People with type 1 diabetes are unable to produce any insulin at all. People with type 2 diabetes still produce insulin, however, the cells in the muscles, liver and fat tissue are inefficient at absorbing the insulin and cannot regulate glucose well. As a result, the body tries to compensate by having the pancreas pump out more insulin. But the pancreas slowly loses the ability to produce enough insulin, and as a result, the cells don’t get the energy they need to function properly.

Type 1 diabetes occurs when the immune system attacks and destroys the insulin-producing cells in the pancreas (the beta cells). As a result, the body is left without enough insulin to function normally (i.e. it becomes insulin deficient). This is called an autoimmune reaction, because the body attacks itself and produces antibodies to its own insulin-producing cells, thereby destroying them.
A second theory, dubbed the hygiene hypothesis, blames the rise of type 1 on a society that's too clean. Good housekeeping and hygiene habits mean far fewer interactions with germs, which in turn may foster an immune system prone to going awry. "In a developing country, you have more infectious disease. This is associated with a lower risk of type 1 diabetes," says Li Wen, MD, PhD, an immunologist at the Yale University School of Medicine. In her lab, rodents raised in hyper-clean environments are more likely to get type 1 than those reared in dirtier cages.
You have a higher risk of type 2 diabetes if you are older, have obesity, have a family history of diabetes, or do not exercise. Having prediabetes also increases your risk. Prediabetes means that your blood sugar is higher than normal but not high enough to be called diabetes. If you are at risk for type 2 diabetes, you may be able to delay or prevent developing it by making some lifestyle changes.
A second oral agent of another class or insulin may be added if metformin is not sufficient after three months.[76] Other classes of medications include: sulfonylureas, thiazolidinediones, dipeptidyl peptidase-4 inhibitors, SGLT2 inhibitors, and glucagon-like peptide-1 analogs.[76] As of 2015 there was no significant difference between these agents.[76] A 2018 review found that SGLT2 inhibitors may be better than glucagon-like peptide-1 analogs or dipeptidyl peptidase-4 inhibitors.[92]
While there are competing explanations of the link between obesity and type 2 diabetes, Gerald Shulman, MD, PhD, a professor of internal medicine and physiology at Yale University, believes the key is figuring out insulin resistance. He has studied the causes of insulin resistance for 25 years and thinks he may have the answer to the weight-diabetes link.

A positive result, in the absence of unequivocal high blood sugar, should be confirmed by a repeat of any of the above methods on a different day. It is preferable to measure a fasting glucose level because of the ease of measurement and the considerable time commitment of formal glucose tolerance testing, which takes two hours to complete and offers no prognostic advantage over the fasting test.[66] According to the current definition, two fasting glucose measurements above 7.0 mmol/l (126 mg/dl) is considered diagnostic for diabetes mellitus.


The ADA recommends using patient age as one consideration in the establishment of glycemic goals, with different targets for preprandial, bedtime/overnight, and hemoglobin A1c (HbA1c) levels in patients aged 0-6, 6-12, and 13-19 years. [4] Benefits of tight glycemic control include not only continued reductions in the rates of microvascular complications but also significant differences in cardiovascular events and overall mortality.
Diet and moderate exercise are the first treatments implemented in diabetes. For many Type II diabetics, weight loss may be an important goal in helping them to control their diabetes. A well-balanced, nutritious diet provides approximately 50-60% of calories from carbohydrates, approximately 10-20% of calories from protein, and less than 30% of calories from fat. The number of calories required by an individual depends on age, weight, and activity level. The calorie intake also needs to be distributed over the course of the entire day so surges of glucose entering the blood system are kept to a minimum.
To treat diabetic retinopathy, a laser is used to destroy and prevent the recurrence of the development of these small aneurysms and brittle blood vessels. Approximately 50% of patients with diabetes will develop some degree of diabetic retinopathy after 10 years of diabetes, and 80% retinopathy after 15 years of the disease. Poor control of blood sugar and blood pressure further aggravates eye disease in diabetes.
While it's conceivable that scientists will isolate a single factor as causing type 1 and type 2, the much more likely outcome is that there is more than one cause. Each person seems to take a unique path in developing diabetes. Someday, doctors may be able to assess an individual's genetic risk for diabetes, allowing him or her to dodge the particular environmental factors that would trigger the disease. And perhaps if the baffling question of why a person gets diabetes can be put to rest, the answer will also offer a cure for the disease.
Type 2 diabetes is one of the major degenerative diseases in the Western world today. It happens when your body can’t use insulin properly, or can’t make enough insulin. Insulin is a hormone the assists the body’s cells in utilizing glucose. It also helps the body store extra sugar in fat, liver, and muscle cells. If you don’t have insulin, your body can’t use the sugar in the bloodstream.

Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.


