Ambient air pollution associations with retinal morphology in the UK Biobank

PURPOSE. Because air pollution has been linked to glaucoma and AMD, we characterized the relationship between pollution and retinal structure. METHODS. We examined data from 51,710 UK Biobank participants aged 40 to 69 years old. Ambient air pollution measures included particulates and nitrogen oxides. SD-OCT imaging measured seven retinal layers: retinal nerve fiber layer, ganglion cell–inner plexiform layer, inner nuclear layer, outer plexiform layer + outer nuclear layer, photoreceptor inner segments, photoreceptor outer segments, and RPE. Multivariable regression was used to evaluate associations between pollutants (per interquartile range increase) and retinal thickness, adjusting for age, sex, race, Townsend deprivation index, body mass index, smoking status, and refractive error. RESULTS. Participants exposed to greater particulate matter with an aerodynamic diameter of <2.5 μm (PM_2.5) and higher nitrogen oxides were more likely to have thicker retinal nerve fiber layer (β = 0.28 μm; 95% CI, 0.22–0.34; P = 3.3 × 10⁻²⁰ and β = 0.09 μm; 95% CI, 0.04–0.14; P = 2.4 × 10⁻⁴, respectively), and thinner ganglion cell–inner plexiform layer, inner nuclear layer, and outer plexiform layer + outer nuclear layer thicknesses (P < 0.001). Participants resident in areas of higher levels of PM_2.5 absorbance were more likely to have thinner retinal nerve fiber layer, inner nuclear layer, and outer plexiform layer + outer nuclear layers (β = –0.16 [95% CI, –0.22 to –0.10; P = 5.7 × 10⁻⁸]; β = –0.09 [95% CI, –0.12 to –0.06; P = 2.2 × 10⁻¹²]; and β = –0.12 [95% CI, –0.19 to –0.05; P = 8.3 × 10⁻⁴], respectively). CONCLUSIONS. Greater exposure to PM_2.5, PM_2.5 absorbance, and nitrogen oxides were all associated with apparently adverse retinal structural features.