Medline Plus describes diabetes as a disorder of metabolism – the way our bodies use digested food for growth and energy. Most of the food we eat is broken down into glucose, the form of sugar in the blood. Glucose is the main source of fuel for the body.
After digestion, glucose passes into the bloodstream, where it is used by cells for growth and energy. For glucose to get into cells, insulin must be present. Insulin is a hormone produced by the pancreas, a large gland behind the stomach.
When we eat, the pancreas automatically produces the right amount of insulin to move glucose from blood into our cells. In people with diabetes, however, the pancreas either produces little or no insulin, or the cells do not respond appropriately to the insulin that is produced. Glucose builds up in the blood, overflows into the urine, and passes out of the body in the urine. Thus, the body loses its main source of fuel even though the blood contains large amounts of glucose.
There are two main types of diabetes:
Type 1 Diabetes
Type 1 diabetes develops if the body is unable to produce any insulin. This type of diabetes usually (but not always) appears before the age of 40. Type 1 diabetes is the less common of the two main types and accounts for between 5 – 15% of all people with diabetes.
Type 1 diabetes is an autoimmune disease. An autoimmune disease results when the body’s system for fighting infection (the immune system) turns against a part of the body. In diabetes, the immune system attacks and destroys the insulin-producing beta cells in the pancreas. The pancreas then produces little or no insulin. A person who has type 1 diabetes must take insulin daily to live.
At present, scientists do not know exactly what causes the body’s immune system to attack the beta cells, but they believe that autoimmune, genetic, and environmental factors, possibly viruses, are involved.
Symptoms of type 1 diabetes usually develop over a short period, although beta cell destruction can begin years earlier. Symptoms may include increased thirst and urination, constant hunger, weight loss, blurred vision, and extreme fatigue. If not diagnosed and treated with insulin, a person with type 1 diabetes can lapse into a life-threatening diabetic coma, also known as diabetic ketoacidosis.
Type 2 Diabetes
Type 2 diabetes develops when the body can still make some insulin, but not enough, or when the insulin that is produced does not work properly (known as insulin resistance). In most cases this is linked with being overweight, and can also run in families. This type of diabetes most often appears in people over the age of 40. It is the most common of the two main types and accounts for between 85 – 95% of all people with diabetes. About 80 percent of people with type 2 diabetes are overweight. There are currently over 2 million people with diabetes in the UK and there are up to another 750,000 people with diabetes who have the condition and don’t know it.
When type 2 diabetes is diagnosed, the pancreas is usually producing enough insulin, but for unknown reasons the body cannot use the insulin effectively, a condition called insulin resistance. After several years, insulin production decreases. The result is the same as for type 1 diabetes—glucose builds up in the blood and the body cannot make efficient use of its main source of fuel.
This form of diabetes usually begins with insulin resistance, a condition in which fat, muscle, and liver cells do not use insulin properly. At first, the pancreas keeps up with the added demand by producing more insulin. In time, however, it loses the ability to secrete enough insulin in response to meals.
The symptoms of type 2 diabetes develop gradually. Their onset is not as sudden as in type 1 diabetes. Symptoms may include fatigue, frequent urination, increased thirst and hunger, weight loss, blurred vision, and slow healing of wounds or sores. Some people have no symptoms. Approximately 15% of people older than 70 have type 2 diabetes. We also note that about 65 percent of deaths among those with diabetes are attributed to heart disease and stroke.
Both kinds of diabetes can lead to a number of serious conditions, so it is extremely important that you manage it carefully to reduce the risks. Lifestyle changes, your own vigilance and medical help can make all the difference.
Pre-diabetes is a condition to be taken seriously. People with pre-diabetes have blood glucose levels that are higher than normal but not high enough for a diagnosis of diabetes. This condition raises the risk of developing type 2 diabetes, heart disease, and stroke.
Pre-diabetes is also called impaired fasting glucose (IFG) or impaired glucose tolerance (IGT), depending on the test used to diagnose it. Some people have both IFG and IGT. IFG is a condition in which the blood glucose level is high after an overnight fast, but is not high enough to be classified as diabetes.
IGT is a condition in which the blood glucose level is high after a 2-hour oral glucose tolerance test, but is not high enough to be classified as diabetes. Many people with pre-diabetes go on to develop type 2 diabetes within 10 years.
If your doctor finds you have a pre-diabetic condition, get to work on it. Medline Plus tells us the good news is that if you have pre-diabetes you can take effective steps to prevent or delay diabetes. Studies have clearly shown that you can lower your risk of developing diabetes by losing 5 to 7 percent of your body weight through diet and increased physical activity. A major study of more than 3,000 people with IGT, a form of pre-diabetes, found that diet and exercise resulting in a 5 to 7 percent weight loss – about 10 to 14 pounds in a person who weighs 200 pounds – lowered the incidence of type 2 diabetes by nearly 60 percent. Study participants lost weight by cutting fat and calories in their diet and by exercising (most chose walking) at least 30 minutes a day, 5 days a week. Type 1 and Type 2 diabetes are classified as Diabetes Mellitus.
