Influence of intraocular and blood pressure on brain volumes: Observational and Mendelian randomization analyses

Xianwen Shang; Yu Huang; Susan Zhu; Zhuoting Zhu; Xueli Zhang; Wei Wang; Xiayin Zhang; Jing Liu; Jiahao Liu; Shulin Tang; Zongyuan Ge; Yijun Hu; Honghua Yu; Xiaohong Yang; Mingguang He

doi:10.1016/j.isci.2024.110817

Influence of intraocular and blood pressure on brain volumes: Observational and Mendelian randomization analyses

iScience. 2024 Aug 29;27(11):110817. doi: 10.1016/j.isci.2024.110817. eCollection 2024 Nov 15.

Authors

Xianwen Shang^{1

2

3

4

5}, Yu Huang^{1

2}, Susan Zhu⁶, Zhuoting Zhu^{1

2

3}, Xueli Zhang¹, Wei Wang⁷, Xiayin Zhang^{1

2}, Jing Liu¹, Jiahao Liu⁸, Shulin Tang¹, Zongyuan Ge⁹, Yijun Hu¹, Honghua Yu¹, Xiaohong Yang¹, Mingguang He^{1

3

4

7

5

10}

Affiliations

¹ Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510080, China.
² Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, China.
³ Centre for Eye Research Australia, Melbourne, VIC 3002, Australia.
⁴ School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China.
⁵ Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Kowloon, Hong Kong, China.
⁶ Austin Hospital, University of Melbourne, Melbourne, VIC 3084, Australia.
⁷ State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China.
⁸ Melbourne School of Population and Global Health, University of Melbourne, Melbourne, VIC 3010, Australia.
⁹ Monash e-Research Center, Faculty of Engineering, Airdoc Research, Nvidia AI Technology Research Center, Monash University, Melbourne, VIC 3800, Australia.
¹⁰ Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Hong Kong, China.

Abstract

Intraocular pressure (IOP) is closely correlated with blood pressure (BP), and while BP has been linked to brain volumes, the effect of IOP on brain volumes remains unclear. This study analyzed participants from the UK Biobank with MRI-measured brain volumes. Observational analyses included 8,634 participants for IOP and 36,069 for BP, followed by Mendelian randomization (MR) analyses of 37,410 participants. Observational analyses revealed that each 10-mmHg increase in diastolic BP was linked to a 0.13 mL larger white matter hyperintensity (WMH) after adjusting for covariates. Associations between IOP and brain volumes were more pronounced in younger individuals or those without hypertension. MR analyses confirmed significant relationships between diastolic BP and WMH, and each 5-mmHg increase in IOP reduced gray matter volumes by 3.24 mL. The study suggests that targeting IOP and BP could help prevent brain volume reduction.

Keywords: Bioinformatics; Cardiovascular medicine; Neuroscience.