Central artery stiffness in individuals with metabolic syndrome: Lifestyle modification and its long-term effect on carotid artery stiffness.

摘要

Cardiovascular disease (CVD) is reaching an epidemic level. Not only are populations aging but also CVD risk factors often coexist, a condition known as the metabolic syndrome (MS) that increases CVD risk. An increase in arterial stiffness has emerged as one of the possible mechanisms that link MS and CVD. Therefore, a strategy to reduce arterial stiffness may also reduce CVD risks. The overall objective of this thesis was to examine the effectiveness of lifestyle modification prescribed by family physicians on central artery stiffness in individuals with MS. The first study (Chapter 2) revealed that the presence of MS increased carotid artery stiffness in middle-aged and older individuals (mean of 53.5 yrs) but the increase was not synergistic. The finding led to the second study (Chapter 3) determining whether a 24-week lifestyle modification would reduce carotid artery stiffness in individuals with MS. The results demonstrated that the 24-week lifestyle modification program prescribed by family physicians effectively reduced carotid artery stiffness as well as some components of MS (blood pressure, waist circumference, and blood glucose). Due to the relationship between arterial stiffness and endothelial function, the subsequent study (Chapter 4) investigated the effect of the same lifestyle modification used in the previous study on endothelial function. Despite improvements in blood pressure, waist circumference and glucose, the intervention had no impact on endothelial function. The final study (Chapter 5) investigated how carotid artery stiffness would change with a 1-year lifestyle modification, a long period of washout (mean of 26.9 months) from the active lifestyle intervention, and a subsequent 24-week angiotensin receptor blocker telmisartan treatment in individuals at risk for CVD. Interestingly, the reduced carotid artery stiffness achieved with the 1-year lifestyle intervention was maintained following the cessation of active lifestyle intervention. Overall, these results suggest that lifestyle modification prescribed by family physicians can effectively reduce carotid artery stiffness in individuals at risk for CVD such as MS. They also suggest that the involvement of family physicians may have a sustainable effect on carotid artery stiffness even after the cessation of active lifestyle intervention by regular interaction with their patients.;Key words. aerobic exercise, aging, angiotensin II type-1 receptor, arterial stiffness, flow-mediated dilation, Mediterranean-style diet, metabolic syndrome.