Diabetes is suspected based on symptoms. Urine tests and blood tests can be used to confirm a diagnose of diabetes based on the amount of glucose found. Urine can also detect ketones and protein in the urine that may help diagnose diabetes and assess how well the kidneys are functioning. These tests also can be used to monitor the disease once the patient is on a standardized diet, oral medications, or insulin.
The American Diabetes Association sponsored an international panel in 1995 to review the literature and recommend updates of the classification of diabetes mellitus. The definitions and descriptions that follow are drawn from the Report of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus. The report was first approved in 1997 and modified in 1999. Although other terms are found in older literature and remain in use, their use in current clinical practice is inappropriate. Epidemiologic and research studies are facilitated by use of a common language.
Jump up ^ Feinman, RD; Pogozelski, WK; Astrup, A; Bernstein, RK; Fine, EJ; Westman, EC; Accurso, A; Frassetto, L; Gower, BA; McFarlane, SI; Nielsen, JV; Krarup, T; Saslow, L; Roth, KS; Vernon, MC; Volek, JS; Wilshire, GB; Dahlqvist, A; Sundberg, R; Childers, A; Morrison, K; Manninen, AH; Dashti, HM; Wood, RJ; Wortman, J; Worm, N (January 2015). "Dietary carbohydrate restriction as the first approach in diabetes management: critical review and evidence base". Nutrition. Burbank, Los Angeles County, Calif. 31 (1): 1–13. doi:10.1016/j.nut.2014.06.011. PMID 25287761.
Diabetes mellitus (DM) is a strong predictor of cardiovascular morbidity and mortality and is associated with both micro- and macrovascular complications.1 Cardiovascular disease (CVD) causes up to 70% of all deaths in people with DM. The epidemic of DM will thus be followed by a burden of diabetes-related vascular diseases. The number of DM patients increases with aging of the population, in part because of the increasing prevalence of obesity and sedentary lifestyle. Although the mortality from coronary artery disease (CAD) in patients without DM has declined since the 1990s, the mortality in men with type 2 diabetes (T2DM) has not changed significantly.2 Moreover, DM is an independent risk factor for heart failure. Heart failure is closely related to diabetic cardiomyopathy: changes in the structure and function of the myocardium are not directly linked to CAD or hypertension. Diabetic cardiomyopathy is clinically characterized by an initial increase in left ventricular stiffness and subclinical diastolic dysfunction, gradually compromising left ventricular systolic function with loss of contractile function and progress into overt congestive heart failure. DM accounts for a significant percentage of patients with a diagnosis of heart failure in epidemiologic studies such as the Framingham Study and the UK Prospective Diabetes Study (UKPDS).2 A 1% increase in glycated hemoglobin (HbA1c) correlates to an increment of 8% in heart failure.3 The prevalence of heart failure in elderly diabetic patients is up to 30%.3
Feeling famished all the time? Your body could be trying to tell you that something’s up with your blood sugar. Many people with diabetes experience extreme hunger when their condition is unmanaged, thanks to high blood sugar levels. When your body can’t effectively convert the sugar in your blood into usable energy, this may leave you pining for every sandwich or sweet you see. And if you’re looking for a filling snack that won’t put your health at risk, enjoy one of the 25 Best and Worst Low-Sugar Protein Bars!
Most cases of diabetes involve many genes, with each being a small contributor to an increased probability of becoming a type 2 diabetic. 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%. As of 2011, more than 36 genes had been found that contribute to the risk of type 2 diabetes. All of these genes together still only account for 10% of the total heritable component of the disease. 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. Most of the genes linked to diabetes are involved in beta cell functions.
Exposure to certain viral infections (mumps and Coxsackie viruses) or other environmental toxins may serve to trigger abnormal antibody responses that cause damage to the pancreas cells where insulin is made. Some of the antibodies seen in type 1 diabetes include anti-islet cell antibodies, anti-insulin antibodies and anti-glutamic decarboxylase antibodies. These antibodies can be detected in the majority of patients, and may help determine which individuals are at risk for developing type 1 diabetes.
Taking the drugs used to treat diabetes, particularly insulin, may be difficult for some older people. For those with vision problems or other problems that make accurately filling a syringe difficult, a caregiver can prepare the syringes ahead of time and store them in the refrigerator. People whose insulin dose is stable may purchase pre-filled syringes. Prefilled insulin pen devices may be easier for people with physical limitations. Some of these devices have large numbers and easy-to-turn dials.
