The causative factors for diabetes are diverse and range from infections to single-gene defects with complex environmental and biological interactions probably predominant.
Scientific progress and better understanding of diabetes had led to a classification expanding from describing a single disease state to distinguishing at least four different types of diabetes mellitus. This number of overall sub-types may not be expanded in future because the classification allows newly described specific types of diabetes with a distinct aetiology to be moved out of the type 2 class (a largely aetiologically insufficiently understood class of DM) to type 3 (other specific types).
The classification of diabetes into different types is driven by differing needs, including aetiological research and clinical practice. The old descriptive age-of-onset classes gave way to a treatment-related classification, which has in turn been superseeded by a system based on aetiology. Type 4 diabetes (Gestational Diabetes Mellitus) is still the exception, as the basis for classification is the common context rather than aetiology.
The diagnostic criteria for diabetes are based on the common characteristic of hyperglycaemia. Achievements in accuracy and methodological standardisation of internationally accepted testing procedures have resulted in the widespread application of two diagnostic tests; fasting blood glucose determination and measurement of blood glucose two hours after an oral glucose tolerance test. In the near future, a third marker of hyperglycaemia, HbA1c, is likely to be added to this list.
The acceptance of a diagnostic standard across the various aetiologic subtypes of DM has resulted in considerable progress in describing the epidemiology of diabetes. With improved characterisations of diabetic phenotypes across many populations and sub-groups (such as the elderly), it is apparent that the threshold distinguishing normal and abnormal blood glucose levels may not be universal. If this observation is correct, it is a major challenge to diagnostic uniformity, and several important diabetes studies have already elected to apply their own criteria in parallel with standard international
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Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...