Diabetic eye disease raises dementia risk by 55 per cent and may strike years before memory loss begins

Scientists from Saudi Arabia, publishing in Frontiers in Endocrinology, established that the eye condition must precede cognitive decline, not merely coexist with it, making it a potential early warning sign. A separate University of Pittsburgh study, published in JAMA Psychiatry, found that adults with ADHD face more than four times the dementia risk after adjusting for age and other conditions.

Once regarded purely as a complication of high blood sugar, retinopathy is now understood to involve neuronal loss in the eye that sets in before any leaking occurs.

The ADHD study drew on electronic health records and genetic data from more than 187,000 adults aged 50 and over enrolled in a US federal research programme.