Diabetes is a disease in which your blood glucose, or blood sugar, levels are too high. Glucose comes from the foods you eat. Insulin is a hormone that helps the glucose get into your cells to give them energy. With type 1 diabetes, your body does not make insulin. With type 2 diabetes, the more common type, your body does not make or use insulin well. Without enough insulin, the glucose stays in your blood.

Healthy lifestyle choices can help you prevent type 2 diabetes. Even if you have diabetes in your family, diet and exercise can help you prevent the disease. If you've already received a diagnosis of diabetes, you can use healthy lifestyle choices to help prevent complications. And if you have prediabetes, lifestyle changes can slow or halt the progression from prediabetes to diabetes.
Type 2 diabetes can be prevented with lifestyle changes. People who are overweight and lose as little as 7 percent of their body weight and who increase physical activity (for example, walking 30 minutes per day) can decrease their risk of diabetes mellitus by more than 50%. Metformin and acarbose, drugs that are used to treat diabetes, may reduce the risk of diabetes in people with impaired glucose regulation.
Women seem to be at a greater risk as do certain ethnic groups,[10][107] such as South Asians, Pacific Islanders, Latinos, and Native Americans.[23] This may be due to enhanced sensitivity to a Western lifestyle in certain ethnic groups.[108] Traditionally considered a disease of adults, type 2 diabetes is increasingly diagnosed in children in parallel with rising obesity rates.[10] Type 2 diabetes is now diagnosed as frequently as type 1 diabetes in teenagers in the United States.[13]

Diabetes can be hard enough as it is, so do what you can to make life with it less complicated. For example, you don't have to be a master chef to put together a healthy meal. You can use ingredients that are right in your home. If you find your medication regimen to be too complex or too expensive, request that your physician change it. If you continue to forget to take your medicines, find simple ways to help you take them, like setting a reminder on your cell phone.
Because people with type 2 diabetes produce some insulin, ketoacidosis does not usually develop even when type 2 diabetes is untreated for a long time. Rarely, the blood glucose levels become extremely high (even exceeding 1,000 mg/dL). Such high levels often happen as the result of some superimposed stress, such as an infection or drug use. When the blood glucose levels get very high, people may develop severe dehydration, which may lead to mental confusion, drowsiness, and seizures, a condition called hyperosmolar hyperglycemic state. Currently, many people with type 2 diabetes are diagnosed by routine blood glucose testing before they develop such severely high blood glucose levels.

Type 2 diabetes used to be called adult-onset diabetes or non-insulin dependent diabetes because it was diagnosed mainly in adults who did not require insulin to manage their condition. However, because more children are starting to be diagnosed with T2D, and insulin is used more frequently to help manage type 2 diabetes, referring to the condition as “adult-onset” or “non-insulin dependent” is no longer accurate.
Glycated hemoglobin (A1C) test. This blood test indicates your average blood sugar level for the past two to three months. It measures the percentage of blood sugar attached to hemoglobin, the oxygen-carrying protein in red blood cells. The higher your blood sugar levels, the more hemoglobin you'll have with sugar attached. An A1C level of 6.5 percent or higher on two separate tests indicates you have diabetes. A result between 5.7 and 6.4 percent is considered prediabetes, which indicates a high risk of developing diabetes. Normal levels are below 5.7 percent.
Scientists have done studies of twins to help estimate how important genes are in determining one's risk of developing diabetes. Identical twins have identical genes and thus the same genetic risk for a disease. Research has found that if one identical twin has type 1 diabetes, the chance that the other twin will get the disease is roughly 40 or 50 percent. For type 2 diabetes, that risk goes up to about 80 or 90 percent. This might suggest that genes play a bigger role in type 2 than in type 1, but that isn't necessarily so. Type 2 is far more common in the general population than type 1, which means that regardless of genetics both twins are more likely to develop type 2 diabetes.
Healthy lifestyle choices can help you prevent type 2 diabetes. Even if you have diabetes in your family, diet and exercise can help you prevent the disease. If you've already received a diagnosis of diabetes, you can use healthy lifestyle choices to help prevent complications. And if you have prediabetes, lifestyle changes can slow or halt the progression from prediabetes to diabetes.

