Age-Related Macular Degeneration and Risk for Stroke

Age-Related Macular Degeneration and Risk for Stroke

Tien Yin Wong, MD, MPH, PhD;
Ronald Klein, MD, MPH;
Cong Sun, MD, MPH;
Paul Mitchell, MD, PhD;
David J. Couper, PhD;
Hong Lai, PhD;
Larry D. Hubbard, MAT;
A. Richey Sharrett, MD, DrPH; and
for the Atherosclerosis Risk in Communities Study

From University of Melbourne, Victoria, Australia; University of Wisconsin, Madison, Wisconsin; University of Sydney, Sydney, Australia; University of North Carolina, Chapel Hill, North Carolina; and Johns Hopkins University, Baltimore, Maryland.

Abstract

Background: Age-related macular degeneration (AMD) affects 7 million persons 40 years of age and older in the United States. Risk factors for the disease are similar to those for stroke.

Objective: To determine what relationship, if any, exists between AMD and incident clinical stroke.

Design: Prospective cohort study.

Setting: The population-based Atherosclerosis Risk in Communities Study, which was conducted in Minnesota, Maryland, Mississippi, and North Carolina.

Patients: 10 405 persons between 49 and 73 years of age who had no history of stroke or coronary heart disease.

Measurements: Participants had retinal photographs taken between 1993 and 1995. A standardized protocol was used to evaluate the photographs for the presence of drusen and other signs of AMD. Incident stroke events were identified and validated by reviewing case records.

Results: There were 498 early-stage and 10 late-stage cases of AMD in the cohort (n = 508). Over a 10-year period, 241 persons had an incident stroke event. After adjusting for age, sex, ethnicity, and site, the authors found that persons with early-stage AMD had a higher cumulative incidence of stroke than those without the disease (4.08% vs. 2.14%). The presence of early-stage AMD was associated with a higher adjusted risk for stroke (hazard ratio, 1.87 [95% CI, 1.21 to 2.88]). Further adjustment for systolic blood pressure, diabetes, cigarette smoking, and use of antihypertensive medications did not substantially alter this association (hazard ratio, 1.85 [CI, 1.19 to 2.87]). The authors found that the association between early-stage AMD and stroke varied by study site and patient ethnicity. Multivariable-adjusted hazard ratios were 3.15 and 1.07 in samples of white patients in Minnesota and Maryland, respectively; 3.77 in a sample of African-American patients in Mississippi; and 0.33 in a sample of mostly white patients (91%) in North Carolina. No site included sufficient numbers of both African-American and white patients to determine whether ethnicity contributed to the observed differences by study site.

Limitations: There were few cases of late-stage AMD, and the cohort assembly method prohibited full understanding of variation by ethnicity and site.

Conclusion: Middle-aged persons with signs of early-stage AMD have a higher risk for stroke independent of traditional stroke risk factors.

Article and Author Information

Acknowledgments: The authors thank the staff and participants of the Atherosclerosis Risk in Communities Study for their important contributions.
Potential Conflicts of Interest: None disclosed.
Grant Support: By National Heart, Lung, and Blood Institute contracts N01-HC-55015, N01-HC-55016, N01-HC-55018, N01-HC-55019, N01-HC-55020, N01-HC-55021, and N01-HC-55022. Additional support was provided by a Science Technology Innovation Grant from the State of Victoria. Dr. Wong was supported by a Clinical Investigator Award from the Sylvia and Charles Viertel Charitable Foundation.
Requests for Single Reprints: Tien Yin Wong, MD, MPH, PhD, Centre for Eye Research Australia, University of Melbourne, 32 Gisborne Street, East Melbourne 3002, Australia; e-mail, twong{at}unimelb.edu.au.
Current Author Addresses: Dr. Wong: Centre for Eye Research Australia, University of Melbourne, 32 Gisborne Street, East Melbourne 3002, Australia, and Singapore Eye Research Institute, National University of Singapore, 11 Third Hospital Avenue, Singapore.
Dr. Sun: Centre for Eye Research Australia, University of Melbourne, Australia.
Dr. Klein: Department of Ophthalmology, University of Wisconsin, 610 North Walnut Street, 4th Floor, Madison, WI 53726.
Dr. Mitchell: Department of Ophthalmology, University of Sydney, New South Wales 2006, Australia.
Dr. Couper: Department of Biostatistics, 137 East Franklin Street, Suite 203, Chapel Hill, NC 27599.
Dr. Lai: Wilmer Ophthalmological Institute, 600 North Wolfe Street, Johns Hopkins University, Baltimore, MD 21287.
Mr. Hubbard: Department of Ophthalmology, University of Wisconsin, 406 Science Drive, Suite 400, Madison, WI 53705.
Dr. Sharrett: Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205.
Author Contributions: Conception and design: T.Y. Wong, P. Mitchell, L.D. Hubbard, A.R. Sharrett.
Analysis and interpretation of the data: C. Sun, L.D. Hubbard, A.R. Sharrett.
Critical revision of the article for important intellectual content: T.Y. Wong, R. Klein, P. Mitchell, H. Lai, L.D. Hubbard, A.R. Sharrett.
Final approval of the article: T.Y. Wong, R. Klein, C. Sun, P. Mitchell, D.J. Couper, L.D. Hubbard.
Provision of study materials or patients: L.D. Hubbard.
Statistical expertise: D.J. Couper, H. Lai.
Obtaining of funding: L.D. Hubbard.
Administrative, technical, or logistic support: T.Y. Wong, L.D. Hubbard.
Collection and assembly of data: D.J. Couper, L.D. Hubbard.