Of those people, 1,006 reported that they had been diagnosed with diabetes, or they had a hemoglobin A1C reading above 6.5 percent. Hemoglobin A1C is a measure of long-term blood sugar control, and according to the American Diabetes Association, someone who has a level of 6.5 percent or higher has diabetes. The study did not differentiate between type 1 and type 2 diabetes.
In addition to finding that nearly one in three people with diabetes has some form of diabetic retinopathy, the researchers also found that slightly more men than women have the disease (about 32 percent versus 26 percent), and blacks and Mexican Americans have a higher rate of the disorder than whites (about 39, 34 and 26 percent, respectively).
Other risk factors for diabetic retinopathy found in the study included a higher A1C level (which indicates poor blood sugar control), higher systolic blood pressure, a longer duration of diabetes and insulin use.
Zhang said that many of these risk factors, such as a high A1C or the need for insulin (in type 2 diabetics) might indicate more severe diabetes, which is more likely to result in diabetic retinopathy.
"I was surprised to see that there's still such a high prevalence of diabetic retinopathy," said Dr. Richard Bergenstal, president of medicine and science for the American Diabetes Association. "We've made a lot of progress in treating diabetes and the hope is always that the complications are going away, but we still have a lot of people who aren't quite to goal in terms of blood sugar management."
Bergenstal said that everyone with type 2 diabetes should have a dilated eye exam soon after they're diagnosed with diabetes, because they've likely had diabetes for a while without knowing it. After the initial exam, he said, a dilated eye exam is needed every ye
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