The Relation of Arterial Structure and Function to the Progression of AMD: the CHARM Study

Abstract

Abstract: : Purpose: To examine the relationship of measures of carotid atherosclerosis and arterial function with the progression of AMD. Methods: People with any age–related maculopathy were recruited from the population–based Melbourne Visual Impairment Project and the VECAT study, a non–significant clinical trial of antioxidants to prevent the progression of AMD and cataracts. Three measures of intima–media thickness (IMT), a measure of atherosclerosis in the carotid artery, were obtained: mean maximum IMT, average of 6 measurements on the far wall, and average of 12 measurements. Systemic arterial compliance (SAC), augmentation index (AI) and pulse wave velocity were also measured. Increased pulse wave velocity is indicative of stiffer arteries. Progression of ARM was defined as an increase in one or more ARM steps in either eye by the International Grading Scheme for AMD. All statistical models included age, ‘ever smoked cigarettes’ and family history of AMD. The SAC and AI models included height and heart rate, and the pulse wave velocity model included blood pressure. Results: The 254 participants ranged in age from 51 to 89 years and 119 (46.9%) were male. The odds of AMD progression in the upper quintile relative to the lower quintile was 0.28 for AI (95%CL=0.10, 0.75), 1.96 (95%CL=0.63, 6.08) for pulse wave velocity, 1.96 (95%CL=0.74, 5.16) for SAC, 1.52 (95%CL=0.57, 4.07) for the 6 far wall measurements, 1.57 (95%CL=0.57, 4.29) for the average of 12 IMT measurements, and 1.59 (95%CL=0.58, 4.36) for the mean maximum IMT measurement. Conclusions: These progression data provide some support of previous cross–sectional findings of a significant relationship between carotid atherosclerosis and prevalent AMD, although the current findings were not statistically significant due to the relatively small number of progression cases. The counter–intuitive finding of an inverse association between artery stiffness and AMD progression needs further investigation. Taken with several reports of a potential protective effect of statins or antihypertensive agents in the development and progression of AMD, these data support the need for further research regarding the link between heart disease and AMD, with pilot studies to determine if prevention of heart disease and its risk factors may also help to prevent progression of AMD.

Keywords: age–related macular degeneration • clinical (human) or epidemiologic studies: risk factor assessment