Periodontal Disease. Periodontal disease is a commonly observed dental problem for patients with diabetes. It is similar to the periodontal disease encountered among nondiabetic patients. However, as a consequence of the impaired immunity and healing associated with diabetes, it may be more severe and progress more rapidly (see Right). The potential for these changes points to the need for periodic professional evaluation and treatment.
It is clearly established that diabetes mellitus is not a single disease but a genetically heterogeneous group of disorders that share glucose intolerance in common (4–7). The concept of genetic heterogeneity (i.e. that different genetic and/or environmental etiologic factors can result in similar phenotypes) has significantly altered the genetic analysis of this common disorder. Diabetes and glucose intolerance are not diagnostic terms, but, like anemia, simply describe symptoms and/or laboratory abnormalities that can have a number of distinct etiologies.

Jump up ^ Seida, Jennifer C.; Mitri, Joanna; Colmers, Isabelle N.; Majumdar, Sumit R.; Davidson, Mayer B.; Edwards, Alun L.; Hanley, David A.; Pittas, Anastassios G.; Tjosvold, Lisa; Johnson, Jeffrey A. (Oct 2014). "Effect of Vitamin D3 Supplementation on Improving Glucose Homeostasis and Preventing Diabetes: A Systematic Review and Meta-Analysis". The Journal of Clinical Endocrinology & Metabolism. 99 (10): 3551–60. doi:10.1210/jc.2014-2136. PMC 4483466. PMID 25062463.


When the glucose concentration in the blood remains high over time, the kidneys will reach a threshold of reabsorption, and glucose will be excreted in the urine (glycosuria).[62] This increases the osmotic pressure of the urine and inhibits reabsorption of water by the kidney, resulting in increased urine production (polyuria) and increased fluid loss. Lost blood volume will be replaced osmotically from water held in body cells and other body compartments, causing dehydration and increased thirst (polydipsia).[60]
Doctors can monitor treatment using a blood test called hemoglobin A1C. When the blood glucose levels are high, changes occur in hemoglobin, the protein that carries oxygen in the blood. These changes are in direct proportion to the blood glucose levels over an extended period. The higher the hemoglobin A1C level, the higher the person's glucose levels have been. Thus, unlike the blood glucose measurement, which reveals the level at a particular moment, the hemoglobin A1Cmeasurement demonstrates whether the blood glucose levels have been controlled over the previous few months.
The prognosis of diabetes is related to the extent to which the condition is kept under control to prevent the development of the complications described in the preceding sections. Some of the more serious complications of diabetes such as kidney failure and cardiovascular disease, can be life-threatening. Acute complications such as diabetic ketoacidosis can also be life-threatening. As mentioned above, aggressive control of blood sugar levels can prevent or delay the onset of complications, and many people with diabetes lead long and full lives.
Because people with type 2 diabetes produce some insulin, ketoacidosis does not usually develop even when type 2 diabetes is untreated for a long time. Rarely, the blood glucose levels become extremely high (even exceeding 1,000 mg/dL). Such high levels often happen as the result of some superimposed stress, such as an infection or drug use. When the blood glucose levels get very high, people may develop severe dehydration, which may lead to mental confusion, drowsiness, and seizures, a condition called hyperosmolar hyperglycemic state. Currently, many people with type 2 diabetes are diagnosed by routine blood glucose testing before they develop such severely high blood glucose levels.
Patients with type 1 diabetes require life-long treatment with exogenous (artificial) insulin to regulate their blood sugar levels. This insulin may be given through the use of a hypodermic needle (seen right), or other methods such as the use of an insulin pump. Over time, many patients suffer chronic complications: vascular, neurological and organ-specific (such as kidney and eye disease). The frequency and severity of these complications is related to duration that the patient has suffered the disease for, and by how well their blood sugar levels have been controlled. If blood sugar levels, blood pressure and lipids are tightly controlled, many complications of diabetes may be prevented. Some patients may develop the major emergency complication of diabetes, known as ketoacidosis (extremely high blood glucose levels accompanied with extremely low insulin levels), which has a mortality rate of 5-10%.

