Pre-clinical diabetes refers to the time during which destruction of pancreatic insulin-producing cells is occurring, but symptoms have not yet developed. This period may last for months to years. Normally, 80-90% of the pancreatic beta cells must be destroyed before any symptoms of diabetes develops. During this time, blood tests can identify some immunological markers of pancreatic cell destruction. However, there is currently no known treatment to prevent progression of pre-clinical diabetes to true diabetes mellitus.
It’s not uncommon for patients to suddenly feel unsteady and immediately need to reach for carbs, says Marjorie Cypress, a nurse practitioner at an endocrinology clinic in Albuquerque, New Mexico, and 2014 president of health care and education for the American Diabetes Association. “When you have high blood sugar, your body has a problem regulating its glucose,” she explains. “If you’ve eaten something high in carbohydrates, your body shoots out a little too much insulin, and your glucose drops quickly. This makes you feel shaky, and you tend to crave carbs or sugar. This can lead to a vicious cycle.” These are the best foods for someone on a diabetic diet.
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.

When your blood sugar is out of whack, you just don’t feel well, says Cypress, and might become more short-tempered. In fact, high blood sugar can mimic depression-like symptoms. “You feel very tired, you don’t feel like doing anything, you don’t want to go out, you just want to sleep,” Cypress says. She’ll see patients who think they need to be treated for depression, but then experience mood improvement after their blood sugar normalizes.
The beta cells may be another place where gene-environment interactions come into play, as suggested by the previously mentioned studies that link beta cell genes with type 2. "Only a fraction of people with insulin resistance go on to develop type 2 diabetes," says Shulman. If beta cells can produce enough insulin to overcome insulin resistance, a factor that may be genetically predetermined, then a person can stay free of diabetes. But if the beta cells don't have good genes propping them up, then diabetes is the more likely outcome in a person with substantial insulin resistance.

Examples of simple or refined carbohydrates, on the other hand, exist in various forms — from the sucrose in the table sugar you use to bake cookies, to the various kinds of added sugar in packaged snacks, fruit drinks, soda, and cereal. Simple carbohydrates are natural components of many fresh foods, too, such as the lactose in milk and the fructose in fruits, and therefore, a healthy, well-balanced diet will always contain these types of sugars.
The most common complication of treating high blood glucose levels is low blood glucose levels (hypoglycemia). The risk is greatest for older people who are frail, who are sick enough to require frequent hospital admissions, or who are taking several drugs. Of all available drugs to treat diabetes, long-acting sulfonylurea drugs are most likely to cause low blood glucose levels in older people. When they take these drugs, they are also more likely to have serious symptoms, such as fainting and falling, and to have difficulty thinking or using parts of the body due to low blood glucose levels.

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]

Many studies have shown that awareness about the diabetes and its complications is poor among the general population specially in the rural areas6,7. There is an urgent need to create awareness among the population regarding diabetes and about the serious consequences of this chronic disorder. Epidemiological data from India have shown the presence of a number of risk factors which can be easily identified by simple non-invasive risk scores8,9. The major risk factors are listed in Box 1.
Insulin — the hormone that allows your body to regulate sugar in the blood — is made in your pancreas. Essentially, insulin resistance is a state in which the body’s cells do not use insulin efficiently. As a result, it takes more insulin than normal to transport blood sugar (glucose) into cells, to be used immediately for fuel or stored for later use. A drop in efficiency in getting glucose to cells creates a problem for cell function; glucose is normally the body’s quickest and most readily available source of energy.

Insulin is a hormone that is produced by specialized cells (beta cells) of the pancreas. (The pancreas is a deep-seated organ in the abdomen located behind the stomach.) In addition to helping glucose enter the cells, insulin is also important in tightly regulating the level of glucose in the blood. After a meal, the blood glucose level rises. In response to the increased glucose level, the pancreas normally releases more insulin into the bloodstream to help glucose enter the cells and lower blood glucose levels after a meal. When the blood glucose levels are lowered, the insulin release from the pancreas is turned down. It is important to note that even in the fasting state there is a low steady release of insulin than fluctuates a bit and helps to maintain a steady blood sugar level during fasting. In normal individuals, such a regulatory system helps to keep blood glucose levels in a tightly controlled range. As outlined above, in patients with diabetes, the insulin is either absent, relatively insufficient for the body's needs, or not used properly by the body. All of these factors cause elevated levels of blood glucose (hyperglycemia).

