Nordwall M, et al. - In a population-based observational study, researchers assessed sex, age at diabetes onset, puberty, and HbA_1c, with subjects followed from diabetes diagnosis and during different time periods, as risk factors for developing diabetic simplex and proliferative retinopathy. HbA_1c was followed up to 18–24 years after diagnosis in southeast Sweden for 451 patients in whom diabetes was diagnosed before the age of 35 in 1983–1987. Long-term mean weighted HbA_1c (wHbA_1c) was calculated. Findings suggested an association of onset at ≤ 5 years of age and lower wHbA_1c the first 5 years after diagnosis with longer duration before the development of simplex retinopathy. A strong positive association was found between long-term mean HbA_1c measured from diagnosis and up to 20 years and appearance of both simplex and proliferative retinopathy.