Dietary Zinc Intake is Associated with Key Clinical Outcomes in Neovascular Age-Related Macular Degeneration Patients

Abstract

Purpose : Antioxidant and zinc consumption as well as a dietary pattern high in fruits, vegetables and fish have been shown to reduce progression from early to late age-related macular degeneration (AMD). However, there is little evidence on the associations between these dietary factors and key clinical outcomes in patients diagnosed and treated for neovascular AMD (nAMD) with anti-vascular endothelial growth factor (VEGF) therapy. This cross-sectional study tested the hypothesis that a dietary intake high in antioxidants and zinc, fruits, vegetables and fish is associated with more favourable clinical outcomes including reduced presence of fluid, mean central macular thickness (CMT), number of anti-VEGF injections and better visual acuity, in a large clinic-based cohort of treated nAMD patients.

Methods : 547 patients with nAMD were recruited from a clinic (Sydney West Retina) in Sydney during 2012-2015. Presence of nAMD was diagnosed using fluorescein angiography. Dietary intakes were determined using a validated food frequency questionnaire (FFQ). Presence of intra-retinal and sub-retinal fluid (IRF, SRF), pigment epithelial detachment (PED) and CMT were recorded from OCT images. Visual acuity was recorded from clinical notes. Linear and logistic regression analysis was used to determine associations.

Results : Threshold analysis of the entire cohort revealed that participants with daily zinc intake below (n=91) versus above (n=333) 8.1 mg had greater odds of presence of SRF, multivariable-adjusted OR 0.56 (95%CI 0.36-0.96). This association was stronger amongst persons who had at least 6 months of therapy, OR 0.32 (95%CI 0.14-0.75). In the entire cohort, participants in the lowest or first quartile compared to those in the upper 3 quartiles of zinc intake combined had significantly greater mean CMT (254.81µm versus 232.15µm, respectively, multivariable-adjusted p=0.03). Other dietary parameters were not significantly associated with clinical outcomes in nAMD patients.

Conclusions : Decreased dietary consumption of zinc was found to be significantly associated with presence of sub-retinal fluid and increased macular thickness in treated eyes with nAMD. These findings suggest that increasing dietary zinc intake in patients with nAMD undergoing anti-VEGF therapy, could beneficially influence their clinical outcomes.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.