The damage -- called diabetic neuropathy -- affects the nerves of the body. It can lead to numbness, pain, and weakness in the hands, arms, feet, and legs. The condition is especially common among people who have had diabetes for a long time.
Neuropathy can make it harder to feel pain. That's dangerous, since pain is the body's injury alarm.
Some types of neuropathy can also harm the body's internal organs and systems. In those cases, problems can arise with the regulation of body temperature, digestion, urinary and sexual function, and the heart and blood vessels.
People who have had diabetes for long periods of time are at risk for nerve damage. However until now, poor blood sugar control was the only proven risk factor. But the suspect list just got longer, and the additions also endanger the heart.Diabetic and On Insulin? Take a Quality of Life Quiz.
New Risk Factors Found
Smoking, high levels of blood fats (such as cholesterol and triglycerides), high blood pressure, and greater BMI are among the newly identified and potentially modifiable risk factors for diabetic neuropathy.
The findings appear in the Jan. 27 issue of The New England Journal of Medicine. They're based on more than 1,100 people with type 1 diabetes in Europe.
Participants were studied twice during a seven-year period. They provided blood samples to determine glucose and cholesterol control, and urine samples to check for kidney damage. Researchers also tested the participants for nerve damage.
None had neuropathy at the beginning of the study. But within seven years, about 23% had developed the condition. That's fairly typical, say the researchers, who included Solomon Tesfaye, MD, of the Diabetes Research Unit at England's Royal Hallamshire Hospital.
People who developed neuropathy tended to have several things in common, including:
Age also mattered. People who developed diabetic neuropathy were nearly four years older, on average, than those without the condition. They had also had diabetes for about three additional years, and often had poorer control of their blood sugar.
A few other risk factors also stood out. Diabetes patients who developed neuropathy were more likely to have abnormally high levels of protein in their urine, which may indicate kidney problems.
The good news is that many of these risks are modifiable and can be improved. Many of these risk factors are heart disease risk factors and studies should be done to see if treating them also slows down the development of neuropathy, say the researchers.