What is Diabetes?

Everyone with diabetes is different – and not all types of diabetes are the same. 

What is Type 1 diabetes?

Type 1 diabetes is described as an ‘autoimmune’ condition. That’s because it develops when your immune system, which usually protects you from pathogens – organisms that cause disease, like viruses and bacteria – mistakenly attacks and destroys the beta cells that produce insulin in your pancreas, a gland just behind your stomach.3

Insulin is a hormone that moves glucose out of your blood and into the cells of your body, where it’s converted to energy. In Type 1 diabetes, because your body is unable to produce insulin, glucose builds up in the bloodstream but your body’s supply of energy from glucose falls. To make up the shortfall, your body breaks down fat and muscle, a process called ketosis.2 If not treated, this can lead to diabetic ketoacidosis, a life-threatening condition in which glucose levels are dangerously high and excessive levels of toxic compounds called ketones are produced.2

Who gets Type 1 diabetes?

About 8% of people who have diabetes have Type 1.8 Currently about 400,000 people in the UK have been diagnosed, of whom more than 29,000 are children.3 It’s more often diagnosed in children, but adults can also be affected.3 It affects both males and females and isn’t linked to lifestyle factors.1

Father and son

For illustrative purposes only, not real patient

What causes Type 1 diabetes?

Some people who are diagnosed have a family member with Type 1 diabetes but most don’t, so there’s no direct hereditary link.3 Research suggests that certain genes predispose people to develop Type 1, but it’s believed that some other trigger – a virus or an environmental factor – is also required for Type 1 to develop.1

How do I know if I have Type 1 diabetes? 

The symptoms of Type 1 diabetes usually develop quite quickly, over a matter of days or weeks. Most people with Type 1 are diagnosed after becoming acutely unwell and seeking urgent medical help.5 Early signs and symptoms include:6

  • Frequent urination
  • Increased thirst
  • Dry mouth
  • Itchy or dry skin
  • Increased appetite
  • Unexplained weight loss
  • Yeast infections

What’s the treatment for Type 1 diabetes?

As yet there’s no cure for Type 1 diabetes, so the aim of treatment is to keep your glucose levels within a target range you’ll agree with your diabetes care team. This is to prevent short-term problems such as low glucose levels (hypoglycaemia) and high glucose levels(hyperglycaemia). In the long term, avoiding highs and lows and keeping your glucose within range can help prevent complications of diabetes such as problems with your eyes, kidneys and heart.

As your body has stopped producing insulin, you’ll need to have regular doses of insulin, by injecting yourself or through an insulin pump, to keep your glucose levels within range.7

You’ll also need to test your glucose regularly to track how it’s rising and falling in response to your meals, activity and insulin doses. You’ll learn how to match your insulin doses to the food you eat, taking into account your glucose level and how much exercise you do.8

What is Type 2 diabetes?

Type 2 diabetes develops when your body starts to produce less insulin, or the insulin it produces stops working efficiently. It’s quite different from Type 1 diabetes because it isn’t an autoimmune disease that comes on quickly, but develops over many years.8 Type 2 diabetes can be prevented and some people find they can put their condition into remission, which is not the case with Type 1 diabetes.9

Who gets Type 2 diabetes?

About 90% of people who have diabetes have Type 2.8 It’s most often diagnosed in people who are over 40, although it can affect younger people too.8 Men are more likely to develop Type 2 than women.11 People who have a close relative with Type 2 diabetes and people of South Asian, African-Caribbean or Middle Eastern heritage also have a greater risk of developing Type 2.10

What causes Type 2 diabetes?

Unlike Type 1 diabetes, Type 2 diabetes is closely associated with factors such as being overweight – especially carrying excess weight round your waist –being inactive, and having high blood pressure.10 The number of cases of Type 2 diabetes has doubled in 20 years17 and it’s estimated that many cases could be prevented or delayed by adopting healthier lifestyles.18    

How do I know if I have Type 2 diabetes?

It’s believed that 900,000 people in the UK have Type 2 diabetes but haven’t been diagnosed.19 But complications of diabetes can start several years before diagnosis and by the time they find they have Type 2, one in three people will have a complication such as a problem with their eyes, heart, kidneys or nerves.8 It’s important not to ignore symptoms of high glucose levels, such as:6

  • Feeling very thirsty
  • Urinating frequently, particularly at night
  • Feeling very tired
  • Unexplained weight loss

What’s the treatment for Type 2 diabetes?

To start with, most people who are diagnosed with Type 2 diabetes are advised to lose weight if they need to, giving up smoking if appropriate and start exercising regularly.12 This can be enough to manage the condition, and if not there are medications that can help, either by lowering glucose or stimulating insulin production.12 Some people may need to have regular insulin injections if drug treatments don’t control their glucose well enough.12 Some people find that by losing weight, either by a strict supervised diet or weight loss surgery, is enough to put Type 2 into remission.9

What is gestational diabetes?

Gestational diabetes only occurs in pregnancy. It can develop at any stage, but is more common in the second half. Having gestational diabetes increases the risk of complications that can affect your health or your baby’s, such as pre-eclampsia, premature delivery, or having a very large baby.13

What causes gestational diabetes?

Gestational diabetes can develop if the extra hormonal activity required for pregnancy interferes with insulin’s ability to move glucose into your cells, causing glucose levels to rise.14

Who gets gestational diabetes?

