Type 2 diabetes (T2D), formerly known as adult-onset diabetes, is a form of diabetes that is characterized by high blood sugar, insulin resistance, and relative lack of insulin.[6] Common symptoms include increased thirst, frequent urination, and unexplained weight loss.[3] Symptoms may also include increased hunger, feeling tired, and sores that do not heal.[3] Often symptoms come on slowly.[6] Long-term complications from high blood sugar include heart disease, strokes, diabetic retinopathy which can result in blindness, kidney failure, and poor blood flow in the limbs which may lead to amputations.[1] The sudden onset of hyperosmolar hyperglycemic state may occur; however, ketoacidosis is uncommon.[4][5]
A systematic review suggested that patients with type 2 diabetes who have a baseline HbA1c of greater than 8% may achieve better glycemic control when given individual education rather than usual care. Outside that subgroup, however, the report found no significant difference between usual care and individual education. In addition, comparison of individual education with group education showed equal impact on HbA1c at 12-18 months. [98]

Genetics, lifestyle and environment can be causes of diabetes. Eating an unhealthy diet, being overweight or obese and not exercising enough may play a role in developing diabetes, particularly Type 2 diabetes. Type 1 diabetes is caused by an autoimmune response. The body’s immune system attacks and destroys the insulin producing beta cells in the pancreas.
Yamasaki et al found that abnormal results on single-photon CT myocardial perfusion imaging in asymptomatic patients with type 2 diabetes indicated a higher risk for cardiovascular events (13%), including cardiac death. Smoking and low glomerular filtration rate were significant contributing factors. [80] However, an earlier study questioned the merit of routine screening with adenosine-stress radionuclide myocardial perfusion imaging (MPI) in otherwise asymptomatic type 2 diabetic patients (the Detection of Ischemia in Asymptomatic Diabetics [DIAD] study). [81]
^ Qaseem A, Wilt TJ, Kansagara D, Horwitch C, Barry MJ, Forciea MA (April 2018). "Hemoglobin A1c Targets for Glycemic Control With Pharmacologic Therapy for Nonpregnant Adults With Type 2 Diabetes Mellitus: A Guidance Statement Update From the American College of Physicians". Annals of Internal Medicine. 168 (8): 569–576. doi:10.7326/M17-0939. PMID 29507945.
Most cases of diabetes involve many genes, with each being a small contributor to an increased probability of becoming a type 2 diabetic.[10] If one identical twin has diabetes, the chance of the other developing diabetes within his lifetime is greater than 90%, while the rate for nonidentical siblings is 25–50%.[13] As of 2011, more than 36 genes had been found that contribute to the risk of type 2 diabetes.[39] All of these genes together still only account for 10% of the total heritable component of the disease.[39] The TCF7L2 allele, for example, increases the risk of developing diabetes by 1.5 times and is the greatest risk of the common genetic variants.[13] Most of the genes linked to diabetes are involved in beta cell functions.[13]
^ Imperatore G, Boyle JP, Thompson TJ, Case D, Dabelea D, Hamman RF, Lawrence JM, Liese AD, Liu LL, Mayer-Davis EJ, Rodriguez BL, Standiford D (December 2012). "Projections of type 1 and type 2 diabetes burden in the U.S. population aged <20 years through 2050: dynamic modeling of incidence, mortality, and population growth". Diabetes Care. 35 (12): 2515–20. doi:10.2337/dc12-0669. PMC 3507562. PMID 23173134. Archived from the original on 2016-08-14.
The World Health Organization recommends testing those groups at high risk[56] and in 2014 the USPSTF is considering a similar recommendation.[60] High-risk groups in the United States include: those over 45 years old; those with a first degree relative with diabetes; some ethnic groups, including Hispanics, African-Americans, and Native-Americans; a history of gestational diabetes; polycystic ovary syndrome; excess weight; and conditions associated with metabolic syndrome.[23] The American Diabetes Association recommends screening those who have a BMI over 25 (in people of Asian descent screening is recommended for a BMI over 23).[61]
Accumulating evidence suggests that depression is a significant risk factor for developing type 2 diabetes. Pan et al found that the relative risk was 1.17 in women with depressed mood and 1.25 in women using antidepressants. [56] Antidepressant use may be a marker of more severe, chronic, or recurrent depression, or antidepressant use itself may increase diabetes risk, possibly by altering glucose homeostasis or promoting weight gain.
We don’t know what causes gestational diabetes, but we know that you are not alone. It happens to millions of women. We do know that the placenta supports the baby as it grows. Sometimes, these hormones also block the action of the mother’s insulin to her body and it causes a problem called insulin resistance. This insulin resistance makes it hard for the mother’s body to use insulin. And this means that she may need up to three times as much insulin to compensate. 
Regardless, check with your doctor and get tested. If you discover that you do have prediabetes, remember that it doesn’t mean you’ll develop type 2, particularly if you follow a treatment plan and a diet and exercise routine. Even small changes can have a huge impact on managing this disease or preventing it all together—so get to a doctor today and get tested.
