Around 3 million people in the UK have diabetes – and the number is growing. Find out what causes type 1 and type 2 diabetes and if obesity is to blame.
Medically reviewed by Dr Juliet McGrattan (MBChB) and Based on a text by Dr Jan Erik Henriksen, Dr Ole Hother Nielsen, Professor Henning Beck-Nielsen
Concerned about diabetes? In the UK, around 90 per cent of all adults with diabetes have type 2. Here’s everything you need to know about Type 1 diabetes and Type 2 diabetes including causes, symptoms treatment and management tips:
What is diabetes?
Diabetes is a long-term condition in which the blood sugar level in the body is higher than normal. There are two main types of diabetes:
- Type 1 diabetesor insulin-dependent diabetes. It usually (although not exclusively) begins in young people.
- Type 2 diabetesor non insulin-dependent diabetes. It tends to affect adults over 40 and overweight people, although it is now becoming commoner amongst younger people. Type 2 diabetes occurs more frequently in people of South Asian and African-Caribbean descent. There are also other types of diabetes.
Diabetes in pregnancy
Women can develop diabetes during pregnancy. Gestational diabetes, as it is sometimes referred to, usually disappears after the birth of the baby. However, having gestational diabetes increases the risk of type 2 diabetes later in life.
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Existing type 1 diabetes may be exacerbated during pregnancy.
This is when diabetes is caused as the result of another condition, eg inflammation of the pancreas, or by the use of certain medication such as diuretics or steroids (the most common cause).
How common is diabetes?
Currently over 3 million people in the UK have diabetes, ninety percent of which have the type 2. It is estimated that more than half a million people more in the UK have type 2 diabetes, but are unaware of it.
The last 30 years has seen a threefold increase in the number of cases of childhood diabetes. This is especially worrying in respect of the rising numbers of children and teenagers with Type 2 diabetes, which was once only seen in older people. This trend is likely to reflect the rising obesity levels in young people over the same time period. There has also been an increase in the number of children with Type 1 diabetes, the cause of which is unclear.
What causes diabetes?
Glucose is sugar. Blood sugar level is the same as blood glucose level. Insulin is a hormone that is produced by the pancreas gland in the abdomen. It controls the use of glucose within the body.
The blood sugar level in the body will rise if the following occurs:
- The pancreas produces little or no insulin(leading to type 1 diabetes).
- The pancreas produces insulin, but it’s inadequate for the body’s needs and its effectiveness is reduced (leading to type 2 diabetes).
It is thought that the development of type 2 diabetes is related to factors associated with an increasingly sedentary Western lifestyle and diet, since it’s most common in people who don’t get enough exercise or are overweight.
Gestational diabetes is brought about by the many hormone changes and demands placed upon the body during pregnancy.
Secondary diabetes is much like Type 2 diabetes. It’s quite variable, depending on the underlying cause. It can be caused by damage to the pancreas (eg by alcohol), and drugs such as steroids and diuretics can impair insulin secretion from the pancreas.
Common diabetes symptoms
Glucose is one of the body’s main fuels. If there isn’t enough insulin in the body, blood sugar levels rise and glucose is secreted into urine.
If you experience any of these symptoms on a regular basis, see your GP and get tested for diabetes:
- Increased thirst
- Frequent urination
- Weight loss, although appetite often increases (especially in Type 1 diabetes)
- Itchiness, especially around the genitals or genital thrush
- Recurrent infections on the skin, eg boils or urinary infection
People with type 1 diabetes usually develop these symptoms within days or weeks. In type 2 diabetes, these symptoms often don’t become apparent for years. Many people are diagnosed with diabetes by chance through routine medical check-ups.
Genetics play a part in diabetes. 10 per cent of people with type 1 diabetes have a family history of diabetes, while 30 per cent of people with type 2 diabetes have a family history of the condition.
People with Type 2 diabetes often have the following:
- A family history of diabetes
- Increased blood pressure
- Premature vascular problems such as heart attacksand stroke
- A raised level of triglyceride (a type of fat) in the blood
- Impotence (erectile dysfunction).
