New research led by the University of Southern California (USC) Eye Institute, part of Keck Medicine of USC, identifies Native American ancestry as a notable risk factor for vision-threatening diabetic retinopathy in Latinos with Type 2 diabetes.
Published in the peer-reviewed journal Investigative Ophthalmology & Visual Science, the study offers the first evidence, to the authors’ knowledge, that genetic ancestry contributes to the risk of severe diabetic eye disease among Latino adults. Diabetic retinopathy—caused by damage to the tiny blood vessels in the retina—is the leading cause of blindness for working-age adults in the United States and affects millions of Americans aged 40 and older.
Diabetic retinopathy develops when chronically high blood sugar injures retinal blood vessels, causing them to swell, leak, or close off, and in advanced stages leading to new, fragile blood vessel growth. Early symptoms are often subtle or absent, but the condition can progressively reduce vision and ultimately cause blindness if untreated. Early detection and targeted interventions are vital to reduce vision loss from this condition.
The USC team analyzed data from 944 Latino participants with Type 2 diabetes enrolled in the Los Angeles Latino Eye Study (LALES), the largest population-based study of eye disease in this ethnic group. All participants were aged 40 or older and lived in La Puente, California; about 95 percent were of Mexican origin. Among these participants, 135 had vision-threatening diabetic retinopathy while 809 did not.
Latinos represent a genetically admixed population with varying proportions of Native American, European, and African ancestry. The study used genetic assays to estimate each participant’s ancestral background and combined that information with detailed ophthalmologic assessments to evaluate risk. After adjusting for established risk factors for diabetic retinopathy, the analyses showed that participants whose genomes indicated more than 50 percent Native American ancestry had an 87 percent greater odds of severe, vision-threatening diabetic retinopathy than participants with lower proportions of Native American ancestry.
“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, MD, MPH, director of the USC Eye Institute, 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 related to Native American ancestry.”
Lead author Xiaoyi Gao, who began this work while at USC and is now an associate professor of ophthalmology at the University of Illinois, Chicago College of Medicine, noted that the study provides a foundation for more targeted genetic investigations. “Our next steps will be to narrow down genomic regions of Native American origin that might increase the risk of developing severe diabetic retinopathy,” Gao said. Identifying specific genetic loci could help clarify biological mechanisms and eventually inform risk stratification and personalized prevention strategies.
Co-authors on the paper include W. James Gauderman, Paul Marjoram and Mina Torres of USC, and Yii-Der I. Chen, Kent Taylor and Jerome Rotter of the Los Angeles Biomedical Research Institute at Harbor-UCLA. The research received support from multiple funding sources, including the National Institutes of Health (grants U10EY011753, R01EY022651, P30EY001792), Research to Prevent Blindness, the National Center for Advancing Translational Sciences via the USC Clinical Translational Science Institute (grant UL1TR000124), and the National Institute of Diabetes and Digestive and Kidney Diseases Diabetes Research Center (grant DK063491).
This article was submitted directly to NeuroscienceNews.com by Alison Trinidad of USC.
Written by Alison Trinidad
Contact: Alison Trinidad – USC
Source: USC press release
Image Source: Image credited to BruceBlaus (Creative Commons Attribution 3.0).
Original Research: Abstract for “Native American ancestry is associated with severe diabetic retinopathy in Latinos” by Xiaoyi Gao, W. James Gauderman, Paul Marjoram, Mina Torres, Yii-Der Ida Chen, Kent D. Taylor, Jerome I. Rotter, and Rohit Varma in Investigative Ophthalmology & Visual Science. Published online August 21, 2014. doi:10.1167/iovs.14-15044