The Associations Between Blood Levels of Homocysteine, Folate, Vitamin B12, and Retinal Vascular Caliber

Gopinath, Bamini; Wang, Jie Jin; Flood, Victoria M.; Burlutsky, George; Wong, Tien Y.; Mitchell, Paul

doi:10.1016/j.ajo.2009.07.018

« Previous Next »American Journal of Ophthalmology
Volume 148, Issue 6 , Pages 902-909, December 2009

The Associations Between Blood Levels of Homocysteine, Folate, Vitamin B₁₂, and Retinal Vascular Caliber

Bamini Gopinath
- Centre for Vision Research, Department of Ophthalmology, Westmead Millennium Institute, University of Sydney, Sydney, New South Wales, Australia
- Menzies Centre for Health Policy, University of Sydney, Sydney, New South Wales, Australia
Jie Jin Wang
- Centre for Vision Research, Department of Ophthalmology, Westmead Millennium Institute, University of Sydney, Sydney, New South Wales, Australia
- Centre for Eye Research Australia, Department of Ophthalmology, University of Melbourne, Melbourne, Australia
Victoria M. Flood
- Centre for Vision Research, Department of Ophthalmology, Westmead Millennium Institute, University of Sydney, Sydney, New South Wales, Australia
- Public Health Nutrition Group, Institute of Obesity, Nutrition and Exercise, University of Sydney, New South Wales, Australia
George Burlutsky
- Centre for Vision Research, Department of Ophthalmology, Westmead Millennium Institute, University of Sydney, Sydney, New South Wales, Australia
Tien Y. Wong
- Centre for Eye Research Australia, Department of Ophthalmology, University of Melbourne, Melbourne, Australia
- Singapore Eye Research Institute, National University of Singapore, Singapore
Paul Mitchell
- Centre for Vision Research, Department of Ophthalmology, Westmead Millennium Institute, University of Sydney, Sydney, New South Wales, Australia
- Inquiries to Paul Mitchell, Centre for Vision Research, University of Sydney, Westmead Hospital, Hawkesbury Road, Westmead, NSW, 2145, Australia

Accepted 16 July 2009. published online 01 October 2009.

Purpose

To assess the association of total serum levels of homocysteine (tHcy), folate, and vitamin B₁₂ with retinal vascular caliber in older adults.

Design

Cross-sectional, population-based study.

Methods

One thousand seven hundred and seventy-two of 2334 Blue Mountains Eye Study participants examined had fundus photographs taken and retinal arteriolar and venular caliber measured using computer-assisted techniques and summarized. Serum folate and vitamin B₁₂ levels and tHcy were determined from venous blood samples. Linear regression models adjusting for age, gender, mean arterial blood pressure, smoking, and diabetes were used to assess whether serum levels of tHcy, folate, and vitamin B₁₂ were associated with retinal arteriolar and venular caliber.

Results

Arteriolar and venular caliber was not associated with tHcy in the total population. Further analysis demonstrated a significant serum homocysteine–gender interaction (P = .04). A significant inverse association between tHcy and arteriolar caliber was found in men only (P = .03), with a threshold detected at a level of 17 μmol/l. Above this threshold, increasing tHcy was linearly associated with narrower arteriolar caliber (0.86 μm reduction per 1.0 μmol/l increase in tHcy) in men, but no significant association was found below this threshold. No significant associations were observed between serum folate or vitamin B₁₂ levels and either retinal vessel caliber.

Conclusions

Retinal vascular caliber is associated with tHcy in men but not women. This finding may reflect the stronger association between blood pressure and tHcy in men than in women.