AMD Prevalence Appears to Decline

An estimated 6.5% of Americans aged 40 and older have age-related macular degeneration, according to data from the 2005-2008 National Health and Nutrition Evaluation Survey, or NHANES, reported in the January issue of Archives of Ophthalmology. This represented a decrease from the 9.4% reported in the 1988-1994 Third National Health and Nutrition Examination Survey (NHANES III) – the last nationally representative estimates of the prevalence of AMD.

In the latest research, Dr. Ronald Klein of University of Wisconsin, Madison, and colleagues analyzed data from 6,797 participants who had full medical exams at a NHANES unit. They also analyzed digital images for signs of AMD, including drusen, increased retinal pigment, retinal pigment epithelial depigmentation, geographic atrophy, and signs of exudative AMD (Arch. Ophthalmol. 2011;129:75-80).

After excluding 1,244 individuals who were not photographed or who had ungradable fundus images, the researchers estimated the total prevalence of AMD in the U.S. civilian noninstitutionalized population to be 6.5%, which is 30.8% lower than reported in the 1988-1994 cohort. The estimated prevalence of late (more advanced) AMD was 0.8%. Non-Hispanic black individuals aged 60 and older had a statistically significant lower prevalence of any AMD than did non-Hispanic white individuals of the same age – a finding consistent with NHANES III.

"These estimates are consistent with a decreasing incidence of AMD reported in another population-based study and have important public health implications," the authors said. "The decreasing prevalence of AMD may reflect recent change in the frequency of smoking and other exposures such as diet, physical activity, and blood pressure associated with AMD. It remains to be seen whether public health programs designed to increase awareness of the relationships of these exposures to AMD in patients at risk and their physicians and eye care providers will continue to result in further decline of the prevalence of AMD in the population."

Also, Mexican-American individuals appeared to have similar frequencies of early AMD but lower frequencies of late AMD, the researchers found. "The reasons for racial/ethnic differences may reflect differences in environmental or host exposures (e.g., smoking, physical activity, diet) and genetic differences in distributions of protective and high-risk genes associated with AMD among the different racial/ethnic groups.

The researchers say this study has several strengths, namely its nationwide, multiracial, population-based sample, and objective system for grading fundus photographs. Still, they urge caution when interpreting results because several factors may have led them to underestimate the prevalence of AMD. Specifically, the study did not include an institutionalized population, such as nursing home patients; significant numbers of eligible patients did not have photographs; and researchers excluded patients who had no light perception or only light perception in both eyes.

The researchers reported no disclosures. This research was supported by a National Health and Nutrition Examination Survey contract, which provided funding for the entire study, including collection and analysis of data. Additional support was provided by Senior Scientific Investigator Awards from Research to Prevent Blindness.

An estimated 6.5% of Americans aged 40 and older have age-related macular degeneration, according to data from the 2005-2008 National Health and Nutrition Evaluation Survey, or NHANES, reported in the January issue of Archives of Ophthalmology. This represented a decrease from the 9.4% reported in the 1988-1994 Third National Health and Nutrition Examination Survey (NHANES III) – the last nationally representative estimates of the prevalence of AMD.

In the latest research, Dr. Ronald Klein of University of Wisconsin, Madison, and colleagues analyzed data from 6,797 participants who had full medical exams at a NHANES unit. They also analyzed digital images for signs of AMD, including drusen, increased retinal pigment, retinal pigment epithelial depigmentation, geographic atrophy, and signs of exudative AMD (Arch. Ophthalmol. 2011;129:75-80).

After excluding 1,244 individuals who were not photographed or who had ungradable fundus images, the researchers estimated the total prevalence of AMD in the U.S. civilian noninstitutionalized population to be 6.5%, which is 30.8% lower than reported in the 1988-1994 cohort. The estimated prevalence of late (more advanced) AMD was 0.8%. Non-Hispanic black individuals aged 60 and older had a statistically significant lower prevalence of any AMD than did non-Hispanic white individuals of the same age – a finding consistent with NHANES III.