Glucose levels are measured with a blood test:
Random glucose test
Glucose levels are taken at a random time on two occasions. Any figure equal to or above 11.1mmol/l suggests a diagnosis of diabetes
Fasting glucose test
The glucose level is measured after an overnight fast and on two different days. Above 7.0mmol/l suggests a diagnosis of diabetes
A glycated haemoglobin (HbA1c) test
This is a blood test used to monitor diabetes, but can now also be used to diagnose diabetes. HbA1c below 42 mmol/mol is normal, between 42 and 47 mmol/mol suggests high risk of developing diabetes, and over 48 mmol/mol on two occasions (in someone with no symptoms) will diagnose diabetes.
You may only need to give one blood sample if you have other symptoms of diabetes but it’s usual to double check to confirm the diagnosis.
Glucose tolerance test
If the diagnosis is still unclear from these tests, a glucose tolerance test can be carried out. During this test, a glucose drink is given containing a standard amount of glucose (75g). Blood samples are taken before the drink is given and two hours later. The test is done after an overnight fast.
The following parameters are used to confirm a diagnosis of diabetes after a glucose tolerance test:
- A two-hour blood glucose level equal to or above 11.1mmol/l is a diagnosis of diabetes.
- A level below 7.8mmol/l is normal.
What if I have IGT?
If the level falls between these values, it suggests a decreased tolerance for glucose. This is known as impaired glucose tolerance (IGT). Impaired glucose tolerance is more than just a pre-diabetic state.
People who have IGT are at increased risk of developing some of the conditions associated with diabetes, such as heart disease. Pregnant women with IGT have an increased risk of miscarriage and stillbirth.
If you have IGT, you should take similar steps to people with diabetes:
- Lose weightif you are overweight – a 6 to 7 per cent weight loss will reduce you chance of developing diabetes by around 58 per cent over 5 years
- exercise more
- Stop smoking.
You should also be kept under review and checked at least annually for the development of diabetes.
A HbA1c level of between 42-47 mmol/mol is called ‘at risk diabetes’ or ‘pre-diabetes’, and also indicates a high risk for developing diabetes. Weight loss can help reduce this risk.
Diabetes is treated in two ways:
Diet and diabetes
A special diet used to be recommended for diabetes. It’s now thought a normal, well-balanced diet is best – but calorie intake is still important.
People with diabetes who are overweight need to incorporate weight loss as part of their treatment.
- A combination of healthy diet and exercise – aim to reduce dietary intake of fat, salt, and sugar, increase intake of fruit and vegetables, and consume mainly low glycaemic index foods. A minimum of 150 minutes of moderate intensity exercise should be undertaken each week.
- Medication with tablets and/or insulin.
Insulin injections increase the amount of insulin in your body and bring down the blood sugar level. Insulin injections are used in all people with type 1 diabetes and in some people with type 2.
Insulin injections can be given once a day as a long-acting insulin, or as shorter-acting injections given more frequently through the day with meals, and can be used in combination with tablet treatment if necessary.
There are different types of oral medication for treating type 2 diabetes:
- Some increase the amount of insulin secreted by the pancreas
- Some increase the action of insulin in the body
- Some delay the absorption of glucose from the digestive system
- Some suppress a hormone called glucagon, which is secreted by the pancreas and stops insulin from working
- Some increase the amount of glucose lost in the urine, hence lowering blood glucose levels and aiding weight loss.
Treatment for diabetes depends on the individual. It starts the first time you give yourself an insulin injection or take a diabetes tablet, and continues through eating a well-balanced diet and starting an exercise programme.
Diabetes help and support
To help you get the most out of treatment, consult your diabetes care team at your local GP or hospital. You should be able to access diabetes education classes, which are run in most areas now. These classes will aid your understanding of diabetes and help you manage the condition yourself.
In addition to treating high blood glucose levels, it is extremely important that people with diabetes have their blood pressure and blood cholesterol levels well controlled to reduce their risk of complications.