People with diabetes can benefit from education about the disease and treatment, good nutrition to achieve a normal body weight, and exercise, with the goal of keeping both short-term and long-term blood glucose levels within acceptable bounds. In addition, given the associated higher risks of cardiovascular disease, lifestyle modifications are recommended to control blood pressure.[80][81]
Diabetes Mellitus Diabetes Mellitus Complications Diabetes Mellitus Control in Hospital Diabetes Mellitus Glucose Management Diabetes Resources Diabetes Sick Day Management Diabetic Ketoacidosis Diabetic Ketoacidosis Management in Adults Diabetic Ketoacidosis Management in Children Diabetic Ketoacidosis Related Cerebral Edema Hyperosmolar Hyperglycemic State Metabolic Syndrome Type 1 Diabetes Mellitus Type 2 Diabetes Mellitus Type 2 Diabetes Mellitus in Children
DM affects at least 16 million U.S. residents, ranks seventh as a cause of death in the United States, and costs the national economy over $100 billion yearly. The striking increase in the prevalence of DM in the U.S. during recent years has been linked to a rise in the prevalence of obesity. About 95% of those with DM have Type 2, in which the pancreatic beta cells retain some insulin-producing potential, and the rest have Type 1, in which exogenous insulin is required for long-term survival. In Type 1 DM, which typically causes symptoms before age 25, an autoimmune process is responsible for beta cell destruction. Type 2 DM is characterized by insulin resistance in peripheral tissues as well as a defect in insulin secretion by beta cells. Insulin regulates carbohydrate metabolism by mediating the rapid transport of glucose and amino acids from the circulation into muscle and other tissue cells, by promoting the storage of glucose in liver cells as glycogen, and by inhibiting gluconeogenesis. The normal stimulus for the release of insulin from the pancreas is a rise in the concentration of glucose in circulating blood, which typically occurs within a few minutes after a meal. When such a rise elicits an appropriate insulin response, so that the blood level of glucose falls again as it is taken into cells, glucose tolerance is said to be normal. The central fact in DM is an impairment of glucose tolerance of such a degree as to threaten or impair health. Long recognized as an independent risk factor for cardiovascular disease, DM is often associated with other risk factors, including disorders of lipid metabolism (elevation of very-low-density lipoprotein cholesterol and triglycerides and depression of high-density lipoprotein cholesterol), obesity, hypertension, and impairment of renal function. Sustained elevation of serum glucose and triglycerides aggravates the biochemical defect inherent in DM by impairing insulin secretion, insulin-mediated glucose uptake by cells, and hepatic regulation of glucose output. Long-term consequences of the diabetic state include macrovascular complications (premature or accelerated atherosclerosis with resulting coronary, cerebral, and peripheral vascular insufficiency) and microvascular complications (retinopathy, nephropathy, and neuropathy). It is estimated that half those with DM already have some complications when the diagnosis is made. The American Diabetes Association (ADA) recommends screening for DM for people with risk factors such as obesity, age 45 years or older, family history of DM, or history of gestational diabetes. If screening yields normal results, it should be repeated every 3 years. The diagnosis of DM depends on measurement of plasma glucose concentration. The diagnosis is confirmed when any two measurements of plasma glucose performed on different days yield levels at or above established thresholds: in the fasting state, 126 mg/dL (7 mmol/L); 2 hours postprandially (after a 75-g oral glucose load) or at random, 200 mg/dL (11.1 mmol/L). A fasting plasma glucose of 100-125 mg/dL (5.5-6.9 mmol/L) or a 2-hour postprandial glucose of 140-199 mg/dL (7.8-11 mmol/L) is defined as impaired glucose tolerance. People with impaired glucose tolerance are at higher risk of developing DM within 10 years. For such people, lifestyle modification such as weight reduction and exercise may prevent or postpone the onset of frank DM. Current recommendations for the management of DM emphasize education and individualization of therapy. Controlled studies have shown that rigorous maintenance of plasma glucose levels as near to normal as possible at all times substantially reduces the incidence and severity of long-term complications, particularly microvascular complications. Such control involves limitation of dietary carbohydrate and saturated fat; monitoring of blood glucose, including self-testing by the patient and periodic determination of glycosylated hemoglobin; and administration of insulin (particularly in Type 1 DM), drugs that stimulate endogenous insulin production (in Type 2 DM), or both. The ADA recommends inclusion of healthful carbohydrate-containing foods such as whole grains, fruits, vegetables, and low-fat milk in a diabetic diet. Restriction of dietary fat to less than 10% of total calories is recommended for people with diabetes, as for the general population. Further restriction may be appropriate for those with heart disease or elevated cholesterol or triglyceride levels. The ADA advises that high-protein, low-carbohydrate diets have no particular merit in long-term weight control or in maintenance of a normal plasma glucose level in DM. Pharmaceutical agents developed during the 1990s improve control of DM by enhancing responsiveness of cells to insulin, counteracting insulin resistance, and reducing postprandial carbohydrate absorption. Tailor-made insulin analogues produced by recombinant DNA technology (for example, lispro, aspart, and glargine insulins) have broadened the range of pharmacologic properties and treatment options available. Their use improves both short-term and long-term control of plasma glucose and is associated with fewer episodes of hypoglycemia. SEE ALSO insulin resistance
When you have diabetes, excess sugar (glucose) builds up in your blood. Your kidneys are forced to work overtime to filter and absorb the excess sugar. If your kidneys can't keep up, the excess sugar is excreted into your urine, dragging along fluids from your tissues. This triggers more frequent urination, which may leave you dehydrated. As you drink more fluids to quench your thirst, you'll urinate even more.

