This Article Full Text (PDF) All Versions of this Article: 48/2/e10    most recent 01.HYP.0000231652.97173.4cv1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Liew, G. Articles by Wang, J. J. Search for Related Content PubMed PubMed Citation Articles by Liew, G. Articles by Wang, J. J. Related Collections Clinical Studies Other etiology Other Vascular biology

(Hypertension. 2006;48:e10.)
© 2006 American Heart Association, Inc.

Letters to the Editor

Are Narrower or Wider Retinal Venules Associated With Incident Hypertension?

Gerald Liew

Department of Ophthalmology, Westmead Millennium Institute, Centre for Vision Research (Westmead Hospital), University of Sydney, Sydney, Australia

Tien Yin Wong

Centre for Eye Research Australia, University of Melbourne, Victoria, Australia, and Singapore Eye Research Institute, National University of Singapore, Singapore

Paul Mitchell; Jie Jin Wang

Department of Ophthalmology, Westmead Millennium Institute, Centre for Vision Research (Westmead Hospital), University of Sydney, Sydney, Australia

To the Editor:

Ikram et al¹ reported recently that both retinal arteriolar and venular narrowing predict incident hypertension. The relationship between retinal arteriolar narrowing and incident hypertension has been clearly demonstrated in previous studies,^2–4 but the reported association between retinal venular narrowing and incident hypertension is new. In fact, studies suggest that prehypertensive damage to the microcirculation leads to chronic retinal hypoperfusion, ischemia, and widening of venular caliber.⁵ We, therefore, sought to replicate these findings in the Blue Mountains Eye Study, hypothesizing that wider venular caliber is associated with incident hypertension.

We measured retinal vessel calibers in the same way as Ikram et al¹ but used a higher blood pressure (BP) threshold to define hypertension (systolic BP 160 mm Hg, diastolic BP 100 mm Hg, or current use of antihypertensive medications).⁴ We constructed 2 models containing: (1) covariates plus either arteriolar calibers, venular calibers, or the arteriole-to-venule ratio; and (2) covariates plus both arteriolar and venular calibers simultaneously.

Incident hypertension was detected in 390 of 1319 persons without hypertension at baseline (Table). In model 1, narrower arteriolar caliber and smaller arteriole-to-venule ratio were associated with 5-year incident hypertension but not wider venular caliber. In model 2, incident hypertension was independently associated with not only narrower arteriolar caliber (odds ratio, 1.42; 95% CI, 1.20 to 1.67, per SD decrease in arteriolar caliber) but also with wider retinal venular caliber (odds ratio, 1.28; 95% CI, 1.09 to 1.50, per SD increase in venular caliber).

View this table: [in this window] [in a new window]   Retinal Vessel Caliber and Odds Ratios (95% CIs) of 5-Year Incident Hypertension

The stronger association found for narrowing of retinal arterioles and widening of retinal venules in model 2 suggests a confounding effect of arteriolar and venular calibers that was not accounted for in model 1. Arteriolar and venular calibers are correlated (r=0.59), and persons with narrower arterioles are more likely to have narrower venules. This confounding effect may explain the counterintuitive association between retinal venular narrowing and hypertension observed by Ikram et al.¹ We now show that after controlling for arteriolar caliber, wider retinal venular caliber was associated with incident hypertension, a result consistent with the pathophysiology of retinal vessel caliber changes. Our findings further highlight the need to understand the role of retinal vascular caliber in relation to risk of hypertension and other cardiovascular conditions.

	Acknowledgments

 
Sources of Funding

Supported by the Australian National Health and Medical Research Council, Canberra Australia (grants 153948 and 302068).

Disclosures

None.

	References

Top References

 

1. Ikram MK, Witteman JC, Vingerling JR, Breteler MM, Hofman A, de Jong PT. Retinal vessel diameters and risk of hypertension. The Rotterdam Study. Hypertension. 2006; 47: 189–194.[Abstract/Free Full Text]
2. Wong TY, Klein R, Sharrett AR, Duncan BB, Couper DJ, Klein BE, Hubbard LD, Nieto FJ. Retinal arteriolar diameter and risk for hypertension. Ann Intern Med. 2004; 140: 248–255.[Abstract/Free Full Text]
3. Wong TY, Shankar A, Klein R, Klein BE, Hubbard LD. Prospective cohort study of retinal vessel diameters and risk of hypertension. BMJ. 2004; 329: 379.[CrossRef]
4. Smith W, Wang JJ, Wong TY, Rochtchina E, Klein R, Leeder SR, Mitchell P. Retinal arteriolar narrowing is associated with 5-year incident severe hypertension: the Blue Mountains Eye Study. Hypertension. 2004; 44: 442–447.[Abstract/Free Full Text]
5. Saldivar E, Cabrales P, Tsai AG, Intaglietta M. Microcirculatory changes during chronic adaptation to hypoxia. Am J Physiol Heart Circ Physiol. 2003; 285: H2064–H2071.[Abstract/Free Full Text]

