Hamburg (dpa) - Diabetics are not only at higher risk of suffering a heart attack or stroke, they are also more susceptible to diseases of the eyes, kidneys and nervous system.

But in cases where blood-sugar levels are well controlled, and blood pressure and blood fat levels reduced, the risk is lower, according to Jens Kroeger from Germany's Centre for Diabetology in Hamburg.

Writing in the health magazine, Neue Apotheken Illustrierte, Kroeger says sugar levels are not the single, most important cause of narrowed blood vessels, but the interplay between blood-sugar, pressure and fat.

Kroeger has based his stance on a medical study carried out by researchers in Denmark. Around 80 per cent of diabetics examined in the study developed damage to their retinas during the 20 years following diagnosis.

A third showed signs of damage to their nervous system and one-fifth had problems with their kidneys.

"About half of all new dialysis patients are diabetics," says Kroeger. Together with higher blood pressure and raised blood-fat levels, obesity is another high risk cause of diabetes.

Kroeger recommends beginning every therapy of type 2 diabetes with intensive education of what constitutes the disease.