Metabolic syndrome may make arteries thicker and stiffer

“Metabolic syndrome increased both the thickness of the carotid artery, which is a measure of its structure, and the stiffness, which is a measure of the carotid artery function in both younger and older subjects. But the very interesting thing is that younger subjects with metabolic syndrome were at the same level as older people without metabolic syndrome; so it’s as if metabolic syndrome makes your blood vessels older,” said Angelo Scuteri, MD, PhD, from the National Institute on Aging, National Institutes of Health in Baltimore, Maryland and U.O. Geriatria, INRCA in Rome, Italy.

Metabolic syndrome, which is also sometimes called insulin resistance syndrome, is a cluster of several cardiovascular risk factors in an individual, including impaired glucose tolerance, high blood pressure, low HDL cholesterol and abdominal obesity.

This study involved a sample of participants from the Baltimore Longitudinal Study of Aging, a long-running study of how people age, which is supported by the National Institute on Aging. The researchers analyzed data from 471 men and women who were free of preexisting coronary artery disease. The data included measurements of blood pressure, body shape and mass, smoking, cholesterol and blood sugar, as well as ultrasound scans of the right common carotid artery.

The subjects with metabolic syndrome had carotid arteries that were 16 percent thicker and 32 percent stiffer than the arteries of those without those risk factors. The risk factors appear to work synergistically; that is, subjects with at least three risk factors had thicker and stiffer arteries than could be explained by simply summing up the effect of each individual risk factor.

Dr. Scuteri said their results indicate that physicians should consider treating patients with metabolic syndrome as though they were older than the calendar says they are.

“Our main message is that metabolic syndrome somehow accelerates the age-related changes in blood vasculature. So it’s like meeting someone who is 40, but looks 60. If you have metabolic syndrome, when you are 40 your arteries look like they are 55 or 60. So we should look at the arteries and offer people with metabolic syndrome more intensive therapeutic or preventive strategies,” Dr. Scuteri said.

In an editorial in the journal, Michael Domanski, MD, FACC and Michael Proschan, PhD, from the National Heart, Lung, and Blood Institute in Bethesda, Md., wrote that this study adds further data to those from earlier research suggesting synergy among the risk factors comprising metabolic syndrome. However, they noted important issues remain to be settled in order for researchers and clinicians to make progress against metabolic syndrome.

“A better understanding of how to best define this syndrome is needed, including what components should be part of the definition and how they should be measured. Also, delineation of the etiology of the syndrome, including heterogeneity of etiology, will be useful in refining prevention and treatment strategies. The daunting dimensions of the apparent risk factor epidemic represented by the metabolic syndrome, combined with the suggestion that effective prevention and treatment paradigms are likely possible, strongly motivates research on this entity,” Drs. Domanski and Proschan wrote.

The American College of Cardiology, a 29,000-member nonprofit professional medical society and teaching institution, is dedicated to fostering optimal cardiovascular care and disease prevention through professional education, promotion of research, leadership in the development of standards and guidelines, and the formulation of health care policy.