# The Association of Muscle-Related Factors With Glaucoma and Related Traits in a Large United Kingdom Population

## TL;DR

This study finds that muscle-related factors like grip strength and thigh muscle volume are linked to higher eye pressure and lower glaucoma risk in men from a large UK population.

## Contribution

The study reveals novel gene-environment interactions and sex-specific associations between muscle traits and glaucoma risk.

## Key findings

- Higher grip strength was associated with thicker retinal layers and higher intraocular pressure in both sexes.
- Stronger grip strength was linked to lower odds of glaucoma in men only.
- Gene-GS interactions showed stronger associations in individuals with higher genetic risk for glaucoma.

## Abstract

The purpose of this study was to investigate the hypothesis that muscle-related factors influence glaucoma risk, we examined the association of grip strength (GS), thigh muscle volume (TMV), and walking pace (WP) with glaucoma and its related traits.

We included UK Biobank participants with data on IOP (N = 114,284), optical coherence tomography (OCT) macular inner retinal layer thickness measures (N = 44,141) and glaucoma status (N = 105,556; 2006–2010). Linear regression was used to evaluate multivariable-adjusted associations of GS, TMV, and WP with IOP and macular inner retinal OCT parameters, and logistic regression was used to evaluate associations with glaucoma status. We additionally examined gene-GS interactions with each outcome using a polygenic risk score (PRS) that combined the effects of 2673 genetic variants associated with glaucoma.

After adjustment for key anthropometric, lifestyle, and medical covariables, we found each additional standard deviation (SD) increase in GS (8.6 kg in men and 6.1 kg in women) was associated with thicker macular retinal nerve fiber layer (mRNFL) by 0.08 µm (P = 0.013) and 0.07 µm (P = 0.010) in men and women, respectively; thicker macular ganglion cell-inner plexiform layer (mGCIPL) by 0.12 µm (P = 0.003) and 0.17 µm (P < 0.001); higher IOP by 0.15 millimeters of mercury (mm Hg; P < 0.001) and 0.16 mm Hg (P < 0.001) and lower odds of glaucoma (odds ratio [OR] = 0.83, P < 0.001) in men only. The association with glaucoma was replicated in the independent EPIC-Norfolk cohort. Faster WP and greater TMV were also associated with lower odds of glaucoma in men only (P = 0.004 and P = 0.017, respectively). Stronger GS-IOP associations were observed in participants with a higher level of genetic risk for glaucoma (Pinteraction < 0.001).

In this cross-sectional and gene-environment interaction study, factors relating to muscle strength, mass, and function were consistently associated with higher IOP, thicker inner retinal OCT measures in both sexes, and lower odds of glaucoma in men.