What is type 2 diabetes and how is it diagnosed?

Diabetes affects over four million people in the UK and nine out of every 10 with the condition have type 2 diabetes. Although type 2 diabetes usually occurs in adults aged over 40, in recent years cases in younger people, including children, have become more common. 

Type 2 diabetes occurs when levels of glucose (sugar) in your blood are too high as a result of your body’s cells not responding to the hormone insulin or your pancreas not making enough insulin. 

In a healthy body, when your blood glucose levels rise (eg after eating or drinking a sugary drink) your pancreas makes insulin, which tells your cells to absorb glucose in your blood for use or storage. When this doesn’t happen, your blood glucose levels remain high, causing diabetes. Over time, this damages multiple tissues and organs. 

Your risk of type 2 diabetes is higher if you have close family members (eg a parent or sibling) with the condition, are of Asian, Afro-Caribbean or black African descent, are overweight and/or lead a sedentary lifestyle. 

Your risk is also raised if you have metabolic syndrome, polycystic ovary syndrome or prediabetes, where your blood glucose levels are high but not high enough to be considered diabetic.

Symptoms of type 2 diabetes

Depending on how high your blood glucose levels are and how long you have had type 2 diabetes, the severity of your symptoms will vary. As symptoms develop gradually, you may not initially notice any obvious changes. 

Common symptoms include urinating more often than usual, especially at night, always feeling thirsty and feeling tired. 

You may also notice that any cuts or wounds take longer to heal, your genitals are itchy and/or you frequently develop thrush.

Unintentional weight loss, blurred vision, constipation, hiccups, bad breath, itchy skin and night sweats are also symptoms of type 2 diabetes. 

If you notice any of these symptoms, it is important to see your GP. 

How type 2 diabetes is diagnosed

Your GP will ask you about your symptoms and then ask for a urine sample for a dipstick test, where a special strip of paper is dipped into your urine. The strip will change colour if there is glucose in your urine. However, this is not a definitive test for diabetes, as it doesn’t reveal how much glucose is in your urine or indicate why it’s there. 

For a clear diagnosis, you will also need a blood test. There are three main blood tests used for diagnosing diabetes: 

• A1c test — your blood will be tested for glycated haemoglobin (HbA1c), a protein that indicates your average blood glucose levels over the last few months; a result of 48 mmol/mol (6.5%) or above means you have diabetes 
• Fasting blood glucose test — after fasting for eight hours (ie not eating or drinking anything except water), your blood will be tested for glucose; a result of 7.0 mmol/l or above means you have diabetes 
• Oral glucose tolerance test — your blood will be tested for glucose after fasting for eight hours and again two hours after having a sugary drink; a fasting blood glucose level of 7.0 mmol/L or above and 11.0 mmol/L or above two hours after your sugary drink means you have diabetes

Random blood glucose tests to check your glucose levels can be performed at any time (eg if you present with severe diabetes symptoms) but are not used for diagnosis.

If your blood test results show that you have diabetes, depending on your age and symptoms, you may need further tests to determine if you have type 1 or type 2 diabetes eg if type 1 diabetes is suspected, you may need a blood test for autoantibodies. 

What is the difference between type 1 and type 2 diabetes?

Type 1 diabetes is much less common than type 2 diabetes and accounts for around 8% of all cases of diabetes in the UK. Unlike type 2 diabetes, it doesn’t develop gradually with age but develops quickly, usually in childhood. It is an autoimmune condition, which means your body mistakenly attacks and destroys healthy cells, in this case, the cells in your pancreas that make insulin (beta cells). 

Unlike type 2 diabetes, which can be managed through diet and lifestyle changes, type 1 diabetes requires taking insulin several times a day. 

There is currently no cure for type 1 or type 2 diabetes. However, type 2 diabetes can be prevented and can go into remission ie when your blood sugar levels return to healthy levels for the long term without needing to take any medication. 

What happens after diagnosis?

If you have been diagnosed with type 2 diabetes, your doctor will explain what this means and how high blood glucose levels can affect your life. They will let you know whether or not you need to take medication and discuss lifestyle and dietary changes to help treat your diabetes. 

They will also let you know about the complications that diabetes can cause and the signs you need to look out for. 

You will be referred to a diabetes care team for regular check-ups, which will involve having the A1c blood test every three months until your blood glucose levels stabilise and then every six months after that. 

You will also have an annual examination to check on the health of your feet and eyes, and to test for high blood pressure, heart disease and kidney disease. 

Complications of type 2 diabetes

Type 2 diabetes can affect multiple tissues and organs, and consequently increases your risk of several other diseases. 

It can damage your nerves causing neuropathy. Signs of neuropathy include tingling, burning sensations, numbness and pain in affected areas. This usually starts at your extremities, in your fingers and toes, and spreads from there. 

Nerve damage can also cause gastrointestinal problems, such as constipation, diarrhoea, nausea and vomiting, as well as irregular heart rhythms (arrhythmia). 

Type 2 diabetes is also associated with high blood pressure, heart disease, narrowing of your blood vessels (atherosclerosis) and stroke. It can damage the blood vessels that supply your eyes, leading to the eye disease diabetic retinopathy, which can cause vision loss, and the blood vessels that supply your kidneys, leading to kidney disease.

Additionally, your ability to heal can be impaired by type 2 diabetes, which increases the chances of cuts and blisters becoming infected.  

Other complications of type 2 diabetes in men include difficulty getting or maintaining an erection (erectile dysfunction), and in pregnant women, miscarriage and stillbirth. 

Treating type 2 diabetes

Dietary and lifestyle changes are central to treating type 2 diabetes. This includes exercising regularly, losing any excess weight, quitting smoking and following a healthy, balanced diet with limited amounts of food that are high in salt, fat and sugar. A dietitian can advise you on how best to adapt your diet. You should also avoid skipping meals and try to eat your meals at regular times. 

Although in some cases lifestyle and dietary changes are enough to manage type 2 diabetes, most people also need to take medication. There are different types of medication and you may need to try several before you find the one that works best for you. The dosage and type of medication may also need to change in the future depending on whether or not your type 2 diabetes gets worse. 

The most common medication initially prescribed for type 2 diabetes is metformin. You may end up needing several different types of medication. In most cases, insulin is not prescribed unless all other medications haven’t been successful. 

If you do need to take insulin, your GP or nurse will show you how to inject yourself with insulin or how to use an insulin pump. 

Diabetes medications are available on free prescriptions. Your GP practice will provide you with a PF57 form which will exempt you from paying for your diabetes medication prescriptions. 

Preventing type 2 diabetes

You can reduce your risk of developing type 2 diabetes by following a healthy, balanced diet that is low in salt, fat, sugar and highly processed foods. Regular exercise, losing excess weight, not smoking and ensuring you drink no more than 14 units of alcohol per week will also reduce your risk.