Type 2 diabetes is mainly caused by insulin resistance. This means no matter how much or how little insulin is made, the body can't use it as well as it should. As a result, glucose can't be moved from the blood into cells. Over time, the excess sugar in the blood gradually poisons the pancreas causing it to make less insulin and making it even more difficult to keep blood glucose under control.
The problem with sugar, regardless of type, is the sheer amount of it that’s found in the Standard American Diet (SAD), which is the typical eating plan many people in the United States — as well as those in an increasing number of modernized countries — have developed a taste for. When consumed in excess, foods in this category can lead to heart disease, stroke, and other serious health issues. “Often, foods with added sugar also contain fat,” explains Grieger, noting that these components go hand in hand when it comes to the risk for insulin resistance, the hallmark of type 2 diabetes.
Although some people with this type of diabetes are thin, the majority of people (90%) are overweight. Losing weight, even 2 kg to 5 kg (5 lbs to 10 lbs) can help lower blood glucose levels. For many people, following a healthy diet and an exercise program may be all that is needed to help control glucose levels. For others, healthy eating and exercise alone aren't enough to lower blood glucose levels.
Large, population-based studies in China, Finland and USA have recently demonstrated the feasibility of preventing, or delaying, the onset of diabetes in overweight subjects with mild glucose intolerance (IGT). The studies suggest that even moderate reduction in weight and only half an hour of walking each day reduced the incidence of diabetes by more than one half.
Recently, battery-operated insulin pumps have been developed that can be programmed to mimic normal insulin secretion more closely. A person wearing an insulin pump still must monitor blood sugar several times a day and adjust the dosage, and not all diabetic patients are motivated or suited to such vigilance. It is hoped that in the future an implantable or external pump system may be perfected, containing a glucose sensor. In response to data from the sensor the pump will automatically deliver insulin according to changing levels of blood glucose.
Persons with diabetes who take insulin must be careful about indulging in unplanned exercise. Strenuous physical activity can rapidly lower their blood sugar and precipitate a hypoglycemic reaction. For a person whose blood glucose level is over 250 mg/dl, the advice would be not to exercise at all. At this range, the levels of insulin are too low and the body would have difficulty transporting glucose into exercising muscles. The result of exercise would be a rise in blood glucose levels.
Type 2 diabetes can be prevented with lifestyle changes. People who are overweight and lose as little as 7 percent of their body weight and who increase physical activity (for example, walking 30 minutes per day) can decrease their risk of diabetes mellitus by more than 50%. Metformin and acarbose, drugs that are used to treat diabetes, may reduce the risk of diabetes in people with impaired glucose regulation.
Some patients with type 2 DM can control their disease with a calorically restricted diet (for instance 1600 to 1800 cal/day), regular aerobic exercise, and weight loss. Most patients, however, require the addition of some form of oral hypoglycemic drug or insulin. Oral agents to control DM include sulfonylurea drugs (such as glipizide), which increase pancreatic secretion of insulin; biguanides or thiazolidinediones (such as metformin or pioglitazone), which increase cellular sensitivity to insulin; or a-glucosidase inhibitors (such as acarbose), which decrease the absorption of carbohydrates from the gastrointestinal tract. Both types of diabetics also may be prescribed pramlintide (Symlin), a synthetic analog of human amylin, a hormone manufactured in the pancreatic beta cells. It enhances postprandial glucose control by slowing gastric emptying, decreasing postprandial glucagon concentrations, and regulating appetite and food intake; thus pramlintide is helpful for patients who do not achieve optimal glucose control with insulin and/or oral antidiabetic agents. When combinations of these agents fail to normalize blood glucose levels, insulin injections are added. Tight glucose control can reduce the patient’s risk of many of the complications of the disease. See: illustration
Risk factors for type 2 diabetes include obesity, high cholesterol, high blood pressure, and physical inactivity. The risk of developing type 2 diabetes also increases as people grow older. People who are over 40 and overweight are more likely to develop type 2 diabetes, although the incidence of this type of diabetes in adolescents is growing. Diabetes is more common among Native Americans, African Americans, Hispanic Americans and Asian Americans/Pacific Islanders. Also, people who develop diabetes while pregnant (a condition called gestational diabetes) are more likely to develop type 2 diabetes later in life.
