Criteria for diagnosing the metabolic syndrome

Department of Internal Medicine
Niigata Prefectural Yoshida Hospital
Yoshida Daibochou 32-14
Tsubame
Niigata 959-0242
Japan
E-mail: ijie{at}venus.sannet.ne.jp

Dear Sir:

I read a recent review in the Journal by Grundy (1), which claimed some value in diagnosing the metabolic syndrome in clinical practice. This claim is in contrast with the view expressed by Reaven (2) in the same issue of the Journal. Reaven stated that 1) providers should avoid labeling patients with the term metabolic syndrome, 2) adults with any major cardiovascular disease (CVD) risk factor should be evaluated for the presence of other CVD risk factors, and 3) all CVD risk factors should be individually and aggressively treated in accord with the joint statement by the American Diabetes Association and the European Association for the Study of Diabetes (3). Grundy emphasized that obesity is a risk factor for CVD. However, neither abdominal obesity nor the metabolic syndrome, defined on the basis of the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATPIII) criteria, was shown to be a significant independent risk factor for CVD in multiple regression analyses (4, 5).

Obesity has recently become regarded as an endocrine disease rather than as an anthropometric disorder, and mutual relations between insulin resistance, endothelial dysfunction, and inflammation are recognized to be central mechanisms of the metabolic syndrome (6). Furthermore, a high C-reactive protein (CRP) concentration has been established as a strong independent risk factor for CVD (7) and is significantly positively related to insulin resistance (8) and leptin concentrations (9) and significantly negatively related to adiponectin concentrations (10) in persons with a normal body mass index. Grundy included the proinflammatory state in his clustering of metabolic risk factors (metabolic syndrome) but did not include obesity in this clustering in his Figure 1 (1). Therefore, I propose that CRP concentration be included as one of the NCEP-ATP III's criteria for diagnosing the metabolic syndrome and that waist circumference be excluded from the criteria. We previously reported in Japan that a CRP concentration of 0.65 mg/L is the optimal cutoff value to be used as a criterion for the metabolic syndrome (11). Until such time that this criterion, or any other new criterion, for defining the metabolic syndrome is proven to be a significant independent risk factor for CVD, we should not label persons as having the metabolic syndrome.

ACKNOWLEDGMENTS

The author had no conflict of interest to disclose.

REFERENCES

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