C-Reactive protein levels and the Outer retina in a large cohort study: UK Biobank

Abstract

Purpose : C-reactive protein (CRP) level is elevated in inflammatory conditions and raised CRP is associated with age-related macular degeneration (AMD). AMD affects both the photoreceptors and retinal pigment epithelium (RPE). Our study aimed to examine the relationship between CRP and outer retinal sub-layer thicknesses.

Methods : UK Biobank participants aged 40 to 69 years old completed a detailed baseline questionnaire and underwent ophthalmic assessment. Spectral-domain optical coherence tomography (OCT) provided photoreceptor sub-layer thickness and retinal pigment epithelium (RPE). After excluding participants with ocular conditions, high refractive error and poor OCT image quality, 47,111 participants were included. Multivariate linear regression models were constructed to evaluate associations between CRP (tertile) and retinal thicknesses, adjusting for demographic and ocular factors, and cardiovascular risk factors. The North West Multi-centre Research Ethics Committee approved the study in accordance with the principles of the Declaration of Helsinki.

Results : Compared to the lowest CRP tertile (<1mg/L), participants in the higher CRP tertiles (>3mg/L) had thinner total photoreceptor layer in a dose-dependent manner, respectively: (T2: -0.35; 95% CI -0.51 to -0.19) and (T3: -0.74; 95% CI -0.93 to -0.54) (p for trend <0.001). Similarly, compared to lowest CRP tertile, the highest CRP tertile was associated with thinner photoreceptor sub-layers (photoreceptor synaptic region: β: -0.30; 95% CI -0.46 to -0.14), photoreceptor inner segment: β: -0.07; 95% CI -0.11 to -0.02 and photoreceptor outer segment: β: -0.37; 95% CI -0.48 to -0.26) (p for trend <0.001 for all photoreceptor sub-layers). Additionally, the highest CRP tertile was associated with thinner RPE (β: -0.13; 95% CI -0.23 to -0.03) compared to the lowest tertile.

Conclusions : Higher serum CRP, a marker of inflammation was associated with thinner total photoreceptor layer and RPE. These results strengthen the evidence for the role of inflammation in the pathogenesis of AMD.

This is a 2020 ARVO Annual Meeting abstract.