Diabetes mellitus is not a single disorder but a heterogeneous group of disorders. All forms are characterized by hyperglycemia and disturbances of carbohydrate, fat, and protein metabolism which are associated with absolute or relative deficiencies of insulin action and/or insulin secretion. The World Health Organization (WHO) developed a now widely accepted classification of the disorder, largely based on clinical characteristics (see Table 1, WHO, 1985).
Oral glucose tolerance test (OGTT): With this test you will be required to fast for at least 8 hours and then are given a drink with 75 g of carbohydrate. Your blood glucose is checked at fasting and then 2 hours after drinking the solution. If your blood glucose is 11.1 mmol/L or higher, your doctor may diagnose diabetes. If your blood glucose 2 hours after drinking the solution is between 7.8 to 11.1 mmol/L, your doctor may diagnose prediabetes. This is the preferred method to test for gestational diabetes.
Diabetes mellitus is a diagnostic term for a group of disorders characterized by abnormal glucose homeostasis resulting in elevated blood sugar. There is variability in its manifestations, wherein some individuals have only asymptomatic glucose intolerance, while others present acutely with diabetic ketoacidosis, and still others develop chronic complications such as nephropathy, neuropathy, retinopathy, or accelerated atherosclerosis. It is among the most common of chronic disorders, affecting up to 5–10% of the adult population of the Western world. Its prevalence varies over the globe, with certain populations, including some American Indian tribes and the inhabitants of Micronesia and Polynesia, having extremely high rates of diabetes (1,2). The prevalence of diabetes is increasing dramatically and it has been estimated that the worldwide prevalence will increase by more than 50% between the years 2000 and 2030 (3).
Jump up ^ Piwernetz K, Home PD, Snorgaard O, Antsiferov M, Staehr-Johansen K, Krans M (May 1993). "Monitoring the targets of the St Vincent Declaration and the implementation of quality management in diabetes care: the DIABCARE initiative. The DIABCARE Monitoring Group of the St Vincent Declaration Steering Committee". Diabetic Medicine. 10 (4): 371–7. doi:10.1111/j.1464-5491.1993.tb00083.x. PMID 8508624.
Diabetes also can cause heart disease and stroke, as well as other long-term complications, including eye problems, kidney disease, nerve damage, and gum disease. While these problems don't usually show up in kids or teens who've had type 2 diabetes for only a few years, they can affect them in adulthood, particularly if their diabetes isn't well controlled.

While many experts believe that most type 1 genes have been identified, the situation with type 2 diabetes is much different. A recent study found that the known genetic links to type 2 probably account for only about 6 percent of the genetic predisposition for that form of diabetes. This could mean either that some of the genes discovered have a bigger effect than is currently believed or that "we are still missing 94 percent of the genes," says Atul Butte, MD, PhD, an assistant professor of pediatrics at Stanford University.
^ Jump up to: a b c d Inzucchi, SE; Bergenstal, RM; Buse, JB; Diamant, M; Ferrannini, E; Nauck, M; Peters, AL; Tsapas, A; Wender, R; Matthews, DR (March 2015). "Management of hyperglycaemia in type 2 diabetes, 2015: a patient-centred approach. Update to a Position Statement of the American Diabetes Association and the European Association for the Study of Diabetes". Diabetologia. 58 (3): 429–42. doi:10.1007/s00125-014-3460-0. PMID 25583541.
In addition to learning about diabetes itself, older people may have to learn how to fit management of diabetes in with their management of other disorders. Learning about how to avoid complications, such as dehydration, skin breakdown, and circulation problems, and to manage factors that can contribute to complications of diabetes, such as high blood pressure and high cholesterol levels, is especially important. Such problems become more common as people age, whether they have diabetes or not.
Type 1 and type 2 diabetes were identified as separate conditions for the first time by the Indian physicians Sushruta and Charaka in 400–500 AD with type 1 associated with youth and type 2 with being overweight.[110] The term "mellitus" or "from honey" was added by the Briton John Rolle in the late 1700s to separate the condition from diabetes insipidus which is also associated with frequent urination.[110] Effective treatment was not developed until the early part of the 20th century when the Canadians Frederick Banting and Charles Best discovered insulin in 1921 and 1922.[110] This was followed by the development of the long acting NPH insulin in the 1940s.[110]

It is especially important that persons with diabetes who are taking insulin not skip meals; they must also be sure to eat the prescribed amounts at the prescribed times during the day. Since the insulin-dependent diabetic needs to match food consumption to the available insulin, it is advantageous to increase the number of daily feedings by adding snacks between meals and at bedtime.
Patients with Type I diabetes need daily injections of insulin to help their bodies use glucose. The amount and type of insulin required depends on the height, weight, age, food intake, and activity level of the individual diabetic patient. Some patients with Type II diabetes may need to use insulin injections if their diabetes cannot be controlled with diet, exercise, and oral medication. Injections are given subcutaneously, that is, just under the skin, using a small needle and syringe. Injection sites can be anywhere on the body where there is looser skin, including the upper arm, abdomen, or upper thigh.

