Association Between Body Composition and Risk of Primary Open-Angle Glaucoma.

Area of Science:

• Ophthalmology
• Metabolic Health
• Epidemiology

Background:

• Body mass index (BMI) associations with primary open-angle glaucoma (POAG) are inconsistent.
• BMI does not distinguish between fat and lean mass or capture body composition distribution.
• The impact of specific body composition metrics on POAG risk remains largely unexamined.

Purpose of the Study:

• To investigate the association between body composition (fat and muscle mass distribution) and POAG risk.
• To examine the relationship between body composition and intraocular pressure (IOP).

Main Methods:

• A combined cross-sectional and cohort study utilizing UK Biobank data (88,123 participants for IOP, 291,983 for POAG incidence).
• Bioimpedance analysis estimated fat and muscle mass in the arm, trunk, and leg, normalized for height.
• Covariate-adjusted Cox models estimated hazard ratios (HRs) for POAG incidence, and linear regression assessed associations with IOP.

Main Results:

• Increased leg fat mass, indicated by leg fat index (LFI) and leg fat-to-muscle ratio (FMR), was significantly associated with reduced POAG risk (HRs < 1, P < .01).
• No significant association was found between muscle mass and POAG incidence.
• Greater fat mass was linked to higher IOP (positive β coefficients for AFI, LFI, TFI).
• Greater leg muscle index (LMI) and trunk muscle index (TMI) were associated with lower IOP (negative β coefficients).

Conclusions:

• POAG risk is influenced by body composition patterns, specifically fat distribution.
• Maintaining a healthy body composition, characterized by adequate leg fat, may play a role in mitigating POAG risk.
• Body composition provides a more nuanced understanding of POAG risk than BMI alone.