Intensive blood sugar lowering (HbA1c<6%) as opposed to standard blood sugar lowering (HbA1c of 7–7.9%) does not appear to change mortality.[78][79] The goal of treatment is typically an HbA1c of 7 to 8% or a fasting glucose of less than 7.2 mmol/L (130 mg/dl); however these goals may be changed after professional clinical consultation, taking into account particular risks of hypoglycemia and life expectancy.[61][80][81] Despite guidelines recommending that intensive blood sugar control be based on balancing immediate harms with long-term benefits, many people – for example people with a life expectancy of less than nine years who will not benefit, are over-treated.[82]
A study by Zheng et al indicated that HbA1c levels in persons with diabetes are longitudinally associated with long-term cognitive decline, as found using a mean 4.9 cognitive assessments of diabetes patients over a mean 8.1-year follow-up period. The investigators saw a significant link between each 1 mmol/mol rise in HbA1c and an increased rate of decline in z scores for global cognition, memory, and executive function. Patients in the study had a mean age of 65.6 years. The report cited a need for research into whether optimal glucose control in people with diabetes can affect their cognitive decline rate. [77, 78]

^ Pignone M, Alberts MJ, Colwell JA, Cushman M, Inzucchi SE, Mukherjee D, Rosenson RS, Williams CD, Wilson PW, Kirkman MS (June 2010). "Aspirin for primary prevention of cardiovascular events in people with diabetes: a position statement of the American Diabetes Association, a scientific statement of the American Heart Association, and an expert consensus document of the American College of Cardiology Foundation". Diabetes Care. 33 (6): 1395–402. doi:10.2337/dc10-0555. PMC 2875463. PMID 20508233.
Erectile dysfunction is the difficulty achieving or maintaining an erection. If you have diabetes, you are 2 – 3 times more likely to have erectile dysfunction compared to men who are well; or experience the problem 10 – 15 years earlier. There is also research that suggests that erectile dysfunction may be an early marker of diabetes, particularly in younger men.

The prognosis in patients with diabetes mellitus is strongly influenced by the degree of control of their disease. Chronic hyperglycemia is associated with an increased risk of microvascular complications, as shown in the Diabetes Control and Complications Trial (DCCT) in individuals with type 1 diabetes [65, 66] and the United Kingdom Prospective Diabetes Study (UKPDS) in people with type 2 diabetes. [67]
^ Rubino F, Nathan DM, Eckel RH, Schauer PR, Alberti KG, Zimmet PZ, Del Prato S, Ji L, Sadikot SM, Herman WH, Amiel SA, Kaplan LM, Taroncher-Oldenburg G, Cummings DE (June 2016). "Metabolic Surgery in the Treatment Algorithm for Type 2 Diabetes: A Joint Statement by International Diabetes Organizations". Diabetes Care. 39 (6): 861–77. doi:10.2337/dc16-0236. PMID 27222544.

Diabetes is a disease that occurs when your blood glucose, also called blood sugar, is too high. Blood glucose is your main source of energy and comes from the food you eat. Insulin, a hormone made by the pancreas, helps glucose from food get into your cells to be used for energy. Sometimes your body doesn’t make enough—or any—insulin or doesn’t use insulin well. Glucose then stays in your blood and doesn’t reach your cells.
In both diabetic and nondiabetic patients, coronary vasodilator dysfunction is a strong independent predictor of cardiac mortality. In diabetic patients without coronary artery disease, those with impaired coronary flow reserve have event rates similar to those with prior coronary artery disease, while patients with preserved coronary flow reserve have event rates similar to nondiabetic patients. [82]
Onset of type 2 diabetes can be delayed or prevented through proper nutrition and regular exercise.[62][63][needs update] Intensive lifestyle measures may reduce the risk by over half.[24][64] The benefit of exercise occurs regardless of the person's initial weight or subsequent weight loss.[65] High levels of physical activity reduce the risk of diabetes by about 28%.[66] Evidence for the benefit of dietary changes alone, however, is limited,[67] with some evidence for a diet high in green leafy vegetables[68] and some for limiting the intake of sugary drinks.[69] There is an association between higher intake of sugar-sweetened fruit juice and diabetes, but no evidence of an association with 100% fruit juice.[70] A 2019 review found evidence of benefit from dietary fiber.[71]
Prevention and treatment involve maintaining a healthy diet, regular physical exercise, a normal body weight, and avoiding use of tobacco.[2] Control of blood pressure and maintaining proper foot care are important for people with the disease.[2] Type 1 diabetes must be managed with insulin injections.[2] Type 2 diabetes may be treated with medications with or without insulin.[13] Insulin and some oral medications can cause low blood sugar.[14] Weight loss surgery in those with obesity is sometimes an effective measure in those with type 2 diabetes.[15] Gestational diabetes usually resolves after the birth of the baby.[16]
Lifestyle factors are important to the development of type 2 diabetes, including obesity and being overweight (defined by a body mass index of greater than 25), lack of physical activity, poor diet, stress, and urbanization.[10][32] Excess body fat is associated with 30% of cases in those of Chinese and Japanese descent, 60–80% of cases in those of European and African descent, and 100% of cases in Pima Indians and Pacific Islanders.[13] Among those who are not obese, a high waist–hip ratio is often present.[13] Smoking appears to increase the risk of type 2 diabetes.[33]
Rates of diabetes in 1985 were estimated at 30 million, increasing to 135 million in 1995 and 217 million in 2005.[18] This increase is believed to be primarily due to the global population aging, a decrease in exercise, and increasing rates of obesity.[18] The five countries with the greatest number of people with diabetes as of 2000 are India having 31.7 million, China 20.8 million, the United States 17.7 million, Indonesia 8.4 million, and Japan 6.8 million.[113] It is recognized as a global epidemic by the World Health Organization.[1]

