by Amy Adams, MS
People with Type 1 or Type 2 diabetes are at a much higher risk than the general population for damage to the eyes, kidney, nerves, and blood vessels. Because of these serious risk factors, the American Diabetes Association recommends regular screening for early signs of damage. Many of these side effects can be delayed or avoided altogether through careful blood sugar control. In addition, a recent study has found that lowering blood sugar levels also lowers treatment costs for people with Type 2 diabetes.(For news about addition risks associated with high blood sugar levels, see Related News below.)
How does Blood Sugar Cause Damage?
I n people with diabetes, sugar (glucose) accumulates in the blood to very high levels. The excess glucose can attach toproteins in the blood vessels and alter their normal structure and function. One effect of this is that the vessels become thicker and less elastic, making it hard for blood to squeeze through.
Measuring Long-Term Blood Sugar Levels
Doctors can measure how much sugar has bound to proteins over a three to four month period using a glycated hemoglobin test. This test measures the amount of sugar that is attached to hemoglobin — a protein in red blood cells. Hemoglobin circulates in the blood for about three months, so by looking at the amount of sugars that have attached to hemoglobin, doctors have a good indication of how much sugar has bound to other proteins. This is an indication of your overall blood sugar control for that period of time. If the hemoglobin carries a lot of glucose, then there's a good chance that proteins in blood vessels have suffered some damage as well. On the other hand, hemoglobin without much bound sugar means that you had good blood sugar control and have a lower risk of tissue damage. Individuals with diabetes should have their hemoglobin screened several times a year to make sure their treatment plan is working.
Eye Damage
Diabetic eye disease starts when blood vessels in the back of the eye (the retina) balloon out into pouches. Although this stage — called nonproliferative retinopathy — generally does not affect vision, it can progress to a more serious form called proliferative retinopathy. This occurs when damaged blood vessels close off and new, weaker vessels take their place. These new vessels can leak blood, which blocks vision. They can also cause scar tissue to grow and distort the retina.
Because the retina can be irreversibly damaged before you notice any change in vision, and because retinopathy can be effectively treated with lasers to minimize vision loss, the American Diabetes Association recommends screening for retinopathy yearly.
Kidney Disease
Kidney disease starts when the blood vessels in the kidney become leaky. These leaky vessels allow protein from the blood to be excreted with urine. (It's this protein that doctors detect when they test for kidney function.) Eventually, some vessels collapse and place more pressure on those that remain. Under this increased load, the remaining blood vessels are also damaged and the kidney may fail. If the disease progresses to this point, a person may have to go on dialysis — where a machine performs the role of the kidney — or receive a kidney transplant.
Because of the serious consequences of kidney disease, the American Diabetes Association recommends screening for protein in the urine every year starting at the time of diagnosis, or five years after the diagnosis in Type 1 diabetics.
Heart and Blood Vessel Disease
High blood sugar damages blood vessels and can lead to blockage. In the heart, this blockage can cause heart attacks. In fact, people with diabetes have two to four times the risk of developing heart disease or stroke than the general population. Blocked vessels in the legs can cause pain and can also impair circulation. With poor circulation, small cuts or infections are less likely to heal. Eventually, 0.6 percent of all diabetics have lower limb amputations because of damage to the feet or lower legs.
Nerve Disease
In diabetes, the nerves that become damaged are the ones that allow you to sense temperature, pressure, texture, or pain on your skin. In most people with diabetes, nerve disease (neuropathy) effects the feet and lower legs, causing numbness or tingling. The real problem arises when numbness allows injuries to the foot to go unnoticed. For this reason, the American Diabetes Association recommends that all people with diabetes have a thorough foot exam every year.
Reviewed by Jeremy Walston, MD
Last updated September 20, 2000
Forwarded by Dr. Muhammad Danish Janjua, Sahiwal
Dr. Danish is engaged in research on diabetes with a team of Bulgarian doctors.