Researchers led by Johanna M. Seddon, M.D., at the Massachusetts Eye and Ear Infirmary, Harvard Medical School, and Harvard School of Public Health, conducted a prospective longitudinal study to examine several biomarkers for cardiovascular disease, including CRP and IL-6, to measure the relationship between these biomarkers and incidence rates of progression of AMD. They found that higher levels of the systemic inflammatory markers CRP and IL-6 are independently associated with the progression of AMD.
“To our knowledge, this is the first prospective study to report a positive association between the systemic inflammatory markers CRP and IL-6 and the rate of progression to advanced AMD,” the researchers wrote. “Smoking and obesity were significantly related to both CRP and IL-6 levels. Higher values of CRP and IL -6 were found to be significantly related to AMD independent of these biomarkers and other established risk factors.”
The prospective cohort study began in 1989 and included 251 participants aged 60 and older who had some sign of non- exudative AMD and visual acuity of 20/200 or better in at least one eye at baseline. The AMD status was assessed by standardized grading of fundus photographs. Stored fasting blood specimens obtained at baseline were analyzed for levels of the various biomarkers.