Hyperglycemic hyperosmolar nonketotic syndrome (HHNS). Signs and symptoms of this life-threatening condition include a blood sugar reading higher than 600 mg/dL (33.3 mmol/L), dry mouth, extreme thirst, fever greater than 101 F (38 C), drowsiness, confusion, vision loss, hallucinations and dark urine. Your blood sugar monitor may not be able to give you an exact reading at such high levels and may instead just read "high."
Doctors and people with diabetes have observed that infections seem more common if you have diabetes. Research in this area, however, has not proved whether this is entirely true, nor why. It may be that high levels of blood sugar impair your body's natural healing process and your ability to fight infections. For women, bladder and vaginal infections are especially common.
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.
a complex disorder of carbohydrate, fat, and protein metabolism that is primarily a result of a deficiency or complete lack of insulin secretion by the beta cells of the pancreas or resistance to insulin. The disease is often familial but may be acquired, as in Cushing's syndrome, as a result of the administration of excessive glucocorticoid. The various forms of diabetes have been organized into categories developed by the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus of the American Diabetes Association. Type 1 diabetes mellitus in this classification scheme includes patients with diabetes caused by an autoimmune process, dependent on insulin to prevent ketosis. This group was previously called type I, insulin-dependent diabetes mellitus, juvenile-onset diabetes, brittle diabetes, or ketosis-prone diabetes. Patients with type 2 diabetes mellitus are those previously designated as having type II, non-insulin-dependent diabetes mellitus, maturity-onset diabetes, adult-onset diabetes, ketosis-resistant diabetes, or stable diabetes. Those with gestational diabetes mellitus are women in whom glucose intolerance develops during pregnancy. Other types of diabetes are associated with a pancreatic disease, hormonal changes, adverse effects of drugs, or genetic or other anomalies. A fourth subclass, the impaired glucose tolerance group, also called prediabetes, includes persons whose blood glucose levels are abnormal although not sufficiently above the normal range to be diagnosed as having diabetes. Approximately 95% of the 18 million diabetes patients in the United States are classified as type 2, and more than 70% of those patients are obese. About 1.3 million new cases of diabetes mellitus are diagnosed in the United States each year. Contributing factors to the development of diabetes are heredity; obesity; sedentary life-style; high-fat, low-fiber diets; hypertension; and aging. See also impaired glucose tolerance, potential abnormality of glucose tolerance, previous abnormality of glucose tolerance.
Diabetes mellitus has been recorded in all species but is most commonly seen in middle-aged to older, obese, female dogs. A familial predisposition has been suggested. It is possible to identify two types of diabetes, corresponding to the disease in humans, depending on the response to an intravenous glucose tolerance test. Type I is insulin-dependent and comparable to the juvenile onset form of the disease in children in which there is an absolute deficiency of insulin—there is a very low initial blood insulin level and a low response to the injected glucose. This form is seen in a number of dog breeds, particularly the Keeshond, Doberman pinscher, German shepherd dog, Poodle, Golden retriever and Labrador retriever.
Exposure to certain viral infections (mumps and Coxsackie viruses) or other environmental toxins may serve to trigger abnormal antibody responses that cause damage to the pancreas cells where insulin is made. Some of the antibodies seen in type 1 diabetes include anti-islet cell antibodies, anti-insulin antibodies and anti-glutamic decarboxylase antibodies. These antibodies can be detected in the majority of patients, and may help determine which individuals are at risk for developing type 1 diabetes.

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.[37] All of these genes together still only account for 10% of the total heritable component of the disease.[37] 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]
diabetes mel´litus a broadly applied term used to denote a complex group of syndromes that have in common a disturbance in the oxidation and utilization of glucose, which may be secondary to a malfunction of the beta cells of the pancreas, whose function is the production and release of insulin. Because insulin is involved in the metabolism of carbohydrates, proteins, and fats, diabetes is not limited to a disturbance of glucose homeostasis alone. Insulin resistance may also sometimes play a role in the etiology of diabetes. 

High blood sugar (hyperglycemia). Your blood sugar level can rise for many reasons, including eating too much, being sick or not taking enough glucose-lowering medication. Check your blood sugar level often, and watch for signs and symptoms of high blood sugar — frequent urination, increased thirst, dry mouth, blurred vision, fatigue and nausea. If you have hyperglycemia, you'll need to adjust your meal plan, medications or both.

Type 2 diabetes is different. A person with type 2 diabetes still produces insulin but the body doesn't respond to it normally. Glucose is less able to enter the cells and do its job of supplying energy (a problem called insulin resistance). This raises the blood sugar level, so the pancreas works hard to make even more insulin. Eventually, this strain can make the pancreas unable to produce enough insulin to keep blood sugar levels normal.