Blood sugar levels
Monitoring blood sugar levels is an important aspect of treatment, especially in Type 1 diabetes where levels can change markedly. This can be done easily at home with a small blood glucose meter. Depending on the reading, you may need to adjust your diet, the amount you exercise or your insulin intake.
In people with type 2 diabetes, glucose testing is only required if you take insulin. People with type 2 diabetes don’t need to have regular glucose tests unless they take insulin.
In the long term, diabetes is monitored through routine check-ups by your diabetes care team at your GP or hospital. Their purpose is to determine if your treatment is satisfactory and to look out for any evidence of longer-term complications, such as eye or kidney problems.
Tests for these complications are usually done at an annual check-up, while routine check-ups may be carried out every three to six months.
Diabetes routine check-ups
You may expect the following during a routine check-up:
- Blood sample to check the level of HbA1c (a measure of long-term glucose) in the blood.
- Evaluation of home glucose readings if needed.
- Discussion of diet.
- Blood pressure.
- Weight check.
- Other tests and examinations as determined by your doctor.
Diabetes annual check-ups
You may expect the following during an annual check-up:
- Blood test to check the level of HbA1c. Your level of HbA1c depends on your age and other medical problems. An approximate HbA1c level of 53 mmol/mol is deemed good control, but this target should tailored to the individual
- Blood sample to determine the amount of fats (cholesterol) in the blood. Cholesterol should ideally be below 4.0 mmol/L.
- Blood sample to check kidney function and various salts in the blood (mainly sodium and potassium).
- Blood pressure – most people with diabetes should have a blood pressure of under 140/80mmHg
- Urine sample to determine the presence of protein (albuminuria). The appearance of protein in the urine can indicate that the small blood vessels (capillaries) in the kidneys are beginning to be affected by the diabetes
- Foot examination, including a check of various pulse points on the foot to assess circulation and a check for vibration sensation to determine if there’s any neuropathy (nerve damage) to the foot
- Weight check
- Discussion of exercise habits
- Discussion of smoking habits
- Eye check – this is not just a check to see if you need glasses, this is a proper check of the retina (back of the eye), usually done by digital photography at a hospital/medical centre or an optician practice. This will be part of an accredited diabetic retinal screening programme and you will be invited to attend – ask your diabetes team about this.
Diabetes long-term prospects
Type 1 and type 2 diabetes both carry a risk of complications, but this risk is dramatically reduced if your diabetes, blood pressure and cholesterol levels are well controlled and if you abstain from smoking.
Diabetes acute complications
The acute complications of diabetes include:
- Low glucose level (called a hypoglycaemic attack or ‘hypo’), caused by treatment with insulin or oral hypoglycaemicdrugs that increase insulin secretion from the pancreas
- Diabetic ketoacidosis, a life-threatening condition caused by the lack of insulin. This occurs mainly in type 1 diabetes, but a similar high-glucose emergency can occur in Type 2.
Late-stage diabetic complications
Late-stage complications of diabetes include:
- Retinopathy(eye disease) – this causes blindness in rare cases.
- Diabetic kidney disease, which can lead to kidney failure
- Diabetic neuropathy(nerve disease), which can cause foot ulcers and infections.
- Atherosclerosis(hardening of the arteries) – this happens in smokers, particularly, and those with high blood pressure and abnormal fat levels in the blood.
Late-stage complications do not usually develop for 10 to 15 years in people with type 1 diabetes.
In people with type 2 diabetes, however, symptoms can appear close to the time of actual diagnosis because the disease may go undetected for longer.
Many studies now show that good glucose control can significantly reduce or even stop complications. This involves keeping the blood sugar level as close to normal as possible.
Recent studies have also confirmed the need for people with diabetes to reduce their risk of atherosclerosis.
The main factors that increase your risk are:
- High blood pressure
- Raised levels of fats such as cholesterolin the blood.
By taking measures to address these issues, you will reduce your chance of developing complications such as heart disease.