Type 2 diabetes mellitus (T2DM) is a type of diabetes mellitus that is caused by insulin resistance combined with reduced insulin production.[1] It is often associated with certain lifestyle factors such as cigarette smoking, obesity, physical inactivity (lack of exercise) and poor diet and accounts for 85-95% of diabetes cases.[1] It is incurable, but usually manageable with medications and lifestyle changes.[1]

Signs and symptomsEdit

It is most commonly diagnosed in asymptomatic individuals. When it causes symptoms they can include the following:[2]

  • Polyuria
  • Polydypsia
  • Weight loss
  • Increased appetite
  • Feeling tired/fatigued
  • Slow-healing wounds
  • Infections including skin infections
  • Blurred vision
  • Mood swings

Possible complications, include (most of which usually only occur after having the disease for years or decades even):[3]

  • Strokes
  • Heart attacks
  • Several cancers, including: bladder, breast, colorectal, endometrial, kidney, liver and pancreatic cancers and non-Hodgkin's lymphoma.[4]
  • Peripheral vascular disease
  • Chronic kidney disease, that is, a kidney disease that has a slow and progressive course
  • Blindness and other vision problems
  • Neuropathy
  • Serious infections

These complications can be split up into three major categories: macrovascular, microvascular and nonvascular. Macrovascular refers to side effects that involve large blood vessels, they include heart attacks, peripheral vascular disease and strokes. Microvascular refers to side effects that involve small blood vessels, they include chronic kidney disease (nephropathy is the technical term), neuropathy and vision problems (or retinopathy). Nonvascular complications refer to complications that are unrelated to blood vessels, such as cancers and infections. 


Its exact cause is unknown, although both lifestyle and genetic factors appear to influence one's susceptibility to T2DM.[5] It is significantly more common in minority races (such as those of Australian Aboriginal, African, Hispanic, Maori and Pacific Islander ancestry).[5] It is often preceded by metabolic syndrome, risk factors include:

  • Age > 45 years
  • Obesity/overweight
  • Previous abnormal glucose-related blood test results
  • Hypertension
  • Dyslipidaemia (usually involving lower good cholesterol levels and higher amounts of triglycerides in the blood)
  • History of gestational diabetes mellitus, or of delivering a baby with a birth weight of over 9 pounds (~ 4.1 kg).


The major mainstay of T2DM treatment are lifestyle changes, especially dietary changes. Despite these measures most type 2 diabetics eventually require medications and in about 25% of cases insulin treatment is required.[2] Treatment is designed to do a number of things: firstly, to reduce risk factors for complications, including excess body fat (especially abdominal fat, that is, pot/beer-bellies), physical inactivitydietary factors (such as excess saturated fat, low levels of dietary fibre and excess processed sugars), hypercholesterolaemia, hyperglycaemia, hypertension, etc.[2]


Main page: Pharmacotherapy of type 2 diabetes mellitus.

The most common medications used to treat T2DM are oral antihyperglycaemics, that is agents that reduce blood sugar levels in people that are hyperglycaemic and are taken by mouth.[1] The usual medication that is trialled first when an antihyperglycaemic is required is metformin. This is likely due to two major factors, firstly it is the only antidiabetic that has been found, in well-designed clinical trials, to reduce the risk of heart attacks, strokes, cancer and death from any cause in type 2 diabetics and secondly its side effects are usually the least worrisome or problematic. It works by improving insulin sensitivity, reducing hepatic gluconeogenesis and increasing the utilization of glucose in the periphery, especially in skeletal muscles (that is those muscles that are bound to bones, such as those that are enable one to type on a keyboard, and are voluntarily controlled, that is you can consciously control them).[6] Its most common side effects are digestive in nature and include: nausea, vomiting, weight loss, appetite loss, diarrhoea and malabsorption of vitamin B12.[7]

If a trial of metformin fails or if the affected person has some condition or is on a medication that excludes them from taking metformin then a sulfonylurea might be used.[8]:9-10 They work by increasing insulin secretion by the β cells of the pancreas whilst simultaneously reducing insulin resistance.[9] The most common side effects associated with sulfonylureas are likely due to its effects on insulin secretion and include weight gain and hypoglycaemia.[9] In contrast to metformin sulfonylureas may be associated with an increased risk of all-cause and macrovascular-related mortality.[10]

