Early Age-Related Macular Degeneration Linked to Modifiable Risk Factors

Laurie Barclay, MD

June 16, 2010

June 16, 2010 — Early age-related macular degeneration (AMD) is linked to modifiable risk factors, according to the results of a study reported in the June issue of Archives of Ophthalmology.

"To our knowledge, accurate estimates of prevalence of AMD among adults younger than 40 years are lacking," write Ronald Klein, MD, MPH, from the University of Wisconsin, Madison, and colleagues. "Such information is important for understanding the relationships of risk factors to AMD across the age spectrum and for identifying factors that might affect this disease earlier in life. The purposes of this report are to describe the prevalence of AMD and its defining lesions and their relationship to age, sex, and other factors in the large Beaver Dam Offspring Study (BOSS) cohort."

Using the Wisconsin Age-Related Maculopathy Grading System to grade digital color fundus images, the investigators determined the presence and severity of various characteristics of drusen and other lesions typical of AMD in 2810 participants aged 21 to 84 years in the Beaver Dam Offspring Study cohort.

Overall, 3.4% of the cohort had early AMD. Prevalence ranged from 2.4% in participants aged 21 to 34 years to 9.8% in participants 65 years or older. Factors associated with early AMD were identified with a multivariable model. These were age (odds ratio [OR] per age 5 years, 1.22; 95% confidence interval [CI], 1.09 - 1.36), male sex (OR, 1.65; 95% CI, 1.01 - 2.69), more pack-years of cigarettes smoked (1 - 10 vs 0, OR, 1.31; 95% CI, 0.75 - 2.29; ≥11 vs 0, OR, 1.67; 95% CI, 1.03 - 2.73), higher serum high-density lipoprotein cholesterol level (per 5 mg/dL, OR, 0.91; 95% CI, 0.83 - 0.998), and hearing impairment (OR, 2.28; 95% CI, 1.41 - 3.71).

Early AMD was not associated with blood pressure level, body mass index, physical activity level, history of heavy alcohol intake, white blood cell count, hematocrit level, platelet count, serum total cholesterol level, or carotid intimal-medial thickness.

"These data indicate that early AMD is infrequent before age 55 years but increases with age thereafter," the study authors write. "Early AMD is related to modifiable risk factors, e.g., smoking and serum high-density lipoprotein cholesterol level."

Limitations of this study include cross-sectional design, predominantly non-Hispanic white population, low frequency of some risk factors and of the prevalence of early AMD in this middle-aged cohort, and possible uncontrolled confounding.

"The higher frequency of AMD in people aged 65 years or older in an aging American population makes this an important public health problem," the study authors conclude. "Further information regarding the natural history of AMD and its risk factors, especially early in life, is important for developing preventive approaches to it."

The National Institute on Aging, National Eye Institute, National Institute on Deafness and Other Communication Disorders, and National Institutes of Health, and Research to Prevent Blindness supported this study. Dr. Klein has served as a consultant to Pfizer and Genentech.

Arch Ophthalmol. 2010;128:750-758. Abstract