You’re more likely to develop gestational diabetes if:13

  • You’re overweight, with a Body Mass Index (BMI) above 30
  • You’ve given birth to a baby weighing more than 4.5kg (9.9lb) in the past
  • You’ve had gestational diabetes before
  • You have a parent, brother, sister or grandparent with Type 2 diabetes
  • You’re of South Asian, African Caribbean or Middle Eastern heritage.

If you're in a higher-risk category, you should be offered a test to check for gestational diabetes.

Pregnant woman doing yoga

What’s the treatment for gestational diabetes?

If you develop gestational diabetes your pregnancy will be carefully monitored and you’ll be advised to eat healthily, take regular exercise and test your glucose before and after meals. You may need medication or insulin injections to manage your glucose levels, and you’ll have extra scans and tests to check your pregnancy is progressing well.13

Gestational diabetes goes away after your baby’s born, but you’re at higher risk of developing Type 2 diabetes later in life if you’ve had gestational diabetes.13

Rarer types of diabetes

Maturity onset diabetes of the young (MODY)

MODY is a rare, inherited form of diabetes affecting approximately 20,000–40,000 people in the UK.15 It’s caused by a genetic modification and is typically diagnosed in people aged 25 or under. There are several forms of MODY, not all of which have typical diabetes symptoms or need treatment with insulin.15 But having MODY increases the risk of long-term diabetes complications so people who’re affected should have regular monitoring and treatment as required.15

Latent Autoimmune Diabetes in Adulthood (LADA)

It’s estimated that about 6-10% of people with Type 2 diabetes actually have LADA, especially those who are diagnosed at a younger age.16 People with LADA develop antibodies that are usually found in Type 1 diabetes, but in other ways LADA is more like Type 2. The treatment for LADA is focused on using medication to control glucose levels and preserve beta cell function in the pancreas.16


1. NHS 2018, About Type 1 diabetes, accessed 21 March 2019, https://www.nhs.uk/conditions/type-1-diabetes/about-type-1-diabetes/.

2. Diabetes UK 2019, Diabetic ketoacidosis (DKA), accessed 21 March 2019, https://www.diabetes.org.uk/guide-to-diabetes/complications/diabetic_ketoacidosis.

3. JDRF 2019, Type 1 diabetes facts and figures, accessed 7 April 2019, https://jdrf.org.uk/information-support/about-type-1-diabetes/facts-and-figures/.

4. Mayo Clinic 2019, Type 1 diabetes, accessed 21 March 2019, https://www.mayoclinic.org/diseases-conditions/type-1-diabetes/symptoms-causes/syc-20353011.

5. American Diabetes Association 2003, Standards of medical care for patients with diabetes mellitus, Diabetes Care, Jan, 26(suppl 1): s33-s50, accessed 21 March 2019 from http://care.diabetesjournals.org/content/26/suppl_1/s33.full.

6. JDRF 2019, Early signs and symptoms of T1 diabetes, accessed 21 March 2019, https://www.jdrf.org/t1d-resources/about/symptoms/.

7. National Institute for Health & Care Excellence 2015, Treatment summary. Type 1 diabetes, accessed 21 March 2019, https://bnf.nice.org.uk/treatment-summary/type-1-diabetes.html.

8. Diabetes UK 2019, Facts and stats January 2019, accessed 21 March 2019, https://www.diabetes.org.uk/professionals/position-statements-reports/statistics.

9. Diabetes UK 2019, Diabetes remission, accessed 21 March 2019, https://www.diabetes.org.uk/guide-to-diabetes/managing-your-diabetes/treating-your-diabetes/type2-diabetes-remission.

10. Diabetes UK 2019, Diabetes risk factors, accessed 21 March 2019, https://www.diabetes.org.uk/preventing-type-2-diabetes/diabetes-risk-factors.

11. NHS 2011, Men more likely to develop diabetes, accessed 21 March 2019, https://www.nhs.uk/news/diabetes/men-develop-diabetes-more-easily/.

12. National Institute for Health and Care Excellence 2015, Treatment summary. Type 2 diabetes, accessed 21 March 2019, https://bnf.nice.org.uk/treatment-summary/type-2-diabetes.html/.

13. NHS 2019, Gestational diabetes, accessed 21 March 2019, https://www.nhs.uk/conditions/gestational-diabetes/treatment/.

14. Tommy's 2015, Causes of gestational diabetes, accessed 21 March 2019, https://www.tommys.org/pregnancy-information/pregnancy-complications/gestational-diabetes/causes-gestational-diabetes/.

15. Diabetes UK 2019, Maturity onset diabetes of the young (MODY), accessed 7 April 2019, https://www.diabetes.org.uk/diabetes-the-basics/other-types-of-diabetes/mody/.

16. NHS Highland 2019, Understanding diabetes, accessed 7 April 2019, https://www.nhshighland.scot.nhs.uk/yourhealth/diabetes/pages/understandingdiabetes.aspx.

17. Diabetes UK 2019, Tackling the crisis, accessed 7 April 2019, https://www.diabetes.org.uk/resources-s3/2019-04/Diabetes%20UK%20Tackling%20the%20Crisis.pdf?/.

18. Diabetes UK 2019, Number of people with diabetes reaches 4.7 million, accessed 7 April 2019, https://www.diabetes.org.uk/about_us/news/new-stats-people-living-with-diabetes/.

19. Diabetes UK 2019, Diabetes, the basics, accessed 28 May 2019, https://www.diabetes.org.uk/diabetes-the-basics/.



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