Type 1 diabetes can occur at any age, and a significant proportion is diagnosed during adulthood. Latent autoimmune diabetes of adults (LADA) is the diagnostic term applied when type 1 diabetes develops in adults; it has a slower onset than the same condition in children. Given this difference, some use the unofficial term "type 1.5 diabetes" for this condition. Adults with LADA are frequently initially misdiagnosed as having type 2 diabetes, based on age rather than cause[46]

The prevalence of type 2 diabetes mellitus varies widely among various racial and ethnic groups. The image below shows data for various populations. Type 2 diabetes mellitus is more prevalent among Hispanics, Native Americans, African Americans, and Asians/Pacific Islanders than in non-Hispanic whites. Indeed, the disease is becoming virtually pandemic in some groups of Native Americans and Hispanic people. The risk of retinopathy and nephropathy appears to be greater in blacks, Native Americans, and Hispanics.

The WHO estimates that diabetes resulted in 1.5 million deaths in 2012, making it the 8th leading cause of death.[13][104] However another 2.2 million deaths worldwide were attributable to high blood glucose and the increased risks of cardiovascular disease and other associated complications (e.g. kidney failure), which often lead to premature death and are often listed as the underlying cause on death certificates rather than diabetes.[104][107] For example, in 2017, the International Diabetes Federation (IDF) estimated that diabetes resulted in 4.0 million deaths worldwide,[9] using modeling to estimate the total number of deaths that could be directly or indirectly attributed to diabetes.[9]

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. 

^ Jump up to: a b Cheng J, Zhang W, Zhang X, Han F, Li X, He X, Li Q, Chen J (May 2014). "Effect of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers on all-cause mortality, cardiovascular deaths, and cardiovascular events in patients with diabetes mellitus: a meta-analysis". JAMA Internal Medicine. 174 (5): 773–85. doi:10.1001/jamainternmed.2014.348. PMID 24687000.


^ Jump up to: a b c Simpson TC, Weldon JC, Worthington HV, Needleman I, Wild SH, Moles DR, Stevenson B, Furness S, Iheozor-Ejiofor Z (November 2015). "Treatment of periodontal disease for glycaemic control in people with diabetes mellitus". The Cochrane Database of Systematic Reviews (11): CD004714. doi:10.1002/14651858.CD004714.pub3. PMC 6486035. PMID 26545069.
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.[69] According to the current definition, two fasting glucose measurements above 7.0 mmol/l (126 mg/dl) is considered diagnostic for diabetes mellitus.
A study by Zheng et al indicated that HbA1c levels in persons with diabetes are longitudinally associated with long-term cognitive decline, as found using a mean 4.9 cognitive assessments of diabetes patients over a mean 8.1-year follow-up period. The investigators saw a significant link between each 1 mmol/mol rise in HbA1c and an increased rate of decline in z scores for global cognition, memory, and executive function. Patients in the study had a mean age of 65.6 years. The report cited a need for research into whether optimal glucose control in people with diabetes can affect their cognitive decline rate. [77, 78]
The top 10 countries in number of people with diabetes are currently India, China, the United States, Indonesia, Japan, Pakistan, Russia, Brazil, Italy, and Bangladesh. The greatest percentage increase in rates of diabetes will occur in Africa over the next 20 years. Unfortunately, at least 80% of people in Africa with diabetes are undiagnosed, and many in their 30s to 60s will die from diabetes there.

