A new study by researchers with the University of Southern California (USC) Eye Institute has found that Latinos with Native American ancestry who have type 2 diabetes have a significant risk of diabetic retinopathy – the leading cause of blindness in U.S. adults. Diabetic retinopathy affects more than more than 4 million Americans age 40 and older.
The disease occurs when blood vessels in the eye’s retina are damaged because of insufficiently controlled glucose levels. At first, a person suffering from the disease may not notice changes, but the condition can get worse over time and lead to blindness.
“This is the first study, to our knowledge, that examines the contribution of genetic ancestry in vision-threatening diabetic eye disease in Latinos,” said Rohit Varma, M.D., M.P.H., the study’s lead investigator who is also director of the USC Eye Institute and professor and chair of the Department of Ophthalmology at the Keck School of Medicine of USC.
“Previous research has shown that Latinos have a higher prevalence of diabetic retinopathy than non-Hispanic Whites and African-Americans,” Varma said. “Our findings suggest that one contributor to this heavy burden may be due to their Native American ancestry.”
The researchers looked at data on 944 Latinos with type 2 diabetes from the Los Angeles Latino Eye Study, the largest population-based study of eye disease among Latinos, the researchers say. They found that 135 had diabetic retinopathy.
Through a combination of genetic tests and eye exams, the researchers determined that study participants with more than 50 percent Native American ancestry had an 87 percent higher chance of also having vision-threatening diabetic retinopathy compared to those who had less than 50 percent Native American ancestry.
“Our next steps will be to try to narrow down which genomic locations among those with a Native American origin might be contributing to boosting the risk for developing severe diabetic retinopathy,” said Xiaoyi Gao, one of the study’s authors.
The researchers recommend that Native American ancestry be included as an assessment question for Latinos diagnosed with type 2 diabetes.
The study was published in in Investigative Ophthalmology & Visual Science.