 206 type 2 diabetic patients without DR (Group B) were studied. The following variables were determined: age, sex, body mass index, diabetes duration, medications used, history of coronary artery disease and its complications, blood pressure (systolic and diastolic), fasting plasma glucose, hemoglobin A1c, total cholesterol, low- and high-density lipoproteins, triglycerides, plasma creatinine, and 24-h urine albumin excretion.
Results: The groups were statistically similar in all variables except diabetes duration (P = 0.037), ACE activity (P < 0.001), and ACE genotype (P = 0.008). The DD genotype was significantly more common in Group A (32.6% versus 19.2% in Group B; P = 0.009). In multivariate regression analysis, the ID genotype (compared to the II genotype) was an independent predictor of DR (OR = 1.831, 95% CI = 1.074-3.124; P = 0.026).
Conclusions: The D allele of the ACE gene is independently associated with DR in Iranian type 2 diabetic patients.