Over recent decades, and particularly in the past five years, researchers have found dozens of genes with links to diabetes. The count stands at about 50 genes for type 1 and 38 for type 2. The numbers have risen quickly in recent years because of advances in the gene-sequencing technology used to conduct genome-wide association studies. This technique involves taking the genetic compositions of a group of people with a disease and comparing them en masse to the genomes of people who don't have the disease.
Diabetes mellitus (“diabetes”) and hypertension, which commonly coexist, are global public health issues contributing to an enormous burden of cardiovascular disease, chronic kidney disease, and premature mortality and disability. The presence of both conditions has an amplifying effect on risk for microvascular and macrovascular complications.1 The prevalence of diabetes is rising worldwide (Fig. 37.1). Both diabetes and hypertension disproportionately affect people in middle and low-income countries, and an estimated 70% of all cases of diabetes are found in these countries.2,3 In the United States alone, the total costs of care for diabetes and hypertension in the years 2012 and 2011 were 245 and 46 billion dollars, respectively.4,5 Therefore, there is a great potential for meaningful health and economic gains attached to prevention, detection, and intervention for diabetes and hypertension.
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The problem with sweetened drinks is that, due to their liquid form, they’re among the fastest simple carbs to be digested in the body, causing blood sugar levels to spike even more than a simple carb in solid-food form would. Research supports this idea: A review published in November 2010 in the journal Diabetes Care suggested adding only one serving of a sweetened beverage to your diet may increase your risk for type 2 diabetes by 15 percent.
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.
Rosiglitazone, a thiazolidinedione, has not been found to improve long-term outcomes even though it improves blood sugar levels.[93] Additionally it is associated with increased rates of heart disease and death.[94] Angiotensin-converting enzyme inhibitors (ACEIs) prevent kidney disease and improve outcomes in those with diabetes.[95][96] The similar medications angiotensin receptor blockers (ARBs) do not.[96] A 2016 review recommended treating to a systolic blood pressure of 140 to 150 mmHg.[97]

Although age of onset and length of the disease process are related to the frequency with which vascular, renal, and neurologic complications develop, there are some patients who remain relatively free of sequelae even into the later years of their lives. Because diabetes mellitus is not a single disease but rather a complex constellation of syndromes, each patient has a unique response to the disease process.
a chronic metabolic disorder in which the use of carbohydrate is impaired and that of lipid and protein is 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.
What his theory boils down to is that type 2 diabetes is caused not by extra fat alone, but by fat stored in the wrong places. "Virtually all the individuals [with insulin resistance] have fat accumulation in liver and muscle," Shulman says, where it may disrupt normal biological processes, leading to insulin resistance. "If you can understand this, you can ideally come up with new ways to prevent insulin resistance and type 2 diabetes."
Injections of insulin may either be added to oral medication or used alone.[24] Most people do not initially need insulin.[13] When it is used, a long-acting formulation is typically added at night, with oral medications being continued.[23][24] Doses are then increased to effect (blood sugar levels being well controlled).[24] When nightly insulin is insufficient, twice daily insulin may achieve better control.[23] The long acting insulins glargine and detemir are equally safe and effective,[98] and do not appear much better than neutral protamine Hagedorn (NPH) insulin, but as they are significantly more expensive, they are not cost effective as of 2010.[99] In those who are pregnant insulin is generally the treatment of choice.[23]
Different environmental effects on type 1 diabetes mellitus development complicate the influence of race, but racial differences are evident. Whites have the highest reported incidence, whereas Chinese individuals have the lowest. Type 1 diabetes mellitus is 1.5 times more likely to develop in American whites than in American blacks or Hispanics. Current evidence suggests that when immigrants from an area with low incidence move to an area with higher incidence, their rates of type 1 diabetes mellitus tend to increase toward the higher level.

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.


So what determines where fat is stored, and thus a person's propensity for insulin resistance and type 2 diabetes? Well, just having more fat in the body increases the risk that some of it will get misplaced. But exercise may also have a role in fat placement. Exercise is known to reduce insulin resistance; one way it may do this is by burning fat out of the muscle. Because of this, getting enough exercise may stave off type 2 in some cases. Genes may also help orchestrate the distribution of fat in the body, which illustrates how lifestyle and genetics interact.
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.
The classic presenting symptoms of type 1 diabetes mellitus are discussed below. For some children, the first symptoms of diabetes mellitus are those of diabetic ketoacidosis. This is a serious and life-threatening condition, requiring immediate treatment. Ketoacidosis occurs due to a severe disturbance in the body’s metabolism. Without insulin, glucose cannot be taken up into cells. Instead fats are broken down for energy which can have acid by-products.  
Diabetes mellitus is a disorder in which the amount of sugar in the blood is elevated. Doctors often use the full name diabetes mellitus, rather than diabetes alone, to distinguish this disorder from diabetes insipidus. Diabetes insipidus is a relatively rare disorder that does not affect blood glucose levels but, just like diabetes mellitus, also causes increased urination.

Type 1 diabetes has some connection to your family genes, but that doesn't mean you'll get it if one of your parents had it. "Since not all identical twins get diabetes, we do think that exposure to an additional environmental factor may trigger an immune response that ultimately causes destruction of the insulin-producing cells of the pancreas," says Dr. Sarah R. Rettinger, an endocrinologist with Providence Saint John's Health Center in Santa Monica, California.
Which came first: the diabetes or the PCOS? For many women, a diagnosis of polycystic ovary syndrome means a diabetes diagnosis isn’t far behind. PCOS and diabetes are both associated with insulin resistance, meaning there are similar hormonal issues at play in both diseases. Fortunately, managing your PCOS and losing weight may help reduce your risk of becoming diabetic over time.