If these are unsuccessful the following agents may be tried (with or without a sulfonylurea or metformin): α-glucoside inhibitors (AGIs), amylinomimetics (AMs), bile acid sequestrants (BASs), dipeptidyl peptidase 4 (DPP-4) inhibitors (DPIs), dopamine agonists (DAs), glucagon-like peptide-1 (GLP-1) agonists (GLPAs), insulins, meglitinides, selective sodium-glucose transporter-2 inhibitors (SGTIs) and thiazolidinediones (TZDs).[11]


Overall diabetics are twice as likely as their peers to die in any given time period, overall this equates to life expectancy reduction of 7 years;[2] and is a risk factor for various different serious conditions, see the signs and symptoms section for details.


Diabetes mellitus is the eighth leading cause of death, worldwide, at 1.3 million deaths annually.[12] Around 370 million people, worldwide, are believed to have T2DM.[1]

See alsoEdit

External linksEdit

Further readingEdit

For consumers

Reference listEdit

  1. 1.0 1.1 1.2 1.3 1.4 Kahn, SE; Cooper, ME; Del Prato, S (March 2014). "Pathophysiology and treatment of type 2 diabetes: perspectives on the past, present, and future.". Lancet 383 (9922): 1068–83. PMID 24315620. doi:10.1016/S0140-6736(13)62154-6. 
  2. 2.0 2.1 2.2 2.3 National Collaborating Centre for Chronic Conditions (2008). Type 2 Diabetes National Clinical Guideline for Management in Primary and Secondary Care (Update). London, UK: Royal College of Physicians of London. ISBN 978-1-86016-333-3. PMID 21678628.  Unknown parameter |nice= ignored (help); Unknown parameter |nbk= ignored (help)
  3. "Diabetes". World Health Organization. Geneva, Switzerland: World Health Organization. October 2013. 
  4. Xu, CX; Zhu, HH; Zhu, YM (June 2014). "Diabetes and cancer: Associations, mechanisms, and implications for medical practice.". World Journal of Diabetes 5 (3): 372–80. PMC 4058741. PMID 24936258. doi:10.4239/wjd.v5.i3.372. 
  5. 5.0 5.1 Griffing, GT, ed. (16 September 2014). "Type 2 Diabetes Mellitus". Medscape Reference. WebMD. Retrieved 25 September 2014. 
  6. Correia, S; Carvalho, C; Santos, MS; Seiça, R; Oliveira, CR; Moreira, PI (November 2008). "Mechanisms of action of metformin in type 2 diabetes and associated complications: an overview." (PDF). Mini Reviews in Medicinal Chemistry 8 (13): 1343–54. PMID 18991752. doi:10.2174/138955708786369546. 
  7. Rossi, S, ed. (July 2014). "Metformin". Australian Medicines Handbook. Adelaide, Australia: Australian Medicines Handbook Pty Ltd. Retrieved 27 September 2014. 
  8. World Health Organization (2012). Prevention and Control of Noncommunicable Diseases: Guidelines for primary health care in low resource settings. Geneva, Switzerland: World Health Organization. ISBN 978-92-4-154839-7. PMID 23844451.  Unknown parameter |nbk= ignored (help)
  9. 9.0 9.1 Rossi, S, ed. (July 2014). "Sulfonylureas". Australian Medicines Handbook. Adelaide, Australia: Australian Medicines Handbook Pty Ltd. Retrieved 27 September 2014. 
  10. Phung, OJ; Schwartzman, E; Allen, RW; Engel, SS; Rajpathak, SN (October 2013). "Sulphonylureas and risk of cardiovascular disease: systematic review and meta-analysis.". Diabetic Medicine 30 (10): 1160–71. PMID 23663156. doi:10.1111/dme.12232. 
  11. Second- and Third-Line Pharmacotherapy for Type 2 Diabetes: Update [Internet]. Ottawa, Canada: Canadian Agency for Drugs and Technologies in Health. July 2013. PMID 24278998.  Unknown parameter |nbk= ignored (help)
  12. "The top 10 causes of death". World Health Organization. Geneva, Switzerland: World Health Organization. May 2014. 

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