^ Jump up to: a b c d Vos T, Allen C, Arora M, Barber RM, Bhutta ZA, Brown A, et al. (GBD 2015 Disease and Injury Incidence and Prevalence Collaborators) (October 2016). "Global, regional, and national incidence, prevalence, and years lived with disability for 310 diseases and injuries, 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015". Lancet. 388 (10053): 1545–1602. doi:10.1016/S0140-6736(16)31678-6. PMC 5055577. PMID 27733282.


The primary complications of diabetes due to damage in small blood vessels include damage to the eyes, kidneys, and nerves.[32] Damage to the eyes, known as diabetic retinopathy, is caused by damage to the blood vessels in the retina of the eye, and can result in gradual vision loss and eventual blindness.[32] Diabetes also increases the risk of having glaucoma, cataracts, and other eye problems. It is recommended that diabetics visit an eye doctor once a year.[33] Damage to the kidneys, known as diabetic nephropathy, can lead to tissue scarring, urine protein loss, and eventually chronic kidney disease, sometimes requiring dialysis or kidney transplantation.[32] Damage to the nerves of the body, known as diabetic neuropathy, is the most common complication of diabetes.[32] The symptoms can include numbness, tingling, pain, and altered pain sensation, which can lead to damage to the skin. Diabetes-related foot problems (such as diabetic foot ulcers) may occur, and can be difficult to treat, occasionally requiring amputation. Additionally, proximal diabetic neuropathy causes painful muscle atrophy and weakness.
Diabetes can also be a finding in more severe mitochondrial disorders such as Kearns-Sayre syndrome and mitochondrial encephalomyopathy, lactic acidosis, and strokelike episode (MELAS). Mitochondrial forms of diabetes mellitus should be considered when diabetes occurs in conjunction with hearing loss, myopathy, seizure disorder, strokelike episodes, retinitis pigmentosa, external ophthalmoplegia, or cataracts. These findings are of particular significance if there is evidence of maternal inheritance.
Diabetes mellitus (DM), commonly known as diabetes, is a group of metabolic disorders characterized by high blood sugar levels over a prolonged period.[10] Symptoms of high blood sugar include frequent urination, increased thirst, and increased hunger.[2] If left untreated, diabetes can cause many complications.[2] Acute complications can include diabetic ketoacidosis, hyperosmolar hyperglycemic state, or death.[3] Serious long-term complications include cardiovascular disease, stroke, chronic kidney disease, foot ulcers, and damage to the eyes.[2]
The United Kingdom Prospective Diabetes Study (UKPDS) was a clinical study conducted by Z that was published in The Lancet in 1998. Around 3,800 people with type 2 diabetes were followed for an average of ten years, and were treated with tight glucose control or the standard of care, and again the treatment arm had far better outcomes. This confirmed the importance of tight glucose control, as well as blood pressure control, for people with this condition.[89][135][136]
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. 
Type 2 diabetes mellitus consists of an array of dysfunctions characterized by hyperglycemia and resulting from the combination of resistance to insulin action, inadequate insulin secretion, and excessive or inappropriate glucagon secretion. Poorly controlled type 2 diabetes is associated with an array of microvascular, macrovascular, and neuropathic complications.
Poor blood circulation and nerve damage. Damage to nerves and hardening of the arteries leads to decreased sensation and poor blood circulation in the feet. This can lead to increased infections and an increased risk of ulcers which heal poorly and can in turn significantly raises the risk of amputation. Damage to nerves may also lead to digestive problems, such as nausea, vomiting, and diarrhea.
Gestational diabetes can be a scary diagnosis, but like other forms of diabetes, it’s one that you can manage. It doesn’t mean that you had diabetes before you conceived or that you will have diabetes after you give birth. It means that, by working with your doctor, you can have a healthy pregnancy and a healthy baby. No matter what, know that you have all the support you need for both you and your baby to be at your best.
When glucose concentration in the blood remains high over time, the kidneys reach a threshold of reabsorption, and the body excretes glucose in the urine (glycosuria).[64] 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 is replaced osmotically from water in body cells and other body compartments, causing dehydration and increased thirst (polydipsia).[62] In addition, intracellular glucose deficiency stimulates appetite leading to excessive food intake (polyphagia).[65]
The United Kingdom Prospective Diabetes Study (UKPDS) was a clinical study conducted by Z that was published in The Lancet in 1998. Around 3,800 people with type 2 diabetes were followed for an average of ten years, and were treated with tight glucose control or the standard of care, and again the treatment arm had far better outcomes. This confirmed the importance of tight glucose control, as well as blood pressure control, for people with this condition.[89][135][136]