The genes identified so far in people with type 2 include many that affect the insulin-producing beta cells of the pancreas, says Craig Hanis, PhD, a professor at the Human Genetics Center at the University of Texas Health Science Center in Houston. And yet he emphasizes that why people get type 2 isn't at all clear yet: "What it tells us is that diabetes is a complicated disease."
Several other signs and symptoms can mark the onset of diabetes although they are not specific to the disease. In addition to the known ones above, they include blurred vision, headache, fatigue, slow healing of cuts, and itchy skin. Prolonged high blood glucose can cause glucose absorption in the lens of the eye, which leads to changes in its shape, resulting in vision changes. Long-term vision loss can also be caused by diabetic retinopathy. A number of skin rashes that can occur in diabetes are collectively known as diabetic dermadromes.[23]
The Diabetes Control and Complications Trial (DCCT) was a clinical study conducted by the United States National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) that was published in the New England Journal of Medicine in 1993. Test subjects all had diabetes mellitus type 1 and were randomized to a tight glycemic arm and a control arm with the standard of care at the time; people were followed for an average of seven years, and people in the treatment had dramatically lower rates of diabetic complications. It was as a landmark study at the time, and significantly changed the management of all forms of diabetes.[86][130][131]
“It’s not like you wake up one day and all of a sudden you’re thirsty, hungry, and [going to the bathroom] all the time,” says Melissa Joy Dobbins, RD, a certified diabetes educator in Illinois and a spokesperson for the American Association of Diabetes Educators. “It picks up gradually.” Indeed, “most people are unaware that they have diabetes in its early or even middle phases,” says Aaron Cypess, MD, assistant professor of medicine at Harvard Medical School and staff physician at Joslin Diabetes Center. Just because you’re not keyed in doesn’t mean you’re immune from problems associated with diabetes, he adds. The longer you go without controlling diabetes, the greater your risk for heart disease, kidney disease, amputation, blindness, and other serious complications. “We recommend that people with risk factors for diabetes, such as a family history or being overweight, get evaluated on a regular basis,” Dr. Cypess says. If you’ve been feeling off, talk to your doctor about getting a simple blood test that can diagnose the disease. And pay attention to these subtle signs and symptoms of diabetes.
"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.[39] 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).[39] These phenomena are believed to occur no more frequently than in 1% to 2% of persons with type 1 diabetes.[40]
Diabetes mellitus is a chronic disease caused by inherited and/or acquired deficiency in production of insulin by the pancreas, or by the ineffectiveness of the insulin produced. Such a deficiency results in increased concentrations of glucose in the blood, which in turn damage many of the body's systems, in particular the blood vessels and nerves.
The protocol for therapy is determined by the type of diabetes; patients with either type 1 or type 2 must pay attention to their diet and exercise regimens. Insulin therapy may be prescribed for patients with type 2 diabetes as well as any who are dependent on insulin. In most cases, the type 2 diabetes patient can be treated effectively by reducing caloric intake, maintaining target weight, and promoting physical exercise.