In animals, diabetes is most commonly encountered in dogs and cats. Middle-aged animals are most commonly affected. Female dogs are twice as likely to be affected as males, while according to some sources, male cats are also more prone than females. In both species, all breeds may be affected, but some small dog breeds are particularly likely to develop diabetes, such as Miniature Poodles.[126]
The prognosis in people with type 2 diabetes varies. It depends on how well an individual modifies his or her risk of complications. Heart attack, stroke and kidney disease can result in premature death. Disability due to blindness, amputation, heart disease, stroke and nerve damage may occur. Some people with type 2 diabetes become dependent on dialysis treatments because of kidney failure.
Unlike people with type 1 diabetes, people with type 2 diabetes produce insulin; however, the insulin their pancreas secretes is either not enough or the body is unable to recognize the insulin and use it properly. This is called insulin resistance. When there isn't enough insulin or the insulin is not used as it should be, sugar (glucose) can't get into the body's cells to be used for fuel. When sugar builds up in the blood instead of going into cells, the body's cells are not able to function properly. Other problems associated with the build up of sugar in the blood include:
Albers JW, Herman WH, Pop-Busui R, Feldman EL, Martin CL, Cleary PA, et al. Effect of prior intensive insulin treatment during the Diabetes Control and Complications Trial (DCCT) on peripheral neuropathy in type 1 diabetes during the Epidemiology of Diabetes Interventions and Complications (EDIC) Study. Diabetes Care. 2010 May. 33(5):1090-6. [Medline]. [Full Text].
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.[114] 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.[114] 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.[114] This was followed by the development of the long acting NPH insulin in the 1940s.[114]
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.[114] 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.[114] 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.[114] This was followed by the development of the long acting NPH insulin in the 1940s.[114]
In countries using a general practitioner system, such as the United Kingdom, care may take place mainly outside hospitals, with hospital-based specialist care used only in case of complications, difficult blood sugar control, or research projects. In other circumstances, general practitioners and specialists share care in a team approach. Home telehealth support can be an effective management technique.[103]
This content is provided as a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health. The NIDDK translates and disseminates research findings through its clearinghouses and education programs to increase knowledge and understanding about health and disease among patients, health professionals, and the public. Content produced by the NIDDK is carefully reviewed by NIDDK scientists and other experts.
Agency for Healthcare Research and Quality. Comparative Effectiveness, Safety, and Indications of Insulin Analogues in Premixed Formulations for Adults With Type 2 Diabetes. AHRQ: Agency for Healthcare Research and Quality. Available at http://www.effectivehealthcare.ahrq.gov/index.cfm/search-for-guides-reviews-and-reports/?productid=108&pageaction=displayproduct.. Accessed: March 7, 2012.
Type 2 diabetes used to be known as adult-onset diabetes, but today more children are being diagnosed with the disorder, probably due to the rise in childhood obesity. There's no cure for type 2 diabetes, but losing weight, eating well and exercising can help manage the disease. If diet and exercise aren't enough to manage your blood sugar well, you may also need diabetes medications or insulin therapy.
Differences between the patient populations in these studies and the UKPDS may account for some of the differences in outcome. The patients in these 3 studies had established diabetes and had a prior cardiovascular disease event or were at high risk for a cardiovascular disease event, whereas patients in the UKPDS study were younger, with new-onset diabetes and low rates of cardiovascular disease.
In people with insulin resistance, the pancreas "sees" the blood glucose level rising. The pancreas responds by making extra insulin to maintain a normal blood sugar. Over time, the body's insulin resistance gets worse. In response the pancreas makes more and more insulin. Finally, the pancreas gets "exhausted". It cannot keep up with the demand for more and more insulin. It poops out. As a result, blood glucose levels start to rise.
Two types of diabetes were identified as separate conditions for the first time by the Indian physicians Sushruta and Charaka in 400–500 CE with one type being associated with youth and another type with being overweight.[111] 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.[111] Effective treatment was not developed until the early part of the 20th century, when Canadians Frederick Banting and Charles Herbert Best isolated and purified insulin in 1921 and 1922.[111] This was followed by the development of the long-acting insulin NPH in the 1940s.[111]
A randomized, controlled trial found that for patients with poorly controlled diabetes, individual attention and education is superior to group education. [96] Similarly, a diabetes education and self-management group program in the UK for newly diagnosed patients failed to yield significant benefits. [97] Nonphysician health professionals are usually much more proficient at diabetes education and have much more time for this very important activity.
A systematic review suggested that patients with type 2 diabetes who have a baseline HbA1c of greater than 8% may achieve better glycemic control when given individual education rather than usual care. Outside that subgroup, however, the report found no significant difference between usual care and individual education. In addition, comparison of individual education with group education showed equal impact on HbA1c at 12-18 months. [98]
Schizophrenia has been linked to the risk for type 2 diabetes. Dysfunctional signaling involving protein kinase B (Akt) is a possible mechanism for schizophrenia; moreover, acquired Akt defects are associated with impaired regulation of blood glucose and diabetes, which is overrepresented in first-episode, medication-naive patients with schizophrenia. [58] In addition, second-generation antipsychotics are associated with greater risk for type-2 diabetes.
