Metabolic syndrome

The metabolic syndrome, also known as the dysmetabolic syndrome, metabolic syndrome X, or insulin resistance syndrome, is a major public health concern worlwide. The growing obesity epidemic is its most noticeable effect, but the metabolic syndrome can be present in the absence of frank obesity. Almost one fourth of Americans have metabolic syndrome, and the proportion keeps raising. The metabolic syndrome is a serious disturbance of body metabolism and physiology, consisting of resistance of certain cell types of the body to the ability of the hormone insulin to promote cellular entry of the energy-rich molecule, glucose, and two or more of the following abnormalities: high blood pressure (or use of drugs to control hypertension); high levels of serum triglycerides; low levels of high-density lipoprotein (HDL) cholesterol; overweight; detectable levels of the protein, albumin, in the urine (microalbuminuria). The abnormalities of triglyceride levels typically associate with other blood fat disturbances (dyslipidemia) that foster atherosclerosis (buildup of plaques in artery walls the predispose to reduced blood flow to vital organs (e.g., the heart) and to formation of blood clots that can break off and clog vital vessels to the brain, causing stroke. The biochemical factors that promote clot formation are also stimulated in the metabolic syndrome, and the syndrome appears to be one of a chronic state of inflammation, the typical body response to tisue injury.

Criteria

There exists different clinical definitions of the metabolic syndrome. There is disagreement about the relative importance of insulin resistance in the cluster of risk factors, and two definitions do not require this risk factor.

It is defined by the World Health Organisation using the following criteria:

• Insulin resistance, identified by one of the following:
  • Type 2 diabetes
  • Impaired fasting glucose
  • Impaired glucose tolerance
  • or, for those with normal fasting glucose levels (<110mg/dL), glucose uptake below the lowest quartile for background population under investigation under hyperinsulinemic, euglycemic conditions
• in conjunction with any two of the following:
  • Antihypertensive medication and/or high blood pressure (≥140mmHg systolic or ≥90mmHg diastolic)
  • Plasma triglycerides ≥150mg/dL (≥1.7mmol/L)
  • HDL cholesterol <35mg/dL (0.9mmol/L) in men or <39mg/dL (1.0mmol/L) in women
  • BMI (Body Mass Index) >30kg/m² and/or waist:hip ratio >0.9 in men, >0.85 in women
  • Urinary albumin excretion rate ≥20μmg/g or albumin: creatinine ratio ≥30 mg/g.

Psychological components

An interesting but yet underdevelopped aspect of research on the metabolic syndrome relates to the syndrome's psychological components. Cynical hostility appears to predict the metabolic syndrome, which in turn predicts cardiovascular disease. Worthy of note, in a study, only high hostility and low HDL cholesterol predicted coronary heart disease. At present, there is no agreement on the nature of the relationship between hostility and the metabolic syndrome.

Consequences of the metabolic syndrome

Diabetic complications and cardiovascular diseases

The metabolic syndrome is thus a cluster of risk factors for diabetes complications and cardiovascular diseases. The syndrome includes proinflammatory and prothrombotic features.

Other consequences

The metabolic syndrome could also promote the development of cancer, polycystic ovary syndrome (PCOS), and nonalcoholic fatty liver disease".

Cancer

A number of components of the metabolic syndrome (MS) are likely to contribute, especially in combination, to cause cancer. While the MS-colon cancer is the most convincing link, other epidemiologic studies investigating the link of MS with other cancers are awaited.