Association of Ambient Air Pollution Exposure With Incident Glaucoma: 12-Year Evidence From the UK Biobank Cohort

Abstract

Purpose: Glaucoma is the leading cause of irreversible blindness worldwide. Despite growing concerns about air quality and its impact on ocular health, there remains a knowledge gap regarding the long-term association between air pollution and glaucoma risk. This study investigates the relationship between exposure to ambient air pollution and incidence of glaucoma.

Methods: In this prospective study, we used land use regression models to estimate levels of various air pollutants, including fine particulate matter (PM2.5), PM2.5 absorbance, PM2.5-10, PM10, nitrogen dioxide (NO2), and nitrogen oxides (NOx). Incidents of glaucoma were ascertained through routinely collected hospital admission records. Multivariate Cox proportional hazards models were used to examine the associations between air pollution exposure and glaucoma incidence, adjusting for potential confounding sociodemographic, physical, and lifestyle factors.

Results: Data from 481,113 participants were included. Over a median follow-up of 12.8 years, 9224 incident cases of glaucoma were identified. In the maximally adjusted model, per interquartile range increase in PM2.5 was associated with a 3% greater risk of developing glaucoma (hazard ratio [HR] = 1.03, 95% confidence interval [CI] = 1.00 to 1.06, P = 0.048). Participants in the highest quartile had a 10% increased risk of developing glaucoma compared to those in the lowest quartile (HR = 1.10, 95% CI = 1.03 to 1.17, P = 0.005).

Conclusions: Higher levels of exposure to ambient air pollutants, particularly PM2.5, are associated with an increased risk of developing glaucoma. These results highlight the potential public health impact of ambient air pollution on glaucoma risk and underscore the urgent need for further research into targeted environmental interventions in this domain.

Figure 1.

Flow diagram. The baseline for the study is established at the time when the air pollution levels were estimated, specifically in the year 2010. Accordingly, any events that occurred before December 31, 2010, were excluded. ICD, International Classification of Diseases; IOP, intraocular pressure; NO₂, nitrogen dioxide; NO_x, nitric oxides.

Figure 2.

Visual Representation of adjusted HRs across quartiles of air pollution exposure. HRs have been derived from a maximally adjusted model (refer to Table 2 and Table 3, model B) that incorporates age, sex, ethnicity, Townsend deprivation index, body mass index, and smoking status as covariates. On the Y-axis, the HRs are presented on a log scale via a natural logarithm transformation (base e). A horizontal dashed gray line denotes the no-effect threshold, corresponding to an HR of 1. Error bars indicate 95% confidence intervals. Asterisks highlight statistically significant differences, with * indicating P < 0.05, and ** indicating P < 0.01. PM, particulate matter; NO₂, nitrogen dioxide; NO_x, nitrogen oxides; HR, hazard ratio. Definitions for particulate matter include: PM_2.5, finer particles with a diameter of less than 2.5 µm; PM_{2.5 absorbance}, a measure of the light absorption (blackness) of PM_2.5 filters, serving as a proxy for elemental carbon typically emitted from combustion sources; PM_2.5-10, coarse particulate fraction between 2.5 µm and 10 µm in diameter; PM₁₀, particles with a diameter of 10 µm or less.