Metabolic syndrome and non-cardiac vascular diseases: an update from human studies.

The metabolic syndrome (MetS) is characterized by a cluster of risk factors including central obesity, hypertension, dyslipidemia and insulin resistance, The MetS is associated with an increased risk for cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM). Several international organizations have defined MetS using different diagnostic criteria that produced discrepancies in the results of previous studies, thus leading to the latest Joint Interim Societies (JIS) MetS definition. Other risk factors than the diagnostic criteria that have been associated with MetS include lipid abnormalities, uric acid, liver function, prothrombotic factors, cytokines, adipokines, vitamin D, arterial stiffness, polycystic ovary syndrome and obstructive sleep apnea. Apart from CVD and T2DM, MetS has been related to non-cardiac vascular diseases and in particular to stroke, carotid artery disease, peripheral artery disease, chronic kidney disease, atherosclerotic renal artery stenosis and abdominal aortic aneurysms. In this narrative review, the associations of these diseases with MetS and its components will be discussed. These associations may further increase CVD risk in MetS patients, highlighting the importance of treating such high-risk individuals early and "to target". In this context, multifactorial treatment including a statin has been proven beneficial, and thus should be considered, in MetS patients.