People with type 2 diabetes have insulin resistance, which means the body cannot use insulin properly to help glucose get into the cells. In people with type 2 diabetes, insulin doesn’t work well in muscle, fat, and other tissues, so your pancreas (the organ that makes insulin) starts to put out a lot more of it to try and compensate. "This results in high insulin levels in the body,” says Fernando Ovalle, MD, director of the multidisciplinary diabetes clinic at the University of Alabama in Birmingham. This insulin level sends signals to the brain that your body is hungry.
The term "diabetes" or "to pass through" was first used in 230 BCE by the Greek Apollonius of Memphis. The disease was considered rare during the time of the Roman empire, with Galen commenting he had only seen two cases during his career. This is possibly due to the diet and lifestyle of the ancients, or because the clinical symptoms were observed during the advanced stage of the disease. Galen named the disease "diarrhea of the urine" (diarrhea urinosa).
Type 2 diabetes, a form of diabetes mellitus, is likely one of the better-known chronic diseases in the world — and that's no surprise. Data from the Centers for Disease Control and Prevention suggest in the United States alone, 30.3 million people, or 9.4 percent of the U.S. population, has diabetes, and the majority of these people have type 2. (1)
It is also important to note that currently one third of those who have IGT are in the productive age between 20-39 yr and, therefore, are likely to spend many years at high risk of developing diabetes and/or complications of diabetes1. Some persons with prediabetes experience reactive hypoglycaemia 2-3 hours after a meal. This is a sign of impaired insulin metabolism indicative of impending occurrence of diabetes. Therefore, periodic medical check-up in people with such signs or risk factors for diabetes would reduce the hazards involved in having undiagnosed diabetes. It would help improve the health status of a large number of people who otherwise would be silent sufferers from the metabolic aberrations associated with diabetes.
Diabetes has been coined the “silent killer” because the symptoms are so easy to miss. Over 24 million people in America have diabetes, so this is no tiny issue. Kids years ago hardly ever knew another child with diabetes, but such is no longer the case. Approximately 1.25 million children in the United States living with diabetes, which is very telling for state of health in America in 2016 when children are having to endure a medical lifestyle at such a young age.
Type 1 diabetes mellitus has wide geographic variation in incidence and prevalence.  Annual incidence varies from 0.61 cases per 100,000 population in China to 41.4 cases per 100,000 population in Finland. Substantial variations are observed between nearby countries with differing lifestyles, such as Estonia and Finland, and between genetically similar populations, such as those in Iceland and Norway.
The blood vessels and blood are the highways that transport sugar from where it is either taken in (the stomach) or manufactured (in the liver) to the cells where it is used (muscles) or where it is stored (fat). Sugar cannot go into the cells by itself. The pancreas releases insulin into the blood, which serves as the helper, or the "key," that lets sugar into the cells for use as energy.
Type 1 diabetes in pediatric patients has been linked to changes in cognition and brain structure, with a study by Siller et al finding lower volume in the left temporal-parietal-occipital cortex in young patients with type 1 diabetes than in controls. The study also indicated that in pediatric patients, higher severity of type 1 diabetes presentation correlates with greater structural differences in the brain at about 3 months following diagnosis. The investigators found that among study patients with type 1 diabetes, an association existed between the presence of diabetic ketoacidosis at presentation and reduced radial, axial, and mean diffusivity in the major white matter tracts on magnetic resonance imaging (MRI). In those with higher glycated hemoglobin (HbA1c) levels, hippocampal, thalamic, and cerebellar white matter volumes were lower, as was right posterior parietal cortical thickness, while right occipital cortical thickness was greater. Patients in the study were aged 7-17 years. 
Though not routinely used any longer, the oral glucose tolerance test (OGTT) is a gold standard for making the diagnosis of type 2 diabetes. It is still commonly used for diagnosing gestational diabetes and in conditions of pre-diabetes, such as polycystic ovary syndrome. With an oral glucose tolerance test, the person fasts overnight (at least eight but not more than 16 hours). Then first, the fasting plasma glucose is tested. After this test, the person receives an oral dose (75 grams) of glucose. There are several methods employed by obstetricians to do this test, but the one described here is standard. Usually, the glucose is in a sweet-tasting liquid that the person drinks. Blood samples are taken at specific intervals to measure the blood glucose.
American Diabetes Association Joslin Diabetes Center Mayo Clinic International Diabetes Federation Canadian Diabetes Association National Institute of Diabetes and Digestive and Kidney Diseases Diabetes Daily American Heart Association Diabetes Forecast Diabetic Living American Association of Clinical Endocrinologists European Association for the Study of Diabetes
The good news is that prevention plays an important role in warding off these complications. By maintaining tight control of your blood glucose—and getting it as close to normal as possible—you’ll help your body function in the way that it would if you did not have diabetes. Tight control helps you decrease the chances that your body will experience complications from elevated glucose levels.
The roots of type 2 diabetes remain in insulin resistance and pancreatic failure, and the blame for the current diabetes epidemic lies in an overall dietary pattern emphasizing meat, dairy products, and fatty foods, aided and abetted by sugary foods and beverages, rather than simply in sugar alone. A diet emphasizing vegetables, fruits, whole grains, and legumes and avoiding animal products helps prevent diabetes and improves its management when it has been diagnosed.
