The relationship between ambient air pollution and glaucoma phenotypes in a large community cohort

Abstract

PurposeGlaucoma is reportedly more frequent in people living in urban areas and more than 91% of the world’s population live in areas with air pollution above WHO recommended limits. However, few studies have examined the association between air pollution and risk of glaucoma.MethodsUK Biobank participants aged 40–69 years old completed a detailed baseline questionnaire and underwent ophthalmic and air pollution assessments. Ambient particulate matter with an aerodynamic diameter <2.5 µm (PM2.5) concentration was estimated. Eye measures including self‐reported glaucoma status, corneal compensated intraocular pressure (IOPcc), Goldmann‐correlated intraocular pressure (IOPg) and thickness of retinal layers were collected. Total average thickness of the retinal nerve fibre layer (mRNFL), ganglion cell‐inner plexiform layer (mGC‐IPL), ganglion cell complex (mGCC) and total macular layer were obtained from spectral‐domain optical coherence tomography (SD‐OCT). Multivariable regression models were used to evaluate associations between PM2.5 concentration with self‐reported glaucoma, IOP and retinal layer thickness.ResultsIn multivariable regression analysis, participants resident in areas with higher PM2.5 concentration were more likely to report a diagnosis of glaucoma (OR = 1.13, 95% CI 1.08 to 1.19, per interquartile range [IQR] increase). Higher PM2.5 concentration was associated with thinner mGC‐IPL (β = −0.47 µm, 95% CI −0.56 to −0.39, per IQR increase), mGCC (β = −0.21 µm, 95% CI −0.33 to −0.09, per IQR increase) and total macular thickness (β = ‐0.36 µm, 95% CI −0.56 to −0.15, per IQR increase), while a thicker mRNFL (β = 0.25 µm, 95% CI 0.18 to 0.32, per IQR increase) was observed. There was no relationship between PM2.5 concentration and IOP that was biologically relevant (IOP: β = 0.06 mmHg, 95% CI 0.03 to 0.09, per IQR increase; IOPcc (β = 0.08 mmHg, 95% CI 0.01 to 0.15, highest versus lowest quartile).ConclusionIn this large adult population, higher PM2.5 concentration was associated with a self‐reported diagnosis of glaucoma, and thinner inner retinal layers, consistent with structural changes seen in glaucoma. No biologically relevant relationship was observed for either IOPcc and IOPg. This suggest that PM2.5 concentration may be a potential modifiable risk factor for glaucoma that is independent of IOP.