Type 2 diabetes primarily occurs as a result of obesity and lack of exercise.[1] Some people are more genetically at risk than others.[6] Type 2 diabetes makes up about 90% of cases of diabetes, with the other 10% due primarily to type 1 diabetes and gestational diabetes.[1] In type 1 diabetes there is a lower total level of insulin to control blood glucose, due to an autoimmune induced loss of insulin-producing beta cells in the pancreas.[12][13] Diagnosis of diabetes is by blood tests such as fasting plasma glucose, oral glucose tolerance test, or glycated hemoglobin (A1C).[3]
A study by Zheng et al indicated that HbA1c levels in persons with diabetes are longitudinally associated with long-term cognitive decline, as found using a mean 4.9 cognitive assessments of diabetes patients over a mean 8.1-year follow-up period. The investigators saw a significant link between each 1 mmol/mol rise in HbA1c and an increased rate of decline in z scores for global cognition, memory, and executive function. Patients in the study had a mean age of 65.6 years. The report cited a need for research into whether optimal glucose control in people with diabetes can affect their cognitive decline rate. [77, 78]
^ Rubino F, Nathan DM, Eckel RH, Schauer PR, Alberti KG, Zimmet PZ, Del Prato S, Ji L, Sadikot SM, Herman WH, Amiel SA, Kaplan LM, Taroncher-Oldenburg G, Cummings DE (June 2016). "Metabolic Surgery in the Treatment Algorithm for Type 2 Diabetes: A Joint Statement by International Diabetes Organizations". Diabetes Care. 39 (6): 861–77. doi:10.2337/dc16-0236. PMID 27222544.
In a 40-month study of 2977 middle-aged and older adults with long-standing type 2 diabetes, depression at baseline was associated with accelerated cognitive decline. [33, 34] The 531 subjects with scores of 10 or higher on the Patient Health Questionnaire Depression Scale at baseline had significantly lower scores on the Digit Symbol Substitution Test (DSST), the Rey Auditory Verbal Learning Test (RAVLT), and the modified Stroop test. Adjustment for other risk factors did not affect the association.
Diabetes is a disease that affects your body’s ability to produce or use insulin. Insulin is a hormone. When your body turns the food you eat into energy (also called sugar or glucose), insulin is released to help transport this energy to the cells. Insulin acts as a “key.” Its chemical message tells the cell to open and receive glucose. If you produce little or no insulin, or are insulin resistant, too much sugar remains in your blood. Blood glucose levels are higher than normal for individuals with diabetes. There are two main types of diabetes: Type 1 and Type 2.

The symptoms may relate to fluid loss and polyuria, but the course may also be insidious. Diabetic animals are more prone to infections. The long-term complications recognized in humans are much rarer in animals. The principles of treatment (weight loss, oral antidiabetics, subcutaneous insulin) and management of emergencies (e.g. ketoacidosis) are similar to those in humans.[126]

In the UKPDS, more than 5000 patients with type 2 diabetes were followed up for up to 15 years. Those in the intensely treated group had a significantly lower rate of progression of microvascular complications than did patients receiving standard care. Rates of macrovascular disease were not altered except in the metformin-monotherapy arm in obese individuals, in which the risk of myocardial infarction was significantly decreased.
Other potentially important mechanisms associated with type 2 diabetes and insulin resistance include: increased breakdown of lipids within fat cells, resistance to and lack of incretin, high glucagon levels in the blood, increased retention of salt and water by the kidneys, and inappropriate regulation of metabolism by the central nervous system.[10] However, not all people with insulin resistance develop diabetes, since an impairment of insulin secretion by pancreatic beta cells is also required.[13]

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.


A number of different healthcare professionals treat diabetes. A good first step is to talk to your primary care doctor about testing if you’re at risk for diabetes or if you begin experiencing symptoms associated with the disease. While you may work with your primary care doctor to manage your diabetes, it’s also possible to rely on another doctor or specialist to monitor your condition.
Diabetes is a chronic disease, for which there is no known cure except in very specific situations.[78] Management concentrates on keeping blood sugar levels as close to normal, without causing low blood sugar. This can usually be accomplished with a healthy diet, exercise, weight loss, and use of appropriate medications (insulin in the case of type 1 diabetes; oral medications, as well as possibly insulin, in type 2 diabetes).
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