The word diabetes is derived from Greek and means, “a syphoning of water through the body”. Insipidus is a Latin word meaning tasteless. The name Diabetes Mellitus implies that patients with this condition lose large amounts of urine which is sweet and full of sugar, whereas in the case of Diabetes Insipidus the urine, although passed in excess, does not contain sugar. Diabetes Insipidus is not related to Diabetes Mellitus except that patients with either condition are thirsty and pass a lot of urine. In the case of Diabetes Insipidus increased amounts of urine are passed because the body cannot retain water; the body has normal amounts of sugar and insulin. The inability to retain water is usually due to a shortage of a hormone called antidiuretic hormone (ADH, sometimes called vasopressin), which is made by the pituitary gland situated underneath the brain. Occasionally normal amounts of ADH are present, but the kidneys are not able to use it properly.
Diabetes Insipidus is much less common than Diabetes Mellitus. In many cases there is no obvious cause for the inability of the pituitary gland to make ADH. In other people an inflammation, infection around the pituitary gland or a head injury may lead to the loss of ADH secretion. Operations on the pituitary gland may also lead to Diabetes Insipidus, but as in the case of a head injury, this is often temporary.
Diabetes Insipidus (unlike Diabetes Mellitus) does not usually require treatment with diet, tablets or injections. Instead ADH or ADH-like substances are self administered by the patient in the form of a nasal spray, and this returns the urine flow to normal. Treatment will usually be life-long, and in many cases may require hospital clinic attendance. For help with diabetes insipidus contact The Pituitary Foundation.
Diabetes Signs and Symptoms
The Diabetes UK website tells us that the signs and symptoms of diabetes can include:
- Increased thirst
- Going to the toilet (to urinate) all the time – especially at night
- Extreme tiredness
- Weight loss
- Blurred vision
- Genital itching or regular episodes of thrush
- Slow healing of wounds
In Type 1 diabetes the signs and symptoms will usually be very obvious, developing quickly, usually over a few weeks. In people with Type 2 diabetes the signs and symptoms will not be so obvious or even non-existent. Older people may put the symptoms down to ‘getting on a bit’ – expected downsides of ageing. If you have symptoms, see your doctor. do not delay. Taking early action is key so if any of the symptoms apply to you, ask your GP for a diabetes test. In both types of diabetes, the symptoms are quickly relieved once the diabetes is treated. Early treatment will also reduce the chances of developing serious health problems. You may well be right that you’re simply feeling your age, but find out. It can’t hurt, and it may save you from a great deal of suffering.
Causes and Risk Factors
The Merck Geriatric website tells us that people develop type 2 diabetes because the cells in the muscles, liver, and fat do not use insulin properly. Eventually, the pancreas cannot make enough insulin for the body’s needs. As a result, the amount of glucose in the blood increases while the cells are starved of energy. Over the years, high blood glucose damages nerves and blood vessels, leading to complications such as heart disease, stroke, blindness, kidney disease, nerve problems, gum infections, and amputation.
Research has demonstrated that people at risk for type 2 diabetes can prevent or delay developing type 2 diabetes by losing a little weight. The results of the Diabetes Prevention Program (USA) showed that moderate diet changes and physical activity can delay and prevent type 2 diabetes.
The DPP tested two approaches to preventing diabetes: lifestyle change – a program of healthy eating and exercise – and the diabetes drug metformin. People in the lifestyle change group exercised about 30 minutes a day 5 days a week, usually by walking, and lowered their intake of fat and calories. Those who took the diabetes drug metformin received information on exercise and diet. A third group only received information on exercise and diet.
The results showed that people in the lifestyle change group reduced their risk of getting type 2 diabetes by 58 percent. In the first year of the study, people lost an average of 15 pounds. Lifestyle change was even more effective in those aged 60 and older. They reduced their risk by 71 percent. People receiving metformin reduced their risk by 31 percent.
Risk Factors include:
- A close member of your family has Type 2 diabetes (parent or brother or sister).
- You are overweight.
- You’ve been diagnosed with any problems with your circulation, had a heart attack or stroke, or have high blood pressure.
- You’re a woman with polycystic ovary syndrome and you are overweight.
- You’re a woman who has had gestational diabetes.
- You have severe mental health problems.
- You’re over 40 or you’re over 25 and black, Asian or from a minority ethnic group. The risk rises with age, so the older you get the more at risk you are.
