Diabetes - Introduction

Diabetes is a common condition. It develops when the amount of glucose in the blood is too high because the body can't use it properly.

Diabetes can lead to serious conditions such as stroke, circulation problems, and damage to the kidneys and eyes. Diabetes UK estimates that nearly 1½ million British people know they have the condition, while another 1 million are unaware of their condition.

Medically known as Diabetes Mellitus, symptoms include thirst, a frequent need to pass urine (especially at night), extreme tiredness, weight loss, genital itching or regular episodes of thrush, and blurred vision. There are three main types: 1, 2 and gestational. Most people with diabetes can handle their condition by a combination of lifestyle and medical interventions. But there is no doubt medical advances need to be made.

What is diabetes?
Diabetes occurs because some people do not make, or cannot respond to, their natural hormone insulin. Hormones help us control the way our bodies work. Insulin's specific job is to regulate the body's use of glucose, our main fuel source. We get glucose, a form of sugar, from the food we eat. It is also made by the liver

Type 1 diabetes
In Type 1 diabetes very little or no insulin is made and lifestyle changes cannot alter the condition. Patients need to monitor their blood glucose levels and administer insulin injections several times daily. This type of diabetes generally develops in younger people, and affects both sexes equally.

Type 1 diabetes develops when cells that make insulin have been destroyed by the body's own immune system. There is a genetic risk to diabetes - it tends to run in families. The environmental factors that might trigger such a destructive process, possibly viral, are not well understood.

Type 2 diabetes
In type 2 diabetes, either the body makes some, but not enough, insulin or it cannot use the insulin it does make. It can usually be controlled through dietary changes and tablets. The treatment of Type 2 diabetes progresses to insulin only if correct blood glucose control cannot be achieved with these two interventions.

Type 2 diabetes is associated with lifestyle factors such as increased weight and a sedentary lifestyle. It used to be called 'late onset' because it usually appears in middle-aged or elderly people. It's also been wrongly described as 'mild' diabetes. There is no such thing. All diabetes should be taken very seriously.

At least three quarters of the estimated 150 million diabetics world-wide have Type 2. It is increasing alarmingly. The World Health Organisation expects numbers to double to over 300 million by 2025.

Gestational diabetes
Pregnancy affects blood glucose levels in all women and, as its name suggests, gestational diabetes is linked to pregnancy. If diagnosis is made during the first three months, then the expectant mother was most probably diabetic already. However, when the diabetes starts after three months, it is thought to be other hormones from the placenta interfering with insulin action.

Diabetes in animals

Insulin, the hormone at the heart of diabetes.

Roughly one in every 500 dogs or cats has diabetes. Onset is usually in older animals, typically over seven for dogs and over five for cats. Burmese cats are known to be genetically predisposed to diabetes. One in ten over eight years' old will develop the disease. Guinea pigs and rabbits also contract the condition. Like humans, some diabetic animals can improve with insulin and a controlled diet. Others need medicines, the ones that were first developed for humans.

What happens when the body cannot control glucose production?
Once inside cells, glucose is converted to energy either to be used immediately or stored as glycogen.

People with diabetes do not have enough insulin or it does not work properly, so their ability to move glucose out of the blood and into tissues, such as muscle, is impaired. The body recognises it lacks energy and stimulates the liver to make more glucose. But the patient's insulin problem means this extra glucose still cannot be used. The next option for the body is break down its stores of protein to try and release yet more, but unfortunately still unusable, glucose. This is why untreated diabetics often feel tired and lose weight. The body gets rid of glucose in the urine, which explains the need to pass large amounts of urine and the extreme thirst from the dehydration that follows.

The impact of diabetes

Foot problems are among the many serious complications that can result from diabetes. Nerve sensations in a patient's foot being tested [CF Fox Valley].

People with diabetes are significantly more likely to develop serious health problems like heart disease, stroke, high blood pressure, circulation problems, nerve damage, and damage to the kidneys and eyes. Disease of their leg arteries greatly increases the risk of exercise pain, gangrene and amputation. Kidney damage, for example, may develop in about one-quarter of all people with the condition, and this can lead to kidney failure and the need for dialysis or kidney transplantation. Diabetes is the single most common cause of blindness in adults of working age. The risks are made even worse if the patient is overweight, smokes or is not physically active. According to one study, diabetes accounts for some 9 per cent of the annual NHS budget.

Thanks are due to Professor Frances Ashcroft (Oxford University), Professor Anthony Barnett (Birmingham Heartlands Hospital), Professor Don Chisholm (Garvan Institute) and Diabetes UK.

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