Common Blood Test Can Show AMD Risk

February 18, 2013

Researchers have determined that a common blood test for assessing cardiovascular disease risk can also indicate risk for age-related macular degeneration (AMD). They found that people with high levels of high-sensitivity C-reactive protein (hsCRP) — a biomarker for inflammation related to heart disease, cancer and other conditions — have a 49 percent greater risk of all forms of AMD compared to those with low levels of hsCRP. High levels of hsCRP are also associated with an 84 percent increased for wet AMD, the form of disease more likely to cause severe vision loss. Results of the study were published online in JAMA Ophthalmology.

While inflammation is part of the body’s attempt to heal itself from disease and injury, chronic inflammation has been linked to heart disease, diabetes, cancer and autoimmune conditions. Over the past decade, retinal researchers, including those funded by the Foundation Fighting Blindness, have found that chronic inflammation plays a key role in AMD.

The most notable advancement in this area of research occurred in 2005, when scientists discovered that variations in Complement factor H, a gene linked to the immune system and inflammatory processes, affected AMD risk. Since that finding, additional immune-system genes have been linked to AMD.

“A retinal exam from an eye doctor is by far the best way to determine risk for AMD. People over 50 need to get their eyes checked regularly for signs of macular degeneration and other ophthalmological conditions related to aging,” says Dr. Stephen Rose, the Foundation’s chief research officer. “However, if someone gets a blood test that shows high levels of high-sensitivity CRP, that should raise a red flag. Hopefully, it will motivate them to be vigilant about getting their eyes checked as well as giving up smoking and other unhealthy habits that increase risk for both heart disease and AMD.”

The research team investigating hsCRP level and AMD risk included scientists from Harvard, Johns Hopkins University and the University of Utah. They evaluated blood samples from approximately 2,000 participants from five previous cancer and heart disease studies.