Timing is everything: age of onset influences long-term retinopathy risk in type 2 diabetes, independent of traditional risk factors.
OBJECTIVE
To test the hypothesis that age of type 2 diabetes onset influences inherent susceptibility to diabetic retinopathy, independent of disease duration and degree of hyperglycemia.


METHODS
Retinopathy data from 624 patients with a type 2 diabetes duration of 20-30 years (group A) were analyzed by stratifying patients according to age of onset of diabetes and glycemic control. Retinopathy status was scored clinically as per a modified Early Treatment Diabetic Retinopathy Study (ETDRS) severity scale. To obviate possible bias due to a higher attrition from comorbidities in those with later-onset diabetes and retinopathy, 852 patients with type 2 diabetes of shorter duration (10-12 years, group B) were similarly studied.


RESULTS
Prevalence and severity of retinopathy was significantly higher in the younger-onset, group A patients. When further stratified according to mean A1C, retinopathy risk remained increased in younger-onset patients. The greatest impact was seen in those with a mean A1C >9% (odds ratio [OR] for retinopathy 16.6, 7.5, and 2.7 for age of diagnosis <45, 45-55, and >55 years, respectively, P = 0.003). By logistic regression, earlier type 2 diabetes onset is associated with increased retinopathy risk, independent of traditional risk factors (OR of retinopathy 1.9, 1.1, and 1 for age of onset <45, 45-55, and >55 years, respectively). Similar results were found in group B patients.


CONCLUSIONS
These data suggest an increased inherent susceptibility to diabetic retinopathy with earlier-onset type 2 diabetes. This further supports the importance of delaying development of diabetes and also implies a need for more stringent metabolic targets for younger individuals.
Wong
Jencia
J
Diabetes Centre, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia. jencia.wong@email.cs.nsw.gov.au
Molyneaux
Lynda
L
Constantino
Maria
M
Twigg
Stephen M
SM
Yue
Dennis K
DK
D000328:Adult; D017668:Age of Onset; D000368:Aged; D015992:Body Mass Index; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000150:complications* / Q000453:epidemiology; D003930:Diabetic Retinopathy / Q000453:epidemiology*; D004198:Disease Susceptibility; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D008055:Lipids / Q000097:blood; D008269:Macular Edema / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009517:New South Wales / Q000453:epidemiology; D012189:Retrospective Studies; D012307:Risk Factors
D006442:Glycated Hemoglobin; D008055:Lipids