The prevalence of type 2 diabetes is rapidly increasing worldwide, primarily due to the global increase in obesity and sedentary lifestyles. Persons with impaired glucose tolerance (IGT) are at increased risk of developing type 2 diabetes and form an important high-risk group for actions aimed at preventing the disease.
Persons with abnormal glucose metabolism are at increased risk for cardiovascular disorders and often exhibit various cardiovascular risk factors.
The clustering of cardiovascular risk factors has been called the metabolic syndrome (MetS). Currently there are four definitions for metabolic syndrome (MetS): the criteria of the World Health Organization (WHO) consultation group, the criteria of the European Group for the Study of Insulin Resistance (EGIR), the criteria of the National Cholesterol Education Program (NCEP) Expert Panel, and the criteria of the American Association of Clinical Endocrinologists.
Type 2 diabetes and IGT are closely associated with the MetS. Clustering of the risk factors associated with this syndrome predicts the development of manifest diabetes and cardiovascular disease. Prevention of type 2 diabetes should therefore aim to prevent and treat several components of the MetS simultaneously (Jeong-Ah Shin. Metabolic syndrome as a predictor of type 2 diabetes, and its clinical interpretations and Usefulness. Journal of Diabetes Investigation Volume 4 Issue 4 July 2013).
The clustering of glucose intolerance, hypertension, dyslipidemia and obesity, particularly central obesity, has been termed metabolic syndrome.
Metabolic syndrome is known to increase cardiovascular morbidity and mortality, type 2 diabetes, and all-cause mortality. The desired clinical response to metabolic syndrome is improved individual and national public health, and a mitigation
of negative outcomes through comprehensive management.
Metabolic syndrome (MS) is a group of clinical and biological abnormalities that confers a greater risk of type 2 diabetes, cardiovascular (CVD) and liver diseases. (Andre P Kengne1* Metabolic syndrome in type 2 diabetes: comparative prevalence according to two sets of diagnostic criteria in sub-Saharan Africans. Kengne et al. Diabetology & Metabolic Syndrome 2012, 4:22)
The different components of MS were initially described by Reaven in 1988 under the appellation of “syndrome X”. These include abdominal obesity, higher-than-optimal blood pressure, disorders of glucose metabolism and abnormal lipid profile. The underlying feature of all these abnormalities seems to be insulin resistance. Regardless of the presence of any abnormalities of glucose metabolism, individuals with MetS are atincreased risk of type 2 diabetes. The co-occurrence of diabetes mellitus and MetS potentiates the cardiovascular risk associated with each of the two conditions. Characterizing MetS in the presence of diabetes is therefore beneficial for the purpose of cardiovascular prevention. Several sets of criteria have been suggested for the diagnosis of MS. These include the criteria by the World Health Organization (WHO, 1998), the European Group for study on insulin Resistance (EGIR) in 1999, the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III) in 2001 and the International Diabetes Federation (IDF) in 2005. The common ground in these criteria hinge on disorders of glucose metabolism, hypertension, dyslipidaemia and obesity.
The IDF 2005 definitionwas based on waist circumference greater than or equal to80 cm (women), greater than or equal to94 cm (men) and any two or more of any of the following: fasting triglycerides ≥ 1.5 g/L or 3.88mmol/L or on triglycerides lowering drugs; fasting HDL cholesterol <0.4 g/L or 1.03mmol/L (men), <0.5 g/L or 1.29mmol/L (women); systolic blood pressure (SBP) greater than or equal to130 mmHg and/or diastolic blood pressure (DBP) greater than or equal to85 mmHg, or on blood pressure lowering treatment; fasting plasma glucose greater than or equal to1 g/l (5.6mmol/L), or previously diagnosed type 2 diabetes.
The NCEP-ATP III definition was based on three or more of any of the following: waist circumference >88 cm (women) 102 cm (men); fasting triglycerides ≥ 1.5 g/L or 3.88mmol/L; fasting HDL cholesterol <0.4 g/L or 1.03mmol/L (men), <0.5 g/L or 1.29mmol/L(women); SBP ≥ 130 mmHg and/or DBF ≥ 85 mmHg; fasting glucose ≥ 1.1 g/L (6.1mmol/L).
Many studies reported that the presence of metabolic syndrome, regardless of definition, was highly predictive of new-onset type 2 diabetes in many different populations. Some studies showed that the relative risk (RR) for incident diabetes is higher than it is for cardiovascular disease(CVD).
Among the components of metabolic syndrome, impaired fasting glucose (IFG) has been shown as the strongest predictor for type 2 diabetes development. The syndrome is used widely and conveniently in clinical practice and research fields; an important aspect of its clinical significance is the ‘visualization’ of the risk for CVD and type 2 diabetes development. By receiving a diagnosis of metabolic syndrome, patients might become motivated to actively carry out lifestyle modifications, and health care providers can implement the focused risk management and comprehensive implementation approaches available to them to reduce major complications.
Early detection of individuals at high risk for type 2 diabetes is essential not only for the prevention of diabetes itself, but also to decrease associated cardiovascular complications. Metabolic syndrome is ideal as a predictor of incident diabetes
Among the five components of metabolic syndrome, IFG is particularly superior for its ability to predict incident diabetes; the other components can predict cardiovascular disease (CVD) better than or similarly to IFG. Most patients with type 2 diabetes possess multiple risk factors for CVD other than hyperglycemia. Because CVD is the leading cause of death in diabetic patients, careful attention should be exercised with regard to all modifiable risk factors.
