Grant Abstract: Macular Pigment in Aging and Disease

Grant Number: 1R01EY025292-01
PI Name: Mares
Project Title: Macular Pigment in Aging and Disease

Abstract: There are a growing number of adults supplementing with lutein (L) and zeaxanthin (Z) for eye health, supported by an increasing body of scientific evidence suggesting that these carotenoids protect against age related eye disease and improve visual performance. Yet, data is lacking about the levels of intake needed for optimal benefit and safety. The first available evidence for levels of L and Z in the retina and eye associated with reduced incidence and progression of age-related macular degeneration (AMD) and loss in visual acuity associated with the loss of cone photoreceptor function will be obtained in 2015-2017, as part of the Macular Pigment in Aging and Disease Study (NIH EY025292), in survivors of the Carotenoids in Age-Related Eye Disease Study (CAREDS) in 2001-2004, in 2,004 older women, 53 to 84 years of age. Two time sensitive additions to follow-up study visits are proposed to enhance the scientific gains of this study about the levels of L and Z which promote optimal eye health, at added low cost.

Aim one is to add a measure of dark adaptation speed, providing the first opportunity to determine the relationships between the levels of lutein in the diet and retina subsequent rod function. Abnormalities in dark adaptation are more common and better correlate with self-reported difficulty in performing vision related tasks in dim lights than measures of visual acuity, involving cones. Dark adaptation speed will be collected in a subsample of 688 women, providing the first assessment of lutein and zeaxanthin levels in the retina and in the diet (from foods and supplements), in relation to the speed of dark adaptation more than a decade later. We hypothesize that higher levels will protect against damage to the retina which would otherwise compromise the function of rod photoreceptors, leading to slow dark adaptation speeds.

Aim two is to collect saliva specimens for future genotyping. This will enable future studies of genotypes which modify the optimal levels of L and Z in the retina and diet, consistent with optimal retinal health. Saliva specimens will be collected in all women in visits across all study sites (n=1043) and by mail in an additional 196 women who cannot attend in-person study visits. The availability of saliva specimens will enable future genome wide studies in this cohort to identify new and unknown variants in genes for proteins associated with low ability to absorb, transport and stabilize these pigments in the retina, and for genes which confer risk for age-related macular degeneration. These can then be studied as modifiers of relationships of L and Z in the diet to levels in the retina, and of both predictors to eye outcomes. Thus, studies resulting from these two aims are expected to advance knowledge of levels of L and Z intake that are both beneficial and safe.

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