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.[62] 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.[62]
Eating a balanced diet is vital for people who have diabetes, so work with your doctor or dietitian to set up a menu plan. If you have type 1 diabetes, the timing of your insulin dosage is determined by activity and diet. When you eat and how much you eat are just as important as what you eat. Usually, doctors recommend three small meals and three to four snacks every day to maintain the proper balance between sugar and insulin in the blood.
Vascular diseases that prevent blood flow to the small blood vessels are common if you have diabetes. Nerve damage may also occur with longstanding diabetes. Since restricted blood flow and nerve damage can affect the feet in particular, you should make regular visits to a podiatrist. With diabetes, you may also have a reduced ability to heal blisters and cuts, even minor ones. A podiatrist can monitor your feet for any serious infections that could lead to gangrene and amputation. These visits do not take the place of daily foot checks you do yourself.
Type 2 diabetes is a chronic disease. It is characterized by high levels of sugar in the blood. Type 2 diabetes is also called type 2 diabetes mellitus and adult-onset diabetes. That's because it used to start almost always in middle- and late-adulthood. However, more and more children and teens are developing this condition. Type 2 diabetes is much more common than type 1 diabetes, and is really a different disease. But it shares with type 1 diabetes high blood sugar levels, and the complications of high blood sugar.
Genome-wide association studies of single-nucleotide polymorphisms (SNPs) have identified a number of genetic variants that are associated with beta-cell function and insulin resistance. Some of these SNPs appear to increase the risk for type 2 diabetes. Over 40 independent loci demonstrating an association with an increased risk for type 2 diabetes have been shown. [16] A subset of the most potent are shared below [17] :
Susceptibility to type 2 diabetes may also be affected by genetic variants involving incretin hormones, which are released from endocrine cells in the gut and stimulate insulin secretion in response to digestion of food. For example, reduced beta-cell function has been associated with a variant in the gene that codes for the receptor of gastric inhibitory polypeptide (GIPR). [23]
It is a good idea to wear a MedicAlert bracelet or tag that says you have diabetes. This will make others aware of your condition in case you have a severe hypoglycemic attack and are not able to make yourself understood, or if you are in an accident and need emergency medical care. Identifying yourself as having diabetes is important because hypoglycemic attacks can be mistaken for drunkenness, and victims often aren't able to care for themselves. Without prompt treatment, hypoglycemia can result in a coma or seizures. And, because your body is under increased stress when you are ill or injured, your blood sugar levels will need to be checked by the medical personnel who give you emergency care.
"Brittle" diabetes, also known as unstable diabetes or labile diabetes, is a term that was traditionally used to describe the dramatic and recurrent swings in glucose levels, often occurring for no apparent reason in insulin-dependent diabetes. This term, however, has no biologic basis and should not be used.[40] Still, type 1 diabetes can be accompanied by irregular and unpredictable high blood sugar levels, frequently with ketosis, and sometimes with serious low blood sugar levels. Other complications include an impaired counterregulatory response to low blood sugar, infection, gastroparesis (which leads to erratic absorption of dietary carbohydrates), and endocrinopathies (e.g., Addison's disease).[40] These phenomena are believed to occur no more frequently than in 1% to 2% of persons with type 1 diabetes.[41]

This happens because constantly high levels of sugar in the blood stream can damage the blood vessels of the penis, or the blood vessels supplying the nerves to the penis. When the blood vessels and nerves are damaged, the blood flow to the penis is significantly reduced, resulting in erectile dysfunction. Other causes of erectile dysfunction include smoking, heart disease, high blood pressure and high cholesterol levels.
A British study indicated that the HbA1c level achieved 3 months after the initial diagnosis of type 2 diabetes mellitus predicts subsequent mortality. In other words, according to the report, aggressive lowering of glucose after diagnosis bodes well for long-term survival. (Intensified diabetes control must be introduced gradually in newly diagnosed patients.) [75]
You must regularly visit an eye doctor, such an optometrist or ophthalmologist, to check for these potentially serious conditions. According to guidelines from the American Diabetes Association, people with type 1 diabetes should have an annual dilated comprehensive eye exam beginning five years after diagnosis. People with type 2 diabetes should have this comprehensive dilated eye exam yearly beginning at diagnosis.
Type 2 diabetes occurs when the body does not produce enough insulin, or when the cells are unable to use insulin properly, which is called insulin resistance. Type 2 diabetes is commonly called “adult-onset diabetes” since it is diagnosed later in life, generally after the age of 45. It accounts for 90-95 percent of people with diabetes. In recent years, Type 2 diabetes has been diagnosed in younger people, including children, more frequently than in the past.
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