Can type 2 diabetes be prevented? It is possible to reduce the risk of developing type 2 diabetes, although the underlying risk of type 2 diabetes depends strongly on genetic factors. But there was less type 2 diabetes around some years ago when people had a more active life and didn’t eat a modern Western diet. So it is fair to say that risk of getting type 2 diabetes is based on a genetic predisposition that is aggravated by lifestyle. Type 2 diabetes is associated with obesity, as well as a variety of environmental factors. To lower the risk of developing type 2 diabetes (as well as other diseases), it is highly recommended to exercise often, eat healthily, and maintain a healthy weight. 

In patients with type 2 diabetes, stress, infection, and medications (such as corticosteroids) can also lead to severely elevated blood sugar levels. Accompanied by dehydration, severe blood sugar elevation in patients with type 2 diabetes can lead to an increase in blood osmolality (hyperosmolar state). This condition can worsen and lead to coma (hyperosmolar coma). A hyperosmolar coma usually occurs in elderly patients with type 2 diabetes. Like diabetic ketoacidosis, a hyperosmolar coma is a medical emergency. Immediate treatment with intravenous fluid and insulin is important in reversing the hyperosmolar state. Unlike patients with type 1 diabetes, patients with type 2 diabetes do not generally develop ketoacidosis solely on the basis of their diabetes. Since in general, type 2 diabetes occurs in an older population, concomitant medical conditions are more likely to be present, and these patients may actually be sicker overall. The complication and death rates from hyperosmolar coma is thus higher than in diabetic ketoacidosis.
Patients with type 1 DM, unless they have had a pancreatic transplant, require insulin to live; intensive therapy with insulin to limit hyperglycemia (“tight control”) is more effective than conventional therapy in preventing the progression of serious microvascular complications such as kidney and retinal diseases. Intensive therapy consists of three or more doses of insulin injected or administered by infusion pump daily, with frequent self-monitoring of blood glucose levels as well as frequent changes in therapy as a result of contacts with health care professionals. Some negative aspects of intensive therapy include a three times more frequent occurrence of severe hypoglycemia, weight gain, and an adverse effect on serum lipid levels, i.e., a rise in total cholesterol, LDL cholesterol, and triglycerides and a fall in HDL cholesterol. Participation in an intensive therapy program requires a motivated patient, but it can dramatically reduce eye, nerve, and renal complications compared to conventional therapy. See: insulin pump for illus.
If you are symptomatic (e.g., increased thirst or urination, unexplained weight loss), your doctor may only use a single test to diagnose diabetes/prediabetes. If you don't have any symptoms, one high blood glucose test doesn't necessarily mean you have diabetes/prediabetes. Your doctor will repeat one of the blood tests again on another day (generally 1 week later) to confirm the diagnosis.
Long-term complications arise from the damaging effects of prolonged hyperglycemia and other metabolic consequences of insulin deficiency on various tissues. Although long-term complications are rare in childhood, maintaining good control of diabetes is important to prevent complications from developing in later life. [39] The likelihood of developing complications appears to depend on the interaction of factors such as metabolic control, genetic susceptibility, lifestyle (eg, smoking, diet, exercise), pubertal status, and gender. [40, 41] Long-term complications include the following:
Abnormal cholesterol and triglyceride levels. If you have low levels of high-density lipoprotein (HDL), or "good," cholesterol, your risk of type 2 diabetes is higher. Triglycerides are another type of fat carried in the blood. People with high levels of triglycerides have an increased risk of type 2 diabetes. Your doctor can let you know what your cholesterol and triglyceride levels are.
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