Using data from the Chinese American Eye Study, investigators have found that Chinese Americans have higher rates of AMD and lower rates of diabetic retinopathy (DR) when compared to Chinese populations residing in China, suggesting the influence of environmental or behavioral factors.
"This study sounds a clarion call for all eye care providers to be aware of the prevalence of wet AMD in those of Chinese ancestry and to provide the available treatments such as injections and laser therapies," said Rohit Varma, MD, MPH, director of the University of Southern California Roski Eye Institute and the study's lead investigator. "And while not as prevalent as we see in the Latino community, we also need to be aware of addressing those Chinese Americans with diabetes to prevent DR and the onset of significant visual impairment."
This National Eye Institute-funded study is the largest, most comprehensive population-based study of eye disease among U.S. adults of Chinese ancestry to date. All 4,582 participants were age 50 or older living in Monterey Park, California and compromised of mostly first-generation immigrants (98%). Rather than relying on self-reporting, subjects underwent an interview as well as comprehensive clinical and eye examinations, including detailed retinal photography of both eyes.
In the AMD analysis, an estimated 7.8% of Chinese Americans exhibited signs of early AMD, while 0.4% showed signs of late AMD, after accounting for age. Although these rates are lower than the reported rates in non-Chinese ethnic groups, they are higher than the rates reported in studies of Chinese populations living in urban or rural China.
Of the 14 cases of advanced AMD, 85.7% had wet AMD and 14.3% had geographic atrophy. This ratio was almost identical to that found in Latino individuals from Los Angeles Latino Eye Study (LALES), but is almost the opposite of what has been found in other ethnic groups. It remains to be elucidated if the lower than average AMD rates are due to ethnic differences or dietary factors,
In a separate analysis of the same data, study authors found that the age-standardized prevalence of DR was lower compared with that in Chinese residents in rural northern China (41% vs. 45.7%) and lower than Latinos in the LALES study (48.1%). Additionally, participants with diabetes were 3 times more likely than those without the disease to have significant visual impairment.
"The study gives us unprecedented insights into the burden of eye disorders among this fast growing racial group in the U.S. The findings will help inform preventive screening strategies and guide health care resource planning," said Maryann Redford, DDS, MPH, a program director for Collaborative Clinical Research at the National Eye Institute.
These two population papers are important to identify the prevalence of DR and ARMD in an ethnic population in greater Los Angeles. This is a continued effort on the authors’ part after their population-based study of Latinos.