Type-1 diabetes is associated with autoantibodies and activated lymphocytes which are reactive with p cell antigens . Its course is characterized by a symptomless prediabetic phase whose presence can be inferred from immune markers. Pre-type-1 diabetes is a period of accelerated p cell loss, whose tempo varies from acute in those who present young to subacute or chronic in those who present later in life . The differences in tempo are assumed to be under genetic control, since those who develop type-1 diabetes in childhood tend to carry more intensely responsive HLA genes than those who develop it later in life [18, 19]. p cell autoimmunity appears to start early in life, insofar as immune markers predictive of future diabetes can be present as early as at 9 months of age .
Type-2 diabetes is characterised by a combination of insulin resistance and defective insulin response that results from it . Blood insulin concentrations are raised, at least initially, but are never sufficient to meet the resistance that entrains them. Like type-1, type-2 diabetes also presents after a variable period of prediabetes, whose presence might be revealed by high fasting insulin/glucose ratios and later by glycosuria or hyperglycemia in circumstances which temporarily increase insulin resistance - typically pregnancy, thyrotoxicosis or a course of anti-inflammatory steroids. Between 17 and 63% of women whose glycosuria during pregnancy is attributable to glucose intolerance will subsequently become diabetic, depending on the series quoted . Of these, a proportion (around 20% according to one study ) will develop type-1 diabetes, underscoring the principle to be established here that the prediabetes of type 1 and type 2 differs only in tempo, not in outcome. Both represent a period of accelerated p cell loss.
It has long been recognized that islet cells are both metabolically and immunogenically upregulated when functionally stressed by a rising blood sugar . At whatever age it emerges, insulin resistance could be expected to increase p cell stress, and to intensify an immune response in those who are genetically predisposed. The phenomenon of insulin resistance, which as the response to progressively rising body weight has been largely responsible for reducing the age at presentation of type-2 diabetes over recent time, might be doing just the same for type-1 diabetes by promoting the immunological accelerants of p cell death in a progressively younger age group. If there is little clinically to distinguish the two types of diabetes nowadays, there is little fundamentally either.
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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...