The new report in the Archives of Ophthalmology finds that 6.5% of middle-aged and older adults in the U.S. had signs of the eye disease in 2005-2008. Non-Hispanic blacks aged 60 and older had lower rates of macular degeneration than non-Hispanic whites of the same age.
The findings are a stark contrast to an earlier NHANES analysis from 1998 to1994, which estimated that AMD developed in 9.4% of Americans.
Study authors say lower rates of smoking, improved blood pressure management, use of anti-oxidants vitamins and an increase in healthier diets and exercise programs may have contributed to the decline in AMD among older adults. The number of Americans with macular degeneration fell 30 percent in about two decades, the study found. The findings were unexpected, as previous work suggested the aging population would drive up rates of the condition.