Type 2 Diabetes
(Non-insulin Dependent Diabetes Mellitus, Adult-onset Diabetes Mellitus)
Definition
Type 2 diabetes is a disorder in which the body is resistant to high levels of insulin. Insulin is a hormone produced by the pancreas that helps the body convert food into energy. Without insulin, glucose (sugar) from the food you eat cannot enter cells. This causes glucose to build up in the blood. Meanwhile, your body tissues are starved for energy. However, in type 2 diabetes, there is plenty of insulin but the cells are resistant to its action.
Long-term, high blood sugar levels can damage the kidneys, eyes, nerves, and other tissues.
The Pancreas © 2008 Nucleus Medical Art, Inc.
Causes
Two conditions contribute to type 2 diabetes:
- Insulin resistance related to excess body fat (In this case, the body is unable to effectively use the insulin it produces.)
- Failure of the body to make an adequate amount of insulin
Risk Factors
A risk factor is something that increases your chance of getting a disease or condition.
- Age: 40 or older
- Sex: more common in older women than men
- Obesity or being overweight (especially excess weight in the upper body and abdomen)
- Lack of physical activity
- Family members with type 2 diabetes
- History of gestational diabetes
- History of impaired glucose tolerance
- Race: African American, Hispanic, Native American, Asian American, or Pacific Islander
- Endocrine disorders (Cushing’s syndrome, hyperthyroidism, acromegaly, polycystic ovary syndrome, pheochromocytoma, glucagonoma)
- Medications (pentamidine, nicotinic acid, glucocorticoids, thiazide)
- Genetic factors
Symptoms
Type 2 diabetes may not produce symptoms for years.
Symptoms in type 2 diabetes may be due to either high blood sugar or diabetic complications. These symptoms may include the following:
Diagnosis
The doctor will ask about your symptoms and medical and family history, and perform a physical exam.
Diagnosis is based on the results of blood tests and other criteria, including:
- Symptoms of diabetes and a random blood test revealing a blood sugar level greater than or equal to 200 milligrams per deciliter of blood (mg/dL) [11.1 millimole per liter (mmol/L)]
- Blood sugar tests after you have not eaten for eight or more hours revealing blood sugar levels greater than or equal to 126 mg/dL (7.0 mmol/L) on two different days
- A glucose tolerance test measuring blood sugar two hours after you consume glucose with a measurement greater than or equal to 200 mg/dL (11.1 mmol/L)
Researchers found that group education may help people recently diagnosed with type 2 diabetes reach their goals in losing weight and quitting smoking, but not in controlling their blood sugar levels. * 8
Treatment
Diabetes treatment aims to maintain blood sugar at levels as close to normal as possible. Regular medical care is essential for preventing or delaying complications.
In a study, patients who received brief counseling during their regular doctor's appointments reported an increase in physical activity, but no difference in weight loss. * 9
Diet
- Follow a balanced meal plan, eating consistent and moderate amounts of food at regular times.
- Do not skip meals.
- Eat plenty of fruits, vegetables, and fiber.
- Eat limited amounts of fat.
- Eat moderate amounts of protein and low-fat dairy products.
- Carefully limit foods containing sugar, which may be included as part of a balanced diet plan.
- Eat a bedtime snack with protein and a starchy food.
- Keep a record of your food intake to help a dietitian or doctor advise you based on your nutritional needs.
Weight Loss
If you are overweight, talk to your doctor about a reasonable weight goal and a safe diet program.
