New research led by the USC Eye Institute, shows for the first time that Native American ancestry is a significant risk factor for vision-threatening diabetic retinopathy among Latinos with Type 2 diabetes.
Diabetic retinopathy is the leading cause of blindness in working-age adults in the United States, affecting more than 4 million Americans age 40 and older.
Diabetic retinopathy occurs when blood vessels in the eye's retina are damaged. The retina is the light-sensitive tissue at the back of the eye that acts like a film inside a camera; like damaged film, a damaged retina will produce a bad picture. Symptoms may not be noticeable at first, but the disease can get worse over time and lead to vision loss.
“This is the first study, to our knowledge, that examines the contribution of genetic ancestry in vision-threatening diabetic eye disease in Latinos,” said USC Eye Institute Director Rohit Varma, professor and chair of the Department of Ophthalmology at the Keck School of Medicine of USC and the study's principal investigator. “Previous research has shown that Latinos have a higher prevalence of diabetic retinopathy than non-Hispanic whites and African-Americans. Our findings suggest that one contributor to this heavy burden may be due to their Native American ancestry.”
Latino ancestry
Latinos are a diverse group of people typically with a varying mixture of Native American, European and African ancestry. Varma's research team examined data from 944 Latinos with Type 2 diabetes from the Los Angeles Latino Eye Study, the largest population-based study of eye disease in that ethnic group. The participants in the study were 40 years of age or older and hailed from the city of La Puente.
Ninety-five percent of the participants were of Mexican origin. Of the 944 people with type II diabetes, 135 had vision-threatening diabetic retinopathy while 809 did not.
Using genetic assays and detailed ophthalmologic examinations, the team found that individuals 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, even after controlling for known risk factors for the disease.
Source: USC News, Native American ancestry a risk factor for diabetic eye disease in Latinosby Alison Trinidad, August 26, 2014.