The present analysis has shown that amongst the various components of the MetS, waist circumference is the component that most significantly influences the micro-inflammatory response. Invariably, Waist and BMI are used inter-changeably in the definition of the metabolic syndrome and there is in fact a strong association between them. Due to this association, adjusting for waist and BMI together causes problematic co-linearity. However, it must be noted that waist circumference still remained the most significant predictor of the inflammatory response even after additional adjustment for BMI. There is a known association between the MetS and the presence of micro-inflammation [32–34] but to the best of our knowledge, the relative contribution of the different MetS components to the low grade, sub-clinical inflammatory response has not been previously evaluated. Thus, our findings contribute original information to the literature being the largest analysis to date evaluating the association between inflammation and each individual component of the metabolic syndrome in adults. A previous analysis from our group regarding the hypertriglyceridemic waist phenotype, evaluated this phenotype and its relation to inflammation . This phenotype however, although related to the metabolic syndrome, has different definitions from the metabolic syndrome. The previous work evaluated this difference and did not analyze the relative weight of each component of the metabolic syndrome. The importance of the current analysis stems from the detrimental effect that the presence of micro-inflammation has on the pathogenesis of atherothrombosis, insulin resistance, [7, 9] and cardiovascular morbidity and mortality [10–12]. This study has analyzed commonly used inflammatory markers with known atherosclerotic significance. High sensitivity C-reactive protein has been shown to have deleterious effects on vascular biology, white blood cells can contribute to endothelial injury and fibrinogen is related to hyperviscosity, which in turn can also contribute to vascular events . Thus, the presence of these markers could represent a link between the individual components of the MetS and the development of the atherosclerotic disease.
The prevalence of the MetS in our cohort was relatively low. In fact only 9.6% of women and 11.7% of men had three MetS components or more. One possible explanation for this is the fact that this study was performed in a group of relatively healthy individuals. However, this population could represent those individuals that are still not affected by the results of long standing atherosclerotic disease and might therefore benefit from preventive interventions. In addition, it should be stressed that we did not limit ourselves to individuals with an established diagnosis of MetS. We wanted to discover the relationship between the presence of micro-inflammation and changes in each individual component of the MetS, even in individuals without defined MetS. Theoretically, our findings can be used to support the recent report by Arnlov et al  that have demonstrated that overweight and obese individuals without MetS are as well at an increased risk for cardiovascular mortality and morbidity. It is crucial to understand that preventative measures should be implemented early, even when only one or two components are present, since even a mild increase in inflammation and the presence of one or two MetS components can be associated with a significant increase in future risk of MetS development. Our study is therefore relevant not only for those individuals who meet all the criteria of the MetS but even for individuals who are in a pre-MetS state. Furthermore, the clinical importance of our findings is also strengthened by the work of Ridker et al. . The Jupiter trial showed that statin therapy in apparently healthy persons without hyperlipidemia but with elevated C-reactive protein levels significantly reduced the incidence of major cardiovascular events. Thus, elevated waist circumference as the primary contributor of the inflammatory state in the MetS, could by itself in the future be a possible indication for statin therapy .
In conclusion, a clarification of the relationship between each MetS component and the intensity of the micro-inflammatory response may be of clinical relevance. Such a clarification might help to highlight the importance of targeted interventions such as weight reduction, a measure previously proved to be clearly beneficial [40, 41].