African-Caribbean people with type 2 diabetes at higher risk of diabetes-related eye complications

Professor Janaka Karalliedde, Clinical Professor of Diabetes, King’s College London and lead study author, said: “Diabetes-related eye disease is the leading cause of sight loss in working age adults in the UK and many countries worldwide. Our results highlight the need for further research on the role of ethnicity and associated mechanisms that may explain enhanced risk of diabetic retinopathy progression.”

Diabetic retinopathy is a term used to describe the damage diabetes causes to the small blood vessels in the retina – the light-sensitive layer at the back of the eye.

STDR is a related complication and reflects when diabetic retinopathy has progressed to a stage where there is a risk of losing vision.

Although often symptomless at the beginning, damage from long-term blood glucose can cause changes to speed up and cause irreversible vision loss if untreated. 

Professor Karalliedde and colleagues at King’s College London recruited adults with type 2 diabetes and no diabetic retinopathy. They then studied clinical, biochemical and socio-economic data from these individuals by collecting their results from the UK National Diabetic Eye Screening Programme, which tests people with type 2 diabetes annually.

Referenced figures were collected between 2004 and 2018, and participants were followed over an average of 8.9 years each.  

Over the course of the study, 489 people – nearly 6% - developed STDR. The researchers used statistical analysis techniques to separate the individual risk factors, revealing that African-Caribbean ethnicity led to a 35% higher likelihood of developing STDR alone. This effect was independent of well-known risk factors such as longer diabetes duration, high cholesterol, high blood sugar levels and socio-economic deprivation. 

Dr Evelyn Mensah, Consultant Eye Surgeon, President Ophthalmology Section of the Royal Society of Medicine, London North West University Healthcare NHS Trust, said: “This important study highlights a reality many of us in eye care have long suspected which is that people of African-Caribbean heritage living with type 2 diabetes face a higher risk of sight threatening retinopathy, even after accounting for blood glucose, cholesterol and deprivation.

“In ophthalmology, we see similar disparities in glaucoma, where Black people tend to develop disease earlier and present later with more advanced vision loss. And beyond eyes, the same patterns are mirrored in breast cancer, prostate cancer and maternal mortality. The relevance of systemic factors should be considered in future research.

“With diabetes eye screening intervals increased to every two years for low-risk groups, we must be careful not to apply a blanket approach that risks widening health inequities. Screening programmes and hospital eye services must respond to the needs of diverse communities if we are to ensure excellent visual outcomes for all.”

On publication of their report, the researchers called for more work to understand why African-Caribbean ethnicity is linked to greater STDR risk, including possible genetic, biological and social mechanisms. They also suggested that healthcare providers should consider ethnicity as a potential risk factor when assessing and monitoring eye disease in people with diabetes. 

Read the report in Diabetes Care

Read more about type 2 diabetes

Read the DRWF diabetes information leaflet Eye health and diabetes