DM is a strong independent predictor of short- and long-term recurrent ischemic events, including mortality, in acute coronary syndrome (ACS),6,7 including unstable angina and non-ST-elevation MI (NSTEMI),8 ST-elevation MI (STEMI) treated medically,9 and ACS undergoing percutaneous coronary intervention (PCI).10,11 Furthermore, the concomitant presence of cardiovascular risk factors and comorbidities that negatively affect the outcomes of ACS is higher in DM patients.12
People with these risk factors should be screened for diabetes at least once every three years. Diabetes risk can be estimated using online risk calculators. Doctors may measure fasting blood glucose levels and hemoglobin A1C level, or do an oral glucose tolerance test. If the test results are on the border between normal and abnormal, doctors do the screening tests more often, at least once a year.
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.[123]
Beta cells are vulnerable to more than just bad genes, which may explain the associations between type 2 diabetes and environmental factors that aren't related to how much fat a body has or where it is stored. Beta cells carry vitamin D receptors on their surface, and people with vitamin D deficiency are at increased risk for type 2. Plus, several studies have shown that people with higher levels of toxic substances in their blood—such as from the PCBs found in fish fat—are at increased risk of type 2 diabetes, though a cause-and-effect relationship hasn't been proved. (Toxic substances and vitamin D have also been implicated in type 1 diabetes, but the disease mechanism may be unrelated to what's going on in type 2.)

A metabolic disease in which carbohydrate use is reduced and that of lipid and protein enhanced; it is caused by an absolute or relative deficiency of insulin and is characterized, in more severe cases, by chronic hyperglycemia, glycosuria, water and electrolyte loss, ketoacidosis, and coma; long-term complications include neuropathy, retinopathy, nephropathy, generalized degenerative changes in large and small blood vessels, and increased susceptibility to infection.


Despite our efforts, patients are still likely to suffer myocardial infarction. The Diabetes mellitus, Insulin Glucose infusion in Acute Myocardial Infarction (DIGAMI) study236,237 reported on treating subjects with acute myocardial infarction and either diabetes or raised random plasma glucose (i.e., not necessarily diabetic) with either an intensive insulin infusion and then a four-times daily insulin regimen or conventional treatment. Over a mean follow-up of 3.4 years, there was a 33% death rate in the treatment group compared with a 44% death rate in the control group, an absolute reduction in mortality of 11%. The effect was greatest among the subgroup without previous insulin treatment and at a low cardiovascular risk. Evidence is continuing to accumulate that the diabetic person should have a glucose/insulin infusion after a myocardial infarction.
The American Diabetes Association sponsored an international panel in 1995 to review the literature and recommend updates of the classification of diabetes mellitus. The definitions and descriptions that follow are drawn from the Report of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus. The report was first approved in 1997 and modified in 1999. Although other terms are found in older literature and remain in use, their use in current clinical practice is inappropriate. Epidemiologic and research studies are facilitated by use of a common language.
If you are at increased risk of diabetes, have symptoms of diabetes, or have pre-diabetes (a major warning sign for diabetes), your doctor will check to see if you have diabetes. Your doctor may also check to see if you have diabetes if you are over the age of 45, have a family history of the disease, are overweight, or if you are at increased risk for another reason. The tests used to check for diabetes are the same tests used to check for pre-diabetes.
Doctors may recommend one or more types of medications to help control diabetes. While taking medications, it's important for people with diabetes to regularly test their blood glucose levels at home. There are many different blood glucose meters available on the market. Speak to a doctor or pharmacist about these meters to help you select the best meter for your needs.
A1C: Your A1C, also called glycated hemoglobin, reflects your average blood glucose levels for the past 2 to 3 months. If your A1C is 6.5% or greater, your doctor may diagnose diabetes. If your A1C is between 6.0% and 6.4%, your doctor may diagnose prediabetes. Of note, A1C cannot be used to diagnose type 1 diabetes, diabetes in children, adolescents, or pregnant women.

Apart from these medications, treating diabetes effectively means taking a well-rounded approach: You’ll need to eat well, exercise, and manage stress, because all these factors can affect your blood sugar levels. Staying healthy with diabetes also requires caring for yourself — like protecting your feet, practicing oral hygiene, and tending to your mental health.
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]
Diabetes was one of the first diseases described,[107] with an Egyptian manuscript from c. 1500 BCE mentioning "too great emptying of the urine".[108] The Ebers papyrus includes a recommendation for a drink to be taken in such cases.[109] The first described cases are believed to be of type 1 diabetes.[108] Indian physicians around the same time identified the disease and classified it as madhumeha or "honey urine", noting the urine would attract ants.[108][109]
Another less common form is gestational diabetes, a temporary condition that occurs during pregnancy. Depending on risk factors, between 3% to 13% of Canadian women will develop gestational diabetes which can be harmful for the baby if not controlled. The problem usually clears up after delivery, but women who have had gestational diabetes have a higher risk of developing type 2 diabetes later in life.
For example, the environmental trigger may be a virus or chemical toxin that upsets the normal function of the immune system. This may lead to the body’s immune system attacking itself. The normal beta cells in the pancreas may be attacked and destroyed. When approximately 90% of the beta cells are destroyed, symptoms of diabetes mellitus begin to appear. The exact cause and sequence is not fully understood but investigation and research into the disease continues.
Indigestion (dyspepsia) can be caused by diseases or conditions that involve the gastrointestinal (GI) tract, and also by some diseases and conditions that do not involve the GI tract. Indigestion can be a chronic condition in which the symptoms fluctuate infrequency and intensity. Signs and symptoms that accompany indigestion include pain in the chest, upper abdominal pain, belching, nausea, bloating, abdominal distention, feeling full after eating only a small portion of food, and rarely, vomiting.
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