Metabolic syndrome: Why the controversy?

As originally conceived, the metabolic syndrome defined a clustering of cardiovascular disease risk factors with insulin resistance as the common, underlying pathophysiologic determinant. The definition of the syndrome has evolved since then, with several groups proposing somewhat differing definitions. Partly, this has been motivated by efforts to make the syndrome a clinically useful entity. However, recent articles have called the clinical use of the metabolic syndrome into question. In this review, some of these concerns and counterarguments for the continued use of the metabolic syndrome are reviewed.     

Metabolic syndrome: Perception or reality?

Metabolic syndrome is associated with increased risk for type 2 diabetes and cardiovascular disease. It has garnered considerable clinical and research interest as a potential target to reduce cardiovascular risk in addition to the classical risk factors. Whether it exists as a distinct clinical entity has become a subject of controversy and debate. This review appraises the evidence in support of or against recognizing metabolic syndrome as a clinical condition that requires therapeutic intervention. Proper evaluation of cardiovascular disease risk should start with consideration of traditional risk factors using validated tools, such as the short-term 10-year Framingham risk score. Individuals with abdominal obesity should be further assessed for associated cardiometabolic risks. Global cardiovascular disease risk should take into consideration not only short-term but also lifetime risks.     

Metabolic syndrome

Corresponding author:Charles Shaeffer,MD,Desert Cardiology Center,Eisenhower Medical Center,39000 Bob Hope Drive,Rancho Mirage,CA92270-3221,USATel:760-346-0182;E-mail:sewfari @ earthlink.net     

Metabolic syndrome: collapsing under its own weight?

Invited counterview to article by Cameron AJ, Zimmet PZ, Shaw JE, Alberti KGMM. The metabolic syndrome: in need of a global mission statement. Diabet Med 2009; 26 : 306–309     

Metabolic syndrome in older subjects: coincidence or clustering?

The prevalence of the metabolic syndrome (MS) increases with advancing age. However, aging per se is associated with increased prevalence of most of the abnormalities contributing to the MS. Whether MS in older people consistently identifies a true pathophysiological entity or a casual aggregation of aging-associated metabolic abnormalities, remains to be fully elucidated. In the present study, we aimed to evaluate whether in older subjects the aggregation of metabolic components of the MS, as defined by the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III), is consistent with a single latent variable. Age, waist circumference, systolic and diastolic blood pressure, metabolic variables were determined in 152 older (>70 years), non-diabetic, healthy men. Cronbach alpha was used to assess the internal consistency of the components contributing to the MS. Structural equation modeling, using the Normed Fit Index (NFI), the Root Mean Square Error of Approximation (RMSEA), the Comparative Fit Index (CFI), and the Tucker-Lewis Index (TLI) was used to assess the fit to a model with a single latent variable. The Cronbach alpha test showed low internal consistency among the metabolic variables (alpha=0.31). The calculated chi(2) values were 28.31 and 32.52 for model entering hypertension as dichotomous variable and for model entering blood pressure values, respectively, both expressing low fit to a model with a single latent variable. In both models, CFI (0.41 and 0.55), NFI (0.59 and 0.55), RMSEA (0.25 and 0.22) and TLI (-0.31 and -0.12) scores showed a low fit of the metabolic alterations to a single latent variable. These findings suggest caution in making diagnosis of MS at older ages, since metabolic and cardiovascular abnormalities being per se extremely common in elderly people, do not appear to cluster together under a single common factor.     

Metabolic syndrome: an ill wind that blows some good?

In this issue of the journal, Brima et al. report thought‐provoking research providing a potential evolutionary rationale whereby natural selection might have preserved genes that predispose to metabolic syndrome. When CD‐1 mice were fed a high fat diet, this induced metabolic changes characteristic of metabolic syndrome. In addition, the high fat diet provided substantial protection from lethality due to infection with Trypanosoma cruzi. The authors hypothesize that the same genes predispose to both metabolic syndrome and protection against infectious disease. Thus, the selective advantage of not dying from infectious disease implicitly provides selective pressure predisposing to metabolic syndrome. This hypothesis follows a similar line of reasoning that has provided explanations for the survival of the HbS mutation for sickle cell disease and renal disease‐associated genetic variants in apolipoprotein L1. Variants in these two genes provide protection from malaria and Trypanosoma brucei rhodesiense, respectively. Copyright © 2015 John Wiley & Sons, Ltd.     

Metabolic syndrome after liver transplantation: Preventable illness or common consequence?

The metabolic syndrome is common after liver transplant being present in approximately half of recipients. It has been associated with adverse outcomes such as progression of hepatitis C and major vascular events. As the United States population ages and the rate of obesity increases, prevention of the metabolic syndrome in the post-transplant population deserves special consideration. Currently, the metabolic syndrome after transplant appears at least two times more common than observed rates in the general population. Specific guidelines for patients after transplant does not exist, therefore prevention rests upon knowledge of risk factors and the presence of modifiable elements. The current article will focus on risk factors for the development of the metabolic syndrome after transplant, will highlight potentially modifiable factors and propose potential areas for intervention. As in the non-transplant population, behavioral choices might have a major role. Opportunities exist in this regard for health prevention studies incorporating lifestyle changes. Other factors such as the need for immunosuppression, and the changing characteristics of wait listed patients are not modifiable, but are important to know in order to identify persons at higher risk. Although immunosuppression after transplant is unavoidable, the contribution of different agents to the development of components of the metabolic syndrome is also discussed. Ultimately, an increased risk of the metabolic syndrome after transplant is likely unavoidable, however, there are many opportunities to reduce the prevalence.     

Chronic vulval ulceration--another immune reconstitution inflammatory syndrome?

We describe a patient who developed intractable chronic vulval ulceration that we believe was related to immune reconstitution following treatment of HIV infection with highly active antiretroviral treatment (HAART). Immune reconstitution inflammatory syndrome should be considered in the differential diagnosis of unexplained vulval ulceration that arises after starting HAART.