Depression boosts blindness risk for diabetics

NEW YORK, Aug 24 (Reuters) African Americans with type 1 diabetes who are depressed are more likely to have poor control over their blood sugar levels and, over time, experience a more rapid progression of diabetic retinopathy, a new study shows.

In previous research with the same group of patients, Dr Monique S Roy of UMDNJ-New Jersey Medical School in Newark and her colleagues found that poor control over blood sugar (glucose), high blood pressure and kidney disease were primary medical risk factors for diabetic retinopathy, damage to the blood vessels around the retina. However, these factors only explain 37 per cent of the variation in retinopathy severity in these patients.

Depression is known to increase inflammation and it has also been tied to hormonal changes and blood clotting abnormalities, all of which might play a role in progression of diabetic retinopathy, Roy told Reuters Health. ''It's a complex problem, and we're trying to untangle that,'' she said in an interview.

Although previous studies have linked depression with a greater risk of diabetic retinopathy and other blood vessel problems in diabetics, nearly all have looked at only a single time point, Roy and her team note in the current issue of Psychosomatic Medicine.

To provide a clearer idea of how depression might affect diabetic retinopathy risk and its progression over time, the researchers evaluated data from 483 African-American men and women with type 1 diabetes who completed a depression survey between 1993 and 1998, and again 6 years later.

Roy's team found that patients with high depression scores at the study's outset and at follow-up had significantly worse long-term blood glucose control. They were twice as likely to show progression of diabetic retinopathy during the course of the study.

Depressed individuals also had more than a three-fold greater risk of developing the most severe, rapidly progressing form of the disease, proliferative diabetic retinopathy.

Depression is common among people with diabetes, Roy noted, with up to 25 per cent of individuals with diabetes developing major depression at some point in their lives, compared with a 10-per cent rate in people without diabetes or other chronic health problems.

Recent studies have demonstrated that depression boosts the risk of other diabetes complications, she added, such as kidney disease and stroke.

The good news, Roy points out, is that depression can be treated successfully in diabetics.

''I think depression should really be looked for in people who have diabetes, not only by their retinal specialist but by their endocrinologist,'' she concludes.

REUTERS AK BST0430