Abstract
Purpose :
To identify serum metabolites associated with intraocular pressure (IOP) in a Chinese population
Methods :
We enrolled Chinese subjects from the Singapore Chinese Eye Study, a population-based study of ocular disease in adults Singaporeans. Each subject underwent a standardized clinical examination, and bio-samples were collected from each of them. IOP was measured using Goldmann tonometry. The serum samples were analyzed using proton Nuclear Magnetic Resonance (NMR) spectroscopy to quantify 228 metabolites, including amino acids, glycolysis measures, ketone bodies and fatty acids, lipid concentrations and compositions of 14 lipoprotein subclasses. Eyes with IOP lowering treatment were excluded from the analysis. Multivariable linear regression analysis was used to evaluate the association between serum metabolites and IOP, adjusting for potential confounders, such as age, gender, BMI, blood pressure, smoking status, central corneal thickness and lipid-lowering medication. The regression coefficient (β) represented the change in IOP (in mmHg) for every one standard deviation (SD) increase in the metabolite levels. The significance level was set at P =2.2x10-4 (0.05/228 for multiple testing).
Results :
We included a total of 5,734 eyes from 2,867 participants for analysis. The mean (SD) age of the study subjects was 58.8 (9.5) years, and the mean IOP was 14.3 (3.1) mm Hg. Multivariable regression analysis showed that 12 serum metabolites were significantly associated with IOP. Higher levels of albumin (β =0.35, P =1.5x10-7; SD of albumin =0.004 mmol/L) and 10 lipoprotein subclasses (β per SD ranged from 0.22 to 0.29, all P <1.9x10-4) were associated with higher IOP. The 10 lipoproteins subclasses included cholesterol esters in medium HDL, total cholesterol in medium HDL, free cholesterol in medium HDL, total lipids in medium HDL, phospholipids in medium HDL, concentration of medium HDL particles, free cholesterol in small HDL, total lipids in small HDL, phospholipids in small HDL, and concentration of small HDL particles. By contrast, higher levels of glutamine were associated with lower IOP (β =-0.23, P =1.2x10-4; SD of glutamine =0.062 mmol/L).
Conclusions :
We identified novel serum metabolites, in particular HDL subclasses and albumin, associated with higher IOP. Our findings may provide further insights into the relationship of systemic metabolic profiles with IOP and glaucoma.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.