<International Circulation>: Metabolic syndrome， a major risk factor for cardiovascular disease， is a common and growing problem in the world. But some scientists question this concept especially its clinic instructive value.  It is not contested that cardiovascular risk factors tend to cluster together， but what is contested is the assertion that the metabolic syndrome is anything more than the sum of its constituent parts. What is your opinion on this aspect?

   Prof. Smith: There is a growing body of evidence to suggest that it is in fact more than the sum of its parts when looked at individually， but it is complicated because there are some components of the metabolic syndrome that are not measured. For instance， the pro-thrombotic state and the hyperinflammatory response are both part of it. I think the question is still open， if we had ways to assess pro-thrombotic state and the hyperinflammatory response as well as whatever element of hypertension or dyslipidemia might be present， then if we were to sum them up， we would find a relative equivalence. There is currently work underway on new guidelines at NIH which will involve an approach to understand multiple risk factors which may yield an answer. It is going to be highly evidence-based work. The evidence is growing to confirm the hypothesis that the metabolic syndrome does have a risk that is somewhat additive than that of the factors that are being measured. My concern is that we don’t really measure all of the factors as I stated previously. The discussions here at WCC are centered around another problem with the metabolic syndrome and that is with the differences in definition – whether or not one needed to have an increase in waist circumference or visceral adiposity as part of it. There was an international meeting held in London that resulted in a publication tackling this concept and involving the NIH， the AHA and a large number of groups concerned with the metabolic syndrome each of whom had slightly different diagnoses. The paper has been published now resulting in agreement by all with regard to the components and also agreeing that waist circumference is not an essential component， although it is present in most people， but importantly， that waist circumference varies based on ethnic background. Different waist circumferences are recommended largely derived from IDF and AHA data， with a very strong request that data be gathered in every part of the world about risk and its relationship to waist circumference. In south-east Asia， we know the risk factors for metabolic syndrome occur at a much lower waist circumference than they do in European or American Caucasians. So I think we have our definitions and we have our agreement， and we also have a challenge to do more work before we are going to truly understand some of the important questions here.