Is prevalence of retinopathy related to the age of onset of diabetes? Sankara Nethralaya Diabetic Retinopathy Epidemiology and Molecular Genetic Report No. 5.

AIM

To compare the prevalence of diabetic retinopathy (DR) and risk factors in patients with a known onset of diabetes before 40 years and after 40 years of age.

METHODS

This is a population-based study for which 1,414 diabetics were recruited. The fundi were photographed using 45-degree 4-field stereoscopic digital photography. The diagnosis of DR was based on Klein's classification of the Early Treatment Diabetic Retinopathy Study scales.

RESULTS

The prevalence of DR was 33.3% (95% confidence interval, CI: 26.6-39.9) in known onset of diabetes (≤ 40 years) compared to 15.6% (95% CI: 13.6-17.6) in those with late onset (> 40 years; p < 0.0001). In the group with age of known onset of diabetes ≤ 40 years, the risk factors, associated with any DR, were poor glycemic control (odds ratio, OR: 1.36 for every g% increase in glycosylated hemoglobin), insulin use (OR: 4.21), increasing known duration of diabetes (OR: 1.10 for increase of every year in known duration of diabetes) and presence of macroalbuminuria (OR: 13.39). In the late onset of diabetes group, besides the above-mentioned risk factors, the presence of microalbuminuria (OR: 2.08), male gender (OR: 1.67), presence of anemia (OR: 1.89) and increased systolic blood pressure (OR: 1.01) were the risk factors for DR.

CONCLUSION

The prevalence of DR was almost twice more in those subjects who developed diabetes before the age of 40 years than those who developed it later.