Diabetes is a chronic disease that occurs either when the pancreas does not produce enough insulin or when the body cannot effectively use the insulin it produces. Insulin is a hormone that regulates blood glucose. Hyperglycaemia, also called raised blood glucose or raised blood sugar, is a common effect of uncontrolled diabetes and over time leads to serious damage to many of the body’s systems, especially the nerves and blood vessels.
Type 1 diabetes
Type 1 diabetes (previously known as insulin-dependent, juvenile or childhood-onset) is characterised by deficient insulin production and requires daily administration of insulin. In 2017 there were 9 million people with type 1 diabetes; the majority of them live in high-income countries. Neither its cause nor the means to prevent it are known.
Symptoms include excessive excretion of urine (polyuria), thirst (polydipsia), constant hunger, weight loss, vision changes, and fatigue. These symptoms may occur suddenly.
Type 2 diabetes
Type 2 diabetes (formerly called non-insulin-dependent, or adult-onset) results from the body’s ineffective use of insulin. More than 95% of people with diabetes have type 2 diabetes. This type of diabetes is largely the result of excess body weight and physical inactivity.
Symptoms may be similar to those of type 1 diabetes but are often less marked. As a result, the disease may be diagnosed several years after onset, after complications have already arisen.
Until recently, this type of diabetes was seen only in adults but it is now also occurring increasingly frequently in children.
Gestational diabetes
Gestational diabetes is hyperglycemia with blood glucose values above normal but below those diagnostic of diabetes. Gestational diabetes occurs during pregnancy
Women with gestational diabetes are at an increased risk of complications during pregnancy and at delivery. These women and possibly their children are also at increased risk of type 2 diabetes in the future.
Gestational diabetes is diagnosed through prenatal screening, rather than through reported symptoms.
Health impact
Over time, diabetes can damage the heart, blood vessels, eyes, kidneys, and nerves.
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Adults with diabetes have a two- to three-fold increased risk of heart attacks and strokes.
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Combined with reduced blood flow, neuropathy (nerve damage) in the feet increases the chance of foot ulcers, infection and eventual need for limb amputation.
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Diabetic retinopathy is an important cause of blindness and occurs as a result of long-term accumulated damage to the small blood vessels in the retina. Close to 1 million people are blind due to diabetes.
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Diabetes is among the leading causes of kidney failure.
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People with diabetes are more likely to have poor outcomes for several infectious diseases, including COVID-19.
Prevention
Lifestyle measures have been shown to be effective in preventing or delaying the onset of type 2 diabetes. To help prevent type 2 diabetes and its complications, people should:
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achieve and maintain a healthy body weight.
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be physically active – doing at least 30 minutes of regular, moderate-intensity activity on most days. More activity is required for weight control;
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eat a healthy diet, avoiding sugar and saturated fats.
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Avoid tobacco use – smoking increases the risk of diabetes and cardiovascular disease.
Diagnosis and treatment
Early diagnosis can be accomplished through relatively inexpensive testing of blood glucose.
Treatment of diabetes involves diet and physical activity along with lowering of blood glucose and the levels of other known risk factors that damage blood vessels. Tobacco use cessation is also important to avoid complications.
Interventions that are both cost-saving and feasible in low- and middle-income countries include:
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blood glucose control, particularly in type 1 diabetes. People with type 1 diabetes require insulin, people with type 2 diabetes can be treated with oral medication, but may also require insulin;
- food care (patient self-care by maintaining food hygiene; wearing appropriate footwear; seeking professional care for ulcer management; and regular examination of feet by health professionals).