- You’ve been told you have either impaired fasting glycaemia (IFG) or impaired glucose tolerance (IGT)
The more risk factors that apply to you, the greater your risk of having diabetes. Merck Geriatric tells us that Diabetes also may occur in people with excess production of growth hormone (acromegaly) and in people with certain hormone-secreting tumors. Severe or recurring pancreatitis and other diseases that directly damage the pancreas can lead to diabetes.
Merck Geriatric’s website describes the potential serious, long-term complications from diabetes. Some of these complications begin within months of the onset of diabetes, although most tend to develop after a few years. Most of the complications are progressive. The more tightly a person with diabetes is able to control the levels of sugar in the blood, the less likely it is that these complications will develop or become worse.
High sugar levels cause narrowing of both the small and large blood vessels. Complex sugar-based substances build up in the walls of small blood vessels, causing them to thicken and leak. As they thicken, they supply less blood, especially to the skin and nerves. Poor control of blood sugar levels also tends to cause the levels of fatty substances in the blood to rise, resulting in atherosclerosis (see Atherosclerosis in our pages on Heart Conditions) and decreased blood flow in the larger blood vessels. Atherosclerosis is between 2 and 6 times more common in people with diabetes than in people who do not have the disease and tends to occur at younger ages.
Over time, elevated levels of sugar in the blood and poor circulation can harm the heart, brain, legs, eyes, kidneys, nerves, and skin, resulting in angina, heart failure, strokes, leg cramps on walking (claudication), poor vision, renal failure, damage to nerves (neuropathy), and skin breakdown. Heart attacks and strokes are more common among people with diabetes.
Poor circulation to the skin can lead to ulcers and infections, and all wounds heal slowly. People with diabetes are particularly likely to have ulcers and infections of the feet and legs. Too often, these wounds heal slowly or not at all, and amputation of the foot or part of the leg may be needed.
People with diabetes often develop bacterial and fungal infections, typically of the skin. When the levels of sugar in the blood are high, white blood cells cannot effectively fight infections. Any infection that develops tends to be more severe. Damage to the blood vessels of the eye can cause loss of vision (diabetic retinopathy). Laser surgery can seal the leaking blood vessels of the eye and prevent permanent damage to the retina. Therefore, people with diabetes should have yearly eye examinations to check for damage.
The kidneys can malfunction, resulting in kidney failure that may require dialysis or kidney transplantation. Doctors usually check the urine of people with diabetes for abnormally high levels of protein (albumin), which is an early sign of kidney damage. At the earliest sign of kidney complications, the person is often given angiotensin-converting enzyme (ACE) inhibitors, drugs that slow the progression of kidney disease.
Damage to nerves can manifest in several ways. If a single nerve malfunctions, an arm or leg may suddenly become weak. If the nerves to the hands, legs, and feet become damaged (diabetic polyneuropathy), sensation may become abnormal, and tingling or burning pain and weakness in the arms and legs may develop. Damage to the nerves of the skin makes repeated injuries more likely because the person cannot sense changes in pressure or temperature.
The foot in Diabetes: Diabetes causes many changes in the body. The following changes in the feet are common and difficult to treat.
Neuropathy (damage to the nerves) affects sensation to the feet, so that pain is not felt. Irritation and other forms of injury may go unnoticed; an injury may wear through the skin before any pain is felt.
Other changes in sensation alter the way people with diabetes carry weight on their feet, concentrating weight in certain areas so that calluses form. Calluses (along with dry skin) increase the risk of skin breakdown. Diabetes can cause poor circulation in the feet, making it more likely that ulcers will form when the skin is damaged and making the ulcers slower to heal.
In addition to the changes in the foot, diabetes can affect the body’s ability to fight infections. Therefore, once an ulcer forms, it easily becomes infected; the infection may become serious and difficult to treat, leading to gangrene. People with diabetes are more than 30 times more likely to require an amputation of a foot or leg than are people without diabetes.
Foot care is critical. The feet should be protected from injury, and the skin should be kept moist with a good skin moisturiser. Shoes should fit properly and not cause areas of irritation. Shoes should have appropriate cushioning to spread out the pressure caused by standing. Going barefoot is ill advised. Regular care from a podiatrist, such as having toenails cut and calluses removed, may also be helpful. Also, sensation and blood flow to the feet should be regularly evaluated by a doctor.
From women with diabetes there may be additional complications regarding menopause, osteoporosis and menstrual irregularities. Given the impact of the long and incomplete list above, we’ll repeat Merck’s advice: The more tightly a person with diabetes is able to control the levels of sugar in the blood, the less likely it is that these complications will develop or become worse.
People with diabetes benefit enormously from learning about the disease, understanding how diet and exercise affect their blood sugar levels, and knowing how to avoid complications.