Exercise
Physical activity helps the body use blood sugar. It will also help you reach and maintain a healthy weight, and lower the levels of fat in your blood. Follow your doctor's recommendations for activity levels and restrictions. In a recent review, exercise was found to improve blood sugar control in patients with type 2 diabetes. * 2
Oral Medication
Medications taken by mouth may be used to lower blood sugar. These may include:
- Drugs that prompt the beta cells in the pancreas to make more insulin (eg, sulfonylureas [glyburide, tolazamide])
- Insulin sensitizers—a class of drugs that help the body better use insulin (eg, rosiglitazone and pioglitazone)
- Starch blockers—a class of drugs (eg, acarbose and miglitol) that helps decrease the absorption of glucose into the bloodstream (through the intestine), resulting in better blood sugar control (a blunted increase) after a meal
- Drugs that help reduce the production of glucose by the liver (eg, metformin)
- Amylin analogues (eg, pramlintide)
- Dipeptidyl peptidase IV (DDPP-4) inhibitor (eg, sitagliptin)
- Incretin-mimetic (eg, exenatide)
Two studies show the potential of increased harm when using the medications rosiglitazone or gliclazide to reach intensive blood sugar goals (hemoglobin A1C < 6.5%).*3,6,7,10
Insulin
Insulin by injection supplement the insulin produced by the body. Insulin therapy is needed when blood sugar levels are not kept low enough with diet, exercise, and oral medications, usually in advanced cases.
Blood Sugar Testing
Checking blood sugar levels during the day (fasting and 2 hours after meals) helps you and your doctor track the amount of glucose in your blood and determine if the dose or the type of antidiabetic treatment needs to be adjusted. Testing is easy with a blood glucose monitor. Keeping track of blood glucose levels is particularly important if you take insulin.
However, many patients with type 2 diabetes can be adequately managed by using another test called glycosylated hemoglobin or hemoglobin A1c (HbA1c), which is performed in a doctor’s office. Unlike blood sugar levels, HbA1c has the advantage of measuring average blood glucose levels over the previous three-month period, which marks the effectiveness of diabetes management over the long-term. Most diabetics are recommended to keep their HbA1c levels below 7%.
A study suggests that regular blood sugar testing may not be necessary in patients with type 2 diabetes whose condition is under reasonably good control without insulin. * 4 However, talk with your doctor before stopping blood sugar monitoring.
Alternative Therapies
Researchers studies vitamin E supplementation in a particular group of patients—those with type 2 diabetes mellitus and a certain genotype (called Haptoglobin 2-2). Vitamin E was associated with a decrease in the rates of cardiovascular events. * 5
Prevention
Regular physical activity and maintaining a healthy weight can reduce your chance of developing type 2 diabetes. In a trial of patients who were overweight and had prediabetes, lifestyle changes reduced the incidence of diabetes for up to seven years. * 1
Although lifestyle changes appear to be more effective than medications in individuals with glucose intolerance, ask your doctor if taking a drug, such as metformin or rosiglitazone, may help reduce your risk of developing type 2 diabetes.
RESOURCES:
American Diabetes Association
http://www.diabetes.org
National Diabetes Information Clearinghouse
http://diabetes.niddk.nih.gov
CANADIAN RESOURCES:
Canadian Diabetes Association
http://www.diabetes.ca
Team Diabetes Canada
Canadian Diabetes Association
http://www.diabetes.ca/section_donations/TeamDiabetesIndex.asp
References:
American Association of Clinical Endocrinologists, American College of Endocrinology. Medical guidelines for the management of diabetes mellitus. The AACe system of intensive diabetes self-management. 2002 update. Endocrine Practice. 2002;8(suppl 1):S40-82.
American Diabetes Association website. Available at: http://www.diabetes.org .
Boren SA, Gunlock TL, Schaefer J, Albright A. Reducing risks in diabetes self-management: a systematic review of the literature. Diabetes Educ. 2007;33:1053-1077.
The Diabetes Monitor. Information about Acarbose (Precose). Available at: http://www.diabetesmonitor.com/acarbose.htm . Accessed on May 26, 2006.
Diagnosis and classification of diabetes mellitus. Diabetes Care. 2005;28(suppl 1):S37-42.
Gaede P, Vedel P, Larsen N, et al. Multifactorial intervention and cardiovascular disease in patients with type 2 diabetes. N Engl J Med. 2003; 248:383-393.
Harsch IA. Inhaled insulins: their potential in the treatment of diabetes mellitus. Treat Endocrinol. 2005;4:131-138.
