Association between serum homocysteine and arterial stiffness: role of antihypertensive drugs.

To the Editor

I read the article of Zhang, et al.[1] with great interest. They investigated the association of homocysteine with arterial stiffness in Chinese community-based elderly persons. The carotid-femoral pulse wave velocity (PWV) was significantly higher in the high homocyteine group than in the normal one, however, there was no differences in carotid-radial PWV between the high homocyteine group and the normal one. Homocysteine levels were strongly associated with the carotid-femoral PWV even after adjustment for classical risk factors of cardiovascular disease. I congratulate the authors for this important study. However, I want to make minor criticism for this study from the methodological aspect.

It is known that arterial stiffness is a complex process and it is closely associated with confounding factors. Recently, Cecelja, et al.[2] published a systematic review which showed that the contribution of cardiovascular risk factors other than age and blood pressure to aortic stiffness measured by carotid-femoral PWV is small or insignificant and age and blood pressure were consistently independently associated with aortic stiffness. As a result, this systematic review showed that age and blood pressure were consistently independently associated with aortic stiffness in majority of studies. It has also been shown that some antihypertensive drugs like angiotensin-converting enzyme inhibitors, calcium channel blockers and spiranolactone reduce arterial stiffness.[3],[4] When we look at the study, there is 45% hypertensive subjects in the normal homocysteine group and 51% hypertensive subjects in the high one. However, there is no data of antihypertensive drugs used. Also statins reduce arterial stiffness and there is also no data about statin use.[3] It would have been useful if the authors had provided this information.

Arterial stiffness describes the reduced capability of an artery to expand and contract in response to pressure changes and it is an independent predictor of cardiovascular morbidity and all-cause mortality.[3] It has been suggested that aortic stiffness occurs as a result of atherosclerosis along the aorta. However, it is closely associated with confounding factors like antihypertensive drugs and statins. Some antihypertensive drugs and statins can greatly influence arterial stiffness and these factors should be considered in arterial stiffness evaluation.

We thank Dr.Varol for his interest in our article on the association between serum homocysteine and arterial stiffness in the elderly. Our study is a community-based study. Patients with overt CVD have exactly been excluded. Although many hypertensive subjects have been found after the measurement, the number of subjects who took regular medication, such as aspirin, statins, β-blockers, angiotensin-converting enzyme inhibitors (ACE-Is) and angiotensin-receptor blockers (ARBs) was small. Data were adjusted for model 2 in Table 2 plus using of the above-mentioned medications. The relation between aortic stiffness and homocysteine did not change after further controlling for the use of these medications.