"These estimates are consistent with a decreasing incidence of AMD reported in another population-based study and have important public health implications," the authors said. "The decreasing prevalence of AMD may reflect recent change in the frequency of smoking and other exposures such as diet, physical activity, and blood pressure associated with AMD. It remains to be seen whether public health programs designed to increase awareness of the relationships of these exposures to AMD in patients at risk and their physicians and eye care providers will continue to result in further decline of the prevalence of AMD in the population."

Also, Mexican-American individuals appeared to have similar frequencies of early AMD but lower frequencies of late AMD, the researchers found. "The reasons for racial/ethnic differences may reflect differences in environmental or host exposures (e.g., smoking, physical activity, diet) and genetic differences in distributions of protective and high-risk genes associated with AMD among the different racial/ethnic groups.

The researchers say this study has several strengths, namely its nationwide, multiracial, population-based sample, and objective system for grading fundus photographs. Still, they urge caution when interpreting results because several factors may have led them to underestimate the prevalence of AMD. Specifically, the study did not include an institutionalized population, such as nursing home patients; significant numbers of eligible patients did not have photographs; and researchers excluded patients who had no light perception or only light perception in both eyes.

The researchers reported no disclosures. This research was supported by a National Health and Nutrition Examination Survey contract, which provided funding for the entire study, including collection and analysis of data. Additional support was provided by Senior Scientific Investigator Awards from Research to Prevent Blindness.

An estimated 6.5% of Americans aged 40 and older have age-related macular degeneration, according to data from the 2005-2008 National Health and Nutrition Evaluation Survey, or NHANES, reported in the January issue of Archives of Ophthalmology. This represented a decrease from the 9.4% reported in the 1988-1994 Third National Health and Nutrition Examination Survey (NHANES III) – the last nationally representative estimates of the prevalence of AMD.

In the latest research, Dr. Ronald Klein of University of Wisconsin, Madison, and colleagues analyzed data from 6,797 participants who had full medical exams at a NHANES unit. They also analyzed digital images for signs of AMD, including drusen, increased retinal pigment, retinal pigment epithelial depigmentation, geographic atrophy, and signs of exudative AMD (Arch. Ophthalmol. 2011;129:75-80).

After excluding 1,244 individuals who were not photographed or who had ungradable fundus images, the researchers estimated the total prevalence of AMD in the U.S. civilian noninstitutionalized population to be 6.5%, which is 30.8% lower than reported in the 1988-1994 cohort. The estimated prevalence of late (more advanced) AMD was 0.8%. Non-Hispanic black individuals aged 60 and older had a statistically significant lower prevalence of any AMD than did non-Hispanic white individuals of the same age – a finding consistent with NHANES III.

"These estimates are consistent with a decreasing incidence of AMD reported in another population-based study and have important public health implications," the authors said. "The decreasing prevalence of AMD may reflect recent change in the frequency of smoking and other exposures such as diet, physical activity, and blood pressure associated with AMD. It remains to be seen whether public health programs designed to increase awareness of the relationships of these exposures to AMD in patients at risk and their physicians and eye care providers will continue to result in further decline of the prevalence of AMD in the population."

Also, Mexican-American individuals appeared to have similar frequencies of early AMD but lower frequencies of late AMD, the researchers found. "The reasons for racial/ethnic differences may reflect differences in environmental or host exposures (e.g., smoking, physical activity, diet) and genetic differences in distributions of protective and high-risk genes associated with AMD among the different racial/ethnic groups.

The researchers say this study has several strengths, namely its nationwide, multiracial, population-based sample, and objective system for grading fundus photographs. Still, they urge caution when interpreting results because several factors may have led them to underestimate the prevalence of AMD. Specifically, the study did not include an institutionalized population, such as nursing home patients; significant numbers of eligible patients did not have photographs; and researchers excluded patients who had no light perception or only light perception in both eyes.

The researchers reported no disclosures. This research was supported by a National Health and Nutrition Examination Survey contract, which provided funding for the entire study, including collection and analysis of data. Additional support was provided by Senior Scientific Investigator Awards from Research to Prevent Blindness.