Marre M. Reducing cardiovascular risk in diabetes. J Hypertens. 2007;(supp 11)S19-22.
National Center for Chronic Disease Prevention and Health Promotion. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/nccdphp/ .
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) website. Available at: http://www.niddk.nih.gov/ .
Physical activity/exercise and diabetes. Diabetes Care. 2004;27(suppl 1):S58-62.
Screening for type 2 diabetes. Diabetes Care. 2004;27(suppl 1):S11-4.
UK Prospective Diabetes Study Group. Effect of intensive blood-glucose control with metformin on complications in overweight patients with type 2 diabetes. Lancet. 1998; 352:954-965.
US Preventive Services Task Force (USPSTF). Screening for type 2 diabetes mellitus in adults: recommendations and rationale. Ann Intern Med. 2003; 138:212-214.
* 1 11/29/06 DynaMed Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance : Lindstrom J, Ilanne-Parikka P, Peltonen M, Aunola S, Eriksson JG, Hemio K, et al. Sustained reduction in the incidence of type 2 diabetes by lifestyle intervention: follow-up of the Finnish Diabetes Prevention Study. Lancet. 2006;368:1673-1679.
* 2 9/19/06 DynaMed Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance : Thomas DE, Elliott EJ, Naughton GA. Exercise for type 2 diabetes mellitus. Cochrane Database of Systematic Reviews. 2006; No.: CD002968. DOI: 10.1002/14651858.CD002968.pub2.
* 3 6/1/2007 DynaMed Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance : Nissen SE, Wolski K. Effect of rosiglitazone on the risk of myocardial infarction and death from cardiovascular causes. N Engl J Med. 2007 May 21. [Epub ahead of print]
* 4 7/13/2007 DynaMed Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance : Farmer A, Wade A, Goyder E, et al. Impact of self monitoring of blood glucose in the management of patients with non-insulin treated diabetes: open parallel group randomised trial. BMJ. 2007 Jun 25. [Epub ahead of print]
* 5 12/13/2007 DynaMed Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance : Milman U, Blum S, Shapira C, et al. Vitamin E supplementation reduces cardiovascular events in a subgroup of middle-aged individuals with both type 2 diabetes mellitus and the haptoglobin 2-2 genotype. A prospective double-blinded clinical trial. Arterioscler Thromb Vasc Biol. 2007 Nov 21. [Epub ahead of print]
* 6 2/13/2008 DynaMed Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance : For safety, NHLBI changes intensive blood sugar treatment strategy in clinical trial of diabetes and cardiovascular disease. NIH News. National Institutes of Health website. Available at: http://www.nih.gov/news/health/feb2008/nhlbi-06.htm . Accessed February 13, 2008.
* 7 2/21/2008 DynaMed Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance : Major international diabetes study does not confirm increased risk of death reported by US trial. Action in Diabetes and Vascular Disease: PreteraAx and DiamicroN MR Controlled Evaluation (ADVANCE) website. Available at: http://www.advance-trial.com/static/html/virtual/contents.asp?P=39 . Accessed February 21, 2008.
* 8 2/28/2008 DynaMed Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance : Davies MJ, Heller S, Skinner TC, et al. Effectiveness of the diabetes education and self management for ongoing and newly diagnosed (DESMOND) programme for people with newly diagnosed type 2 diabetes: cluster randomised controlled trial. BMJ. 2008 Feb 14. [Epub ahead of print]
* 9 2/28/2008 DynaMed Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance : Christian JG, Bessesen DH, Byers TE, Christian KK, Goldstein MG, Bock BC. Clinic-based support to help overweight patients with type 2 diabetes increase physical activity and lose weight. Arch Intern Med. 2008;168:141-146.
* 10 6/18/2008 DynaMed Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance: ADVANCE Collaborative Group. Intensive blood glucose control and vascular outcomes in patients with type 2 diabetes. N Engl J Med. 2008;358:2560-2572. Epub 2008 Jun 6.
Last reviewed March 2008 by David Juan, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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