Serum total bilirubin levels and prevalence of diabetic retinopathy in a Chinese population.

BACKGROUND Patients with type 2 diabetes (T2D) are at a high risk of developing microvascular complications, such as diabetic retinopathy (DR). Previous studies have shown that low serum bilirubin concentrations in T2D patients may increase the risk of diabetic complications. Thus, the aim of the present was to investigate the association between the prevalence of DR and serum concentrations of total bilirubin in a Chinese population. METHODS The present study was a population-based cross-sectional study on 1761 T2D patients aged ≥40 years from the Jiading district of Shanghai, China. Fundus photographs were taken to confirm the presence and severity of DR. Subjects were assigned to quartiles based on serum total bilirubin concentrations (Quartile (Q) 1 <0.60 mg/dL; Q2 0.60-0.76 mg/dL; Q3 0.77-0.99 mg/dL; Q4 >0.99 mg/dL). Logistic regression models were used to explore the association between bilirubin concentrations and the prevalence of DR. RESULTS The prevalence of DR in the entire study population was 9.6%. The prevalence of DR was significantly lower in Q4 compared with the other three quartiles (Ptrend  = 0.004). After adjustment for multiple confounding factors, T2D patients in Q4 (i.e. serum bilirubin >0.99 mg/dL) were less likely (odds ratio 0.55; 95% confidence interval 0.33-0.91) to suffer from DR than patients in Q1 (i.e. serum bilirubin <0.60 mg/dL). CONCLUSION Serum bilirubin concentrations were inversely associated with DR in an elderly Chinese population, independent of traditional risk factors for microvascular complications.