The metabolic syndrome (MS) is a cluster of metabolic abnormalities with abdominal obesity (increased waist circumference) at its centre. Although all forms of obesity have a negative impact on human health, metabolic syndrome describes a set of particularly adverse biochemical changes accompanying (abdominal) obesity.
These biochemical changes explain the increase in diabetes and cardiovascular disease (heart attack, stroke, heart failure) seen with MS, less clearly seen in those forms of obesity which minimally interfere with metabolism. Recent guidelines therefore identified the metabolic syndrome as a risk factor for cardiovascular disease deserving increased clinical attention. MS is most often identified by having three or more out of five possible abnormalities (components) which form the metabolic syndrome cluster.
These five abnormalities in the cluster are:
- increased waist circumference (abdominal obesity),
- elevated triglycerides (a fat component in the blood),
- low HDL-cholesterol ("good" cholesterol),
- a slightly increased blood glucose level (impaired fasting glycemia: the blood sugar level is not as high as in diabetes but is elevated above normal), and
- high blood pressure.
At present few data are available with regard to MS prevalence in Europe and its early links with early cardiac and vascular damage. Our research from the Asklepios Study indicates that in (young) middle-aged subjects (35-55 year old) MS is frequently present (9-16% of subjects depending on the definition used) and that its presence coincides with a wide range of adverse cardiovascular changes. More specifically we found a strong association between presence of MS and inflammation (a well documented marker of risk for future heart attacks and stroke), thickening and stiffening of the heart (potentially predisposing to heart failure) and more pronounced atherosclerosis (calcification and narrowing of the arteries). Importantly these effects were graded, every additional MS component present translated into a gradually higher likelihood of finding cardiovascular damage. Whilst subjects with one or two metabolic abnormalities do not have a metabolic syndrome (three or more components are necessary by definition), they do have a higher risk than an individual without any metabolic abnormalities. Metabolic syndrome is not only an all/none diagnosis (present in 9-16% of the population) as every additional component of the MS yielded an increase in cardiovascular abnormalities. The implications of the present findings should therefore also be relevant for much larger segment of the population (more than 50%) having at least one MS component. Furthermore our data suggest that although men in this age group have the MS more frequently, that women seem more prone to its adverse consequences. Efforts should be focused on awareness of abdominal obesity as a risk factor for developing heart disease, and on wide ranging preventive strategies to avert its (potentially epidemic) consequences.