According to the degree of diabetic retinopathy, there was a significant difference in the average plasma GDF-15 levels (no diabetic retinopathy, 1114 ng/L; nonproliferative diabetic retinopathy, 1327 ng/L; proliferative diabetic retinopathy, 1445 ng/L; p for trend = 0.035) after adjustments for confounders. The gene discussed is GDF15; the disease is diabetic retinopathy.