After a diagnosis of diabetes mellitus has been made, and treatment with insulin therapy has begun, a so-called ‘honeymoon stage’ may develop. This stage is characterised by a reduction in insulin requirements which may last from weeks to months. Some patients may require no insulin at all. This stage is always transient (short-lasting) and is due to production of insulin by the remaining surviving pancreatic beta cells. Eventually, these cells will be destroyed by the on-going auto-immune process, and the patient will be dependent on exogenous (artificial) insulin.


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.

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]
People usually develop type 2 diabetes after the age of 40 years, although people of South Asian origin are at an increased risk of the condition and may develop diabetes from the age of 25 onwards. The condition is also becoming increasingly common among children and adolescents across all populations. Type 2 diabetes often develops as a result of overweight, obesity and lack of physical activity and diabetes prevalence is on the rise worldwide as these problems become more widespread.
Diabetes mellitus (diabetes) is a common chronic disease of abnormal carbohydrate, fat, and protein metabolism that affects an estimated 20 million people in the United States, of whom about one third are undiagnosed. There are two major forms recognized, type-1 and type-2. Both are characterized by inappropriately high blood sugar levels (hyperglycemia). In type-1 diabetes the patient can not produce the hormone insulin, while in type-2 diabetes the patient produces insulin, but it is not used properly. An estimated 90% of diabetic patients suffer from type-2 disease. The causes of diabetes are multiple and both genetic and environmental factors contribute to its development. The genetic predisposition for type-2 diabetes is very strong and numerous environmental factors such as diet, lack of exercise, and being overweight are known to also increase one’s risk for diabetes. Diabetes is a dangerous disease which affects the entire body and diabetic patients are at increased risk for heart disease, hypertension, stroke, kidney failure, blindness, neuropathy, and infection when compared to nondiabetic patients. Diabetic patients also have impaired healing when compared to healthy individuals. This is in part due to the dysfunction of certain white blood cells that fight infection.
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]
Not all people with diabetes need drug therapy. A healthy eating plan and exercise alone can be enough if the person makes significant lifestyle changes. Other signs, symptoms, and complications also may need treatment. For example, nutritional deficiencies should be corrected, heart or kidney disease may need to be treated, and vision must be checked for eye problems like diabetic retinopathy.
Medications used to treat diabetes do so by lowering blood sugar levels. There is broad consensus that when people with diabetes maintain tight glucose control (also called "tight glycemic control") -- keeping the glucose levels in their blood within normal ranges - that they experience fewer complications like kidney problems and eye problems.[84][85] There is however debate as to whether this is cost effective for people later in life.[86]

Diabetes can also result from other hormonal disturbances, such as excessive growth hormone production (acromegaly) and Cushing's syndrome. In acromegaly, a pituitary gland tumor at the base of the brain causes excessive production of growth hormone, leading to hyperglycemia. In Cushing's syndrome, the adrenal glands produce an excess of cortisol, which promotes blood sugar elevation.
There is evidence that certain emotions can promote type 2 diabetes. A recent study found that depression seems to predispose people to diabetes. Other research has tied emotional stress to diabetes, though the link hasn't been proved. Researchers speculate that the emotional connection may have to do with the hormone cortisol, which floods the body during periods of stress. Cortisol sends glucose to the blood, where it can fuel a fight-or-flight response, but overuse of this system may lead to dysfunction.

A study by Mayer-Davis et al indicated that between 2002 and 2012, the incidence of type 1 and type 2 diabetes mellitus saw a significant rise among youths in the United States. According to the report, after the figures were adjusted for age, sex, and race or ethnic group, the incidence of type 1 (in patients aged 0-19 years) and type 2 diabetes mellitus (in patients aged 10-19 years) during this period underwent a relative annual increase of 1.8% and 4.8%, respectively. The greatest increases occurred among minority youths. [29]
Manage mild hypoglycemia by giving rapidly absorbed oral carbohydrate or glucose; for a comatose patient, administer an intramuscular injection of the hormone glucagon, which stimulates the release of liver glycogen and releases glucose into the circulation. Where appropriate, an alternative therapy is intravenous glucose (preferably no more than a 10% glucose solution). All treatments for hypoglycemia provide recovery in approximately 10 minutes. (See Treatment.)
Viral infections may be the most important environmental factor in the development of type 1 diabetes mellitus, [26] probably by initiating or modifying an autoimmune process. Instances have been reported of a direct toxic effect of infection in congenital rubella. One survey suggests enteroviral infection during pregnancy carries an increased risk of type 1 diabetes mellitus in the offspring. Paradoxically, type 1 diabetes mellitus incidence is higher in areas where the overall burden of infectious disease is lower.
Prediabetes is a condition in which blood glucose levels are higher than normal, but a person does not yet have diabetes. Prediabetes and high blood glucose levels are a risk factor for developing diabetes, heart disease, and other health problems. Other warning signs prediabetes may include increased urination, feeling you need to urinate more often, and/or increased thirst.
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