The amount of glucose in your bloodstream is tightly regulated by the hormone insulin. Insulin is always being released in small amounts by the pancreas. When the amount of glucose in your blood rises to a certain level, the pancreas will release more insulin to push more glucose into the cells. This causes the glucose levels in your blood (blood glucose levels) to drop.

People may see a primary care doctor or a family practitioner when they get sick or when having general checkups. A specialist called an endocrinologist has special training in diagnosing and treating diabetes. However, if you cannot find an endocrinologist in your area, you can alternatively look for a primary care doctor, who can either be an internist or a family practitioner. 
These benefits are weighed against the risk of hypoglycemia and the short-term costs of providing high-quality preventive care. Studies have shown cost savings due to a reduction in acute diabetes-related complications within 1-3 years after starting effective preventive care. Some studies suggest that broad-based focus on treatment (eg, glycemia, nutrition, exercise, lipids, hypertension, smoking cessation) is much more likely to reduce the burden of excess microvascular and macrovascular events.
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.
The relationship between type 2 diabetes and the main modifiable risk factors (excess weight, unhealthy diet, physical inactivity and tobacco use) is similar in all regions of the world. There is growing evidence that the underlying determinants of diabetes are a reflection of the major forces driving social, economic and cultural change: globalization, urbanization, population aging, and the general health policy environment.[77]
Another diabetes-related sexual dysfunction symptom in men is reduced amounts of ejaculation, or retrograde ejaculation. Retrograde ejaculation is a condition in which the semen goes into the bladder, rather than out of the body through the urethra. Diabetes and damage to the blood vessels causes nerve damage to the muscles that control the bladder and urethra, which results in this problem.
^ 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.
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] 

Differences between the patient populations in these studies and the UKPDS may account for some of the differences in outcome. The patients in these 3 studies had established diabetes and had a prior cardiovascular disease event or were at high risk for a cardiovascular disease event, whereas patients in the UKPDS study were younger, with new-onset diabetes and low rates of cardiovascular disease.
^ 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.

Also called diabe·tes mel·li·tus [mel-i-tuh s, muh-lahy-] . a disorder of carbohydrate metabolism, usually occurring in genetically predisposed individuals, characterized by inadequate production or utilization of insulin and resulting in excessive amounts of glucose in the blood and urine, excessive thirst, weight loss, and in some cases progressive destruction of small blood vessels leading to such complications as infections and gangrene of the limbs or blindness.
Type 1 diabetes is partly inherited, with multiple genes, including certain HLA genotypes, known to influence the risk of diabetes. In genetically susceptible people, the onset of diabetes can be triggered by one or more environmental factors,[42] such as a viral infection or diet. Several viruses have been implicated, but to date there is no stringent evidence to support this hypothesis in humans.[42][43] Among dietary factors, data suggest that gliadin (a protein present in gluten) may play a role in the development of type 1 diabetes, but the mechanism is not fully understood.[44][45]
^ McBrien K, Rabi DM, Campbell N, Barnieh L, Clement F, Hemmelgarn BR, Tonelli M, Leiter LA, Klarenbach SW, Manns BJ (September 2012). "Intensive and Standard Blood Pressure Targets in Patients With Type 2 Diabetes Mellitus: Systematic Review and Meta-analysis". Archives of Internal Medicine. 172 (17): 1296–303. doi:10.1001/archinternmed.2012.3147. PMID 22868819.
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 type 1 diabetes 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.[89][133][134]
For type 2 diabetes mellitus to occur, both insulin resistance and inadequate insulin secretion must exist. For example, all overweight individuals have insulin resistance, but diabetes develops only in those who cannot increase insulin secretion sufficiently to compensate for their insulin resistance. Their insulin concentrations may be high, yet inappropriately low for the level of glycemia.
Despite advanced age, multiparity, obesity, and social disadvantage, patients with type 2 diabetes were found to have better glycemic control, fewer large-for-gestational-age infants, fewer preterm deliveries, and fewer neonatal care admissions compared with patients with type 1 diabetes. This suggests that better tools are needed to improve glycemic control in patients with type 1 diabetes. [95] (For more information, see Diabetes Mellitus and Pregnancy.)
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. 

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]
As of 2017, an estimated 425 million people had diabetes worldwide,[9] with type 2 diabetes making up about 90% of the cases.[17][18] This represents 8.8% of the adult population,[9] with equal rates in both women and men.[19] Trend suggests that rates will continue to rise.[9] Diabetes at least doubles a person's risk of early death.[2] In 2017, diabetes resulted in approximately 3.2 to 5.0 million deaths.[9] The global economic cost of diabetes related health expenditure in 2017 was estimated at US$727 billion.[9] In the United States, diabetes cost nearly US$245 billion in 2012.[20] Average medical expenditures among people with diabetes are about 2.3 times higher.[21]
Culturally appropriate education may help people with type 2 diabetes control their blood sugar levels, for up to 24 months.[93] If changes in lifestyle in those with mild diabetes has not resulted in improved blood sugars within six weeks, medications should then be considered.[23] There is not enough evidence to determine if lifestyle interventions affect mortality in those who already have DM2.[64]

The term "diabetes" or "to pass through" was first used in 230 BCE by the Greek Apollonius of Memphis.[111] The disease was considered rare during the time of the Roman empire, with Galen commenting he had only seen two cases during his career.[111] 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).[113]