WELL-CONTROLLED DIABETES MELLITUS: Daily blood sugar abstracted from the records of a patient whose DM is well controlled (hemoglobin A1c=6.4). The average capillary blood glucose level is 104 mg/dL, and the standard deviation is 19. Sixty-five percent of the readings are between 90 and 140 mg/dL; the lowest blood sugar is 67 mg/dL (on April 15) and the highest is about 190 (on March 21).
Type 2 diabetes is mainly caused by insulin resistance. This means no matter how much or how little insulin is made, the body can't use it as well as it should. As a result, glucose can't be moved from the blood into cells. Over time, the excess sugar in the blood gradually poisons the pancreas causing it to make less insulin and making it even more difficult to keep blood glucose under control.
Hypoglycemia, or low blood sugar, can be caused by too much insulin, too little food (or eating too late to coincide with the action of the insulin), alcohol consumption, or increased exercise. A patient with symptoms of hypoglycemia may be hungry, cranky, confused, and tired. The patient may become sweaty and shaky. Left untreated, the patient can lose consciousness or have a seizure. This condition is sometimes called an insulin reaction and should be treated by giving the patient something sweet to eat or drink like a candy, sugar cubes, juice, or another high sugar snack.
“I don’t think that anybody has put their finger on what the true cause of diabetes is, or that we’re going to find a single cause,” Grieger says. So if you’ve been diagnosed with prediabetes or have other risk factors for the disease, avoiding any one food group entirely — even sugar — won’t completely offset your risk. Rather, it’s important to prioritize proper nutrition, exercise regularly, and maintain a healthy weight — all steps the American Diabetes Association recommends for preventing type 2 diabetes.
Type 2 DM begins with insulin resistance, a condition in which cells fail to respond to insulin properly. As the disease progresses, a lack of insulin may also develop. This form was previously referred to as "non insulin-dependent diabetes mellitus" (NIDDM) or "adult-onset diabetes". The most common cause is excessive body weight and insufficient exercise.
Though it may be transient, untreated GDM can damage the health of the fetus or mother. Risks to the baby include macrosomia (high birth weight), congenital heart and central nervous system abnormalities, and skeletal muscle malformations. Increased levels of insulin in a fetus's blood may inhibit fetal surfactant production and cause infant respiratory distress syndrome. A high blood bilirubin level may result from red blood cell destruction. In severe cases, perinatal death may occur, most commonly as a result of poor placental perfusion due to vascular impairment. Labor induction may be indicated with decreased placental function. A caesarean section may be performed if there is marked fetal distress or an increased risk of injury associated with macrosomia, such as shoulder dystocia.
Type 2 diabetes is often treated with oral medication because many people with this type of diabetes make some insulin on their own. The pills people take to control type 2 diabetes do not contain insulin. Instead, medications such as metformin, sulfonylureas, alpha-glucosidase inhibitors and many others are used to make the insulin that the body still produces more effective.
The woman’s weight may also play a role. Changing hormone levels and weight gain are part of a healthy pregnancy, but both changes make it more difficult for the body to keep up with its need for insulin. This may lead to gestational diabetes. As pregnancy progresses, the placenta also produces insulin-blocking hormones, which might result in a woman’s blood-glucose levels becoming elevated if there isn’t enough insulin to counter this effect.
Blood glucose levels: persistently elevated blood sugar levels are diagnostic of diabetes mellitus. A specific test called a glucose tolerance test (GTT) may be performed. For this you need to be fasted and will be given a sugary drink. Your glucose level will then be measured at one and two hours after the doseto determine how welll your body copes with glucose.
Cataracts and glaucoma are also more common among diabetics. It is also important to note that since the lens of the eye lets water through, if blood sugar concentrations vary a lot, the lens of the eye will shrink and swell with fluid accordingly. As a result, blurry vision is very common in poorly controlled diabetes. Patients are usually discouraged from getting a new eyeglass prescription until their blood sugar is controlled. This allows for a more accurate assessment of what kind of glasses prescription is required.
Jock itch is an itchy red rash that appears in the groin area. The rash may be caused by a bacterial or fungal infection. People with diabetes and those who are obese are more susceptible to developing jock itch. Antifungal shampoos, creams, and pills may be needed to treat fungal jock itch. Bacterial jock itch may be treated with antibacterial soaps and topical and oral antibiotics.
"We know that there is a very large genetic component," Rettinger says. "A person with a first-degree relative with Type 2 diabetes has a five to 10 time higher risk of developing diabetes than a person the same age and weight without a family history of Type 2 diabetes." Heredity actually plays a larger role in Type 2 diabetes than Type 1, Rettinger says.
Type 2 diabetes usually begins with insulin resistance, a condition in which muscle, liver, and fat cells do not use insulin well. As a result, your body needs more insulin to help glucose enter cells. At first, the pancreas makes more insulin to keep up with the added demand. Over time, the pancreas can’t make enough insulin, and blood glucose levels rise.
Over time, a prolonged exposure to high blood sugar can damage the nerves throughout the body — a condition called diabetic neuropathy. Some people may not have any symptoms of the damage, while others may notice numbness, tingling, or pain in the extremities. “At the beginning, [diabetic neuropathy] usually starts in the feet and then it progresses upward,” says Dr. Ovalle. Although most common in people who have had type 2 diabetes for 25 years or more, it can occur in people who have prediabetes as well. In some studies, almost 50 percent of unexplained peripheral neuropathy [in the extremities], whether painful or otherwise, turns out to be caused by prediabetes or diabetes, says Dr. Einhorn.