A new study reveals an unexpected factor that may predict your susceptibility to a serious autoimmune disease: eye color.
Researchers have discovered a link between blue eyes and increased risk of developing type 1 diabetes. Their findings, published 2011 in Diabetes/Metabolism Research and Reviews, show that individuals with light-colored irises are more likely to be diagnosed with the chronic condition characterized by insufficient insulin production.
“We found that blue-eyed patients have around a 50% higher chance of having type 1 diabetes compared to brown-eyed individuals from the same geographic area and ethnic background,” explains lead investigator Dr. Amanda Wong from the University of California, San Francisco’s Center for Autoimmune Disease Research. “This suggests that iris color may provide clues about genetic factors underlying the disease.”
Wong’s team examined medical data from over 580 adults spanning two regions of Italy. They compared 286 Caucasian patients who were treated for type 1 diabetes against a healthy control group of 297 people with no history of the illness.
Individuals categorized as having blue/gray, green/hazel, or light brown eyes made up over 74% of those diagnosed with type 1 diabetes. Comparatively, under 53% of the participants without the condition had similar light eye colors.
“Our data points to blue eye color being an independent risk marker for developing this form of diabetes,” says Wong. “We’re conducting more studies focused on how exactly iris pigmentation and autoimmune pathology are connected on a cellular level.”
The researchers speculate that the link may have something to do with tyrosinase, a gene that controls melanin production and eye color, but is also involved in triggering autoimmune reactions. Additional genetic studies are underway to investigate this further.
“If confirmed, a gene associated with blue eyes could open doors for preventive screening in those genetically predisposed,” notes endocrinologist Dr. Neil Lieberman, who was not part of the study. “We may be able to target at-risk groups for early intervention or lifestyle changes aimed at delaying disease progression.”
Wong agrees further research is still needed but stresses that her team’s findings should not cause alarm, as most people with light irises will not acquire type 1 diabetes. However, for Caucasians who do get diagnosed, eye color may provide some clues into the hereditary culprits behind their β-cell dysfunction.
“We hope our iris color transcription studies will reveal predictive biomarkers that can be used for early detection and treatments focused on the root pathology of diabetes,” adds Wong. “The applications could be life-changing for those genetically prone to developing this chronic condition.”
Until more definitive preventions come about, Wong recommends residents concerned about type 1 diabetes risk focus on maintaining a body weight appropriate for their height through regular exercise and a balanced, low glycemic diet. She also stresses the importance of adequate sleep and vitamin D from sun exposure or supplementation.