Classic symptoms of DM are polyuria, polydipsia, and weight loss. In addition, patients with hyperglycemia often have blurred vision, increased food consumption (polyphagia), and generalized weakness. When a patient with type 1 DM loses metabolic control (such as during infections or periods of noncompliance with therapy), symptoms of diabetic ketoacidosis occur. These may include nausea, vomiting, dizziness on arising, intoxication, delirium, coma, or death. Chronic complications of hyperglycemia include retinopathy and blindness, peripheral and autonomic neuropathies, glomerulosclerosis of the kidneys (with proteinuria, nephrotic syndrome, or end-stage renal failure), coronary and peripheral vascular disease, and reduced resistance to infections. Patients with DM often also sustain infected ulcerations of the feet, which may result in osteomyelitis and the need for amputation.

Blood travels throughout your body, and when too much glucose (sugar) is present, it disrupts the normal environment that the organ systems of your body function within. In turn, your body starts to exhibit signs that things are not working properly inside—those are the symptoms of diabetes people sometimes experience. If this problem—caused by a variety of factors—is left untreated, it can lead to a number of damaging complications such as heart attacks, strokes, blindness, kidney failure, and blood vessel disease that may require an amputation, nerve damage, and impotence in men.

Type 2 diabetes primarily occurs as a result of obesity and lack of exercise.[1] Some people are more genetically at risk than others.[6] Type 2 diabetes makes up about 90% of cases of diabetes, with the other 10% due primarily to diabetes mellitus type 1 and gestational diabetes.[1] In diabetes mellitus type 1 there is a lower total level of insulin to control blood glucose, due to an autoimmune induced loss of insulin-producing beta cells in the pancreas.[12][13] Diagnosis of diabetes is by blood tests such as fasting plasma glucose, oral glucose tolerance test, or glycated hemoglobin (A1C).[3]
There is an overall lack of public awareness of the signs and symptoms of type 1 diabetes. Making yourself aware of the signs and symptoms of type 1 diabetes is a great way to be proactive about your health and the health of your family members. If you notice any of these signs or symptoms, it’s possible that you have (or your child has) type 1 diabetes. A doctor can make that diagnosis by checking blood glucose levels.

Diabetes mellitus is not a single disorder but a heterogeneous group of disorders. All forms are characterized by hyperglycemia and disturbances of carbohydrate, fat, and protein metabolism which are associated with absolute or relative deficiencies of insulin action and/or insulin secretion. The World Health Organization (WHO) developed a now widely accepted classification of the disorder, largely based on clinical characteristics (see Table 1, WHO, 1985).

Unlike many health conditions, diabetes is managed mostly by you, with support from your health care team (including your primary care doctor, foot doctor, dentist, eye doctor, registered dietitian nutritionist, diabetes educator, and pharmacist), family, and other important people in your life. Managing diabetes can be challenging, but everything you do to improve your health is worth it!
There’s no cure for type 1 diabetes. People with type 1 diabetes don’t produce insulin, so it must be regularly injected into your body. Some people take injections into the soft tissue, such as the stomach, arm, or buttocks, several times per day. Other people use insulin pumps. Insulin pumps supply a steady amount of insulin into the body through a small tube.
 Type 1 diabetes mellitus is a chronic metabolic syndrome defined by an inability to produce insulin, a hormone which lowers blood sugar. This leads to inappropriate hyperglycaemia (increased blood sugar levels) and deranged metabolism of carbohydrates, fats and proteins. Insulin is normally produced in the pancreas, a glandular organ involved in the production of digestive enzymes and hormones such as insulin and glucagon. These functions are carried out in the exocrine and endocrine (Islets of Langerhans) pancreas respectively.
The body obtains glucose from three main sources: the intestinal absorption of food; the breakdown of glycogen (glycogenolysis), the storage form of glucose found in the liver; and gluconeogenesis, the generation of glucose from non-carbohydrate substrates in the body.[60] Insulin plays a critical role in balancing glucose levels in the body. Insulin can inhibit the breakdown of glycogen or the process of gluconeogenesis, it can stimulate the transport of glucose into fat and muscle cells, and it can stimulate the storage of glucose in the form of glycogen.[60]

But preventing the disease from progressing if you already have it requires first being able to spot the signs and symptoms of diabetes when they appear. While some type 2 diabetes symptoms may not ever show up, you can watch out for the following common signs of the disease and alert your doctor, especially if you have any of the common risk factors for diabetes. Also keep in mind that while most signs of type 2 diabetes are the same in men and women, there are some distinctions.