Diabetic Retinopathy Prevalence Rising

ATLANTADiabetic retinopathy is the leading cause of new cases of legal blindness in U.S. adults, and costs the country approximately $500 million annually. In a new study (JAMA. 2010;304(6):649-56), researchers from the Centers for Disease Control and Prevention (CDC) examined the prevalence and risk factors for diabetic retinopathy in U.S. adults age 40 and older, using data from the National Health and Nutrition Examination Survey (NHANES), 2005-2008.

Xinzhi Zhang, M.D., Ph.D., and colleagues examined data on 1,006 individuals, and found estimated prevalence of diabetic retinopathy and vision-threatening diabetic retinopathy was 28.5 percent and 4.4 percent, respectively. Incidence of retinopathy was higher among men (31.6 percent of males in the sample), non-Hispanic blacks (38.8 percent) and Mexican Americans (34.0 percent) with diabetes. Independent risk factors for diabetic retinopathy included higher hemoglobin A1c levels, duration of diabetes, use of insulin and higher systolic blood pressure.

The research team noted with the aging population, increasing proportion of the population with mixed racial/ethnic heritage and the continued rise in incidence of diabetes, it is likely the number of cases of diabetic retinopathy will increase. They suggested, the need for eye care and for culturally appropriate interventions that can reduce disparity and improve access to eye care among diverse populations is also likely to increase," and hoped the estimates would help in the planning of eye care services for the U.S. population.

Vision loss due to diabetic retinopathy occurs through mechanisms including retinal detachment, hemorrhage, neovascular glaucoma or capillary nonperfusion. Nutritional studies have suggested antioxidants such as vitamins E and C, resveratrol and other polyphenols may help stave off development of retinopathy and strengthen capillaries. One recent trial on French maritime pine bark extract (as Pycnogenol, from Horphag Research) found adults with early diabetic retinopathy who took the extract for three months had improved visual acuity, which the researchers suggested was caused by enhanced retinal blood circulation reducing edema (J Ocul Pharmacol Ther. 2009 Dec;25(6):537-40).