Type 1 diabetes mellitus is predominantly a disease of the young, usually developing before 20 years of age. Overall, type I DM makes up approximately 15% of all cases of diabetes. It develops in approximately 1 in 600 children and is one of the most common chronic diseases in children. The incidence is relatively low for children under the age of 5, increases between 5 and 15, and then tapers off.
In an otherwise healthy individual, blood glucose levels usually do not rise above 180 mg/dL (9 mmol/L). In a child with diabetes, blood sugar levels rise if insulin is insufficient for a given glucose load. The renal threshold for glucose reabsorption is exceeded when blood glucose levels exceed 180 mg/dL (10 mmol/L), causing glycosuria with the typical symptoms of polyuria and polydipsia. (See Pathophysiology, Clinical, and Treatment.)
Jump up ^ Haw JS, Galaviz KI, Straus AN, Kowalski AJ, Magee MJ, Weber MB, Wei J, Narayan KM, Ali MK (December 2017). "Long-term Sustainability of Diabetes Prevention Approaches: A Systematic Review and Meta-analysis of Randomized Clinical Trials". JAMA Internal Medicine. 177 (12): 1808–1817. doi:10.1001/jamainternmed.2017.6040. PMC 5820728. PMID 29114778.
Jump up ^ Kyu, Hmwe H.; Bachman, Victoria F.; Alexander, Lily T.; Mumford, John Everett; Afshin, Ashkan; Estep, Kara; Veerman, J. Lennert; Delwiche, Kristen; Iannarone, Marissa L.; Moyer, Madeline L.; Cercy, Kelly; Vos, Theo; Murray, Christopher J.L.; Forouzanfar, Mohammad H. (9 August 2016). "Physical activity and risk of breast cancer, colon cancer, diabetes, ischemic heart disease, and ischemic stroke events: systematic review and dose-response meta-analysis for the Global Burden of Disease Study 2013". The BMJ. 354: i3857. doi:10.1136/bmj.i3857. PMC 4979358. PMID 27510511.
The information contained in this monograph is for educational purposes only. This information is not a substitute for professional medical advice, diagnosis, or treatment. If you have or suspect you may have a health concern, consult your professional health care provider. Reliance on any information provided in this monograph is solely at your own risk.
If the amount of insulin available is insufficient, or if cells respond poorly to the effects of insulin (insulin insensitivity or insulin resistance), or if the insulin itself is defective, then glucose will not be absorbed properly by the body cells that require it, and it will not be stored appropriately in the liver and muscles. The net effect is persistently high levels of blood glucose, poor protein synthesis, and other metabolic derangements, such as acidosis.
Cataracts and glaucoma are also more common among diabetics. It is also important to note that since the lens of the eye lets water through, if blood sugar concentrations vary a lot, the lens of the eye will shrink and swell with fluid accordingly. As a result, blurry vision is very common in poorly controlled diabetes. Patients are usually discouraged from getting a new eyeglass prescription until their blood sugar is controlled. This allows for a more accurate assessment of what kind of glasses prescription is required.
^ Jump up to: a b Petzold A, Solimena M, Knoch KP (October 2015). "Mechanisms of Beta Cell Dysfunction Associated With Viral Infection". Current Diabetes Reports (Review). 15 (10): 73. doi:10.1007/s11892-015-0654-x. PMC 4539350. PMID 26280364. So far, none of the hypotheses accounting for virus-induced beta cell autoimmunity has been supported by stringent evidence in humans, and the involvement of several mechanisms rather than just one is also plausible.
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.
To measure blood glucose levels, a blood sample is usually taken after people have fasted overnight. However, it is possible to take blood samples after people have eaten. Some elevation of blood glucose levels after eating is normal, but even after a meal the levels should not be very high. Fasting blood glucose levels should never be higher than 125 mg/dL. Even after eating, blood glucose levels should not be higher than 199 mg/dL.
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.
Then, once you do have an injury, uncontrolled diabetes can make it harder for your body to heal. “High blood sugars provide a good environment for bacteria to grow,” she says. That's because diabetes is also often accompanied by high blood pressure and high cholesterol, and the resulting plaque buildup can narrow blood vessels, reducing blood supply and leading to slow healing.