Purpose
Previous studies have utilized subjective self-reported measures of physical activity to provide conflicting reports on the association between physical activity and age-related macular degeneration. We aim to utilize physical activity data measured objectively via accelerometry by a U.S. nationally representative population-based survey in order to assess the associations between age-related macular degeneration (AMD) and behavioral parameters such as physical activity.
Methods
A population-based cross-sectional study of the U.S. population, the 2005-2006 National Health and Nutrition Examination Surveys provided demographic, behavioral, and medical data to identify potential behavioral risk factors for AMD. Retinal images from an ophthalmic examination were graded with a standardized protocol to provide the status of AMD for patients over the age of 40. Physical activity was objectively measured using data from an accelerometer worn by patients for 7 consecutive days. Univariate and multivariate analyses were conducted to assess the significance of these risk factors for AMD.
Results
Of the 2,413 participants with graded retinal images, 193 patients (8.00%) had AMD with 166 patients (6.88%) presenting early AMD and 27 patients (1.12%) presenting late AMD. Age, ethnicity, body mass index (BMI), triglycerides, high blood pressure, physical activity, smoking history, family income, education, and cardiovascular disease [including history of myocardial infraction, stroke, congestive heart failure, coronary heart disease, and angina] were all significant (p<0.05) during mutivariate analysis of risk factors for AMD.
Conclusions
This study utilized objectively measured accelerometer data to suggest that physical activity has a protective effect against AMD. Other findings from this 2005-2006 NHANES data were consistent with current literature identifying risk factors for AMD in the US population.