This article has been cited by other articles:

				T. T. Nguyen, J. J. Wang, F.M. A. Islam, P. Mitchell, R. J. Tapp, P. Z. Zimmet, R. Simpson, J. Shaw, and T. Y. Wong Retinal Arteriolar Narrowing Predicts Incidence of Diabetes: The Australian Diabetes, Obesity and Lifestyle (AusDiab) Study Diabetes, March 1, 2008; 57(3): 536 - 539. [Abstract] [Full Text] [PDF]

				T. Y. Wong, N. Cheung, F. M. A. Islam, R. Klein, M. H. Criqui, M. F. Cotch, J. J. Carr, B. E. K. Klein, and A. R. Sharrett Relation of Retinopathy to Coronary Artery Calcification: The Multi-Ethnic Study of Atherosclerosis Am. J. Epidemiol., January 1, 2008; 167(1): 51 - 58. [Abstract] [Full Text] [PDF]

				H. Kan, J. Stevens, G. Heiss, R. Klein, K. M Rose, and S. J London Dietary fiber intake and retinal vascular caliber in the Atherosclerosis Risk in Communities Study Am. J. Clinical Nutrition, December 1, 2007; 86(6): 1626 - 1632. [Abstract] [Full Text] [PDF]

				A. Kifley, G. Liew, J. J. Wang, S. Kaushik, W. Smith, T. Y. Wong, and P. Mitchell Long-term Effects of Smoking on Retinal Microvascular Caliber Am. J. Epidemiol., December 1, 2007; 166(11): 1288 - 1297. [Abstract] [Full Text] [PDF]

				T. T. Nguyen, J. J. Wang, and T. Y. Wong Retinal Vascular Changes in Pre-Diabetes and Prehypertension: New findings and their research and clinical implications Diabetes Care, October 1, 2007; 30(10): 2708 - 2715. [Full Text] [PDF]

				N. Cheung, A. R. Sharrett, R. Klein, M. H. Criqui, F.M. A. Islam, K. J. Macura, M. F. Cotch, B. E.K. Klein, and T. Y. Wong Aortic Distensibility and Retinal Arteriolar Narrowing: The Multi-Ethnic Study of Atherosclerosis Hypertension, October 1, 2007; 50(4): 617 - 622. [Abstract] [Full Text] [PDF]

				N. Cheung, D. A. Bluemke, R. Klein, A. R. Sharrett, F.M. A. Islam, M. F. Cotch, B. E.K. Klein, M. H. Criqui, and T. Y. Wong Retinal Arteriolar Narrowing and Left Ventricular Remodeling: The Multi-Ethnic Study of Atherosclerosis J. Am. Coll. Cardiol., July 3, 2007; 50(1): 48 - 55. [Abstract] [Full Text] [PDF]

				S. Kaushik, A. Kifley, P. Mitchell, and J. J. Wang Age, Blood Pressure, and Retinal Vessel Diameter: Separate Effects and Interaction of Blood Pressure and Age Invest. Ophthalmol. Vis. Sci., February 1, 2007; 48(2): 557 - 561. [Abstract] [Full Text] [PDF]

				M. K. Ikram, J. C.M. Witteman, J. R. Vingerling, M. M.B. Breteler, A. Hofman, and P. T.V.M. de Jong Response to Are Narrower or Wider Retinal Venules Associated With Incident Hypertension? Hypertension, August 1, 2006; 48(2): e11 - e11. [Full Text] [PDF]

This Article Full Text (PDF) All Versions of this Article: 48/2/e10    most recent 01.HYP.0000231652.97173.4cv1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Liew, G. Articles by Wang, J. J. Search for Related Content PubMed PubMed Citation Articles by Liew, G. Articles by Wang, J. J. Related Collections Clinical Studies Other etiology Other Vascular biology