Glucose is always present in the blood to give the body energy.
The body will regulate the blood glucose level via a mechanism called “homeostasis” to ensure levels don’t rise or fall to dangerous levels.
Excess glucose from food (carbohydrates) will be stored in the liver, ready to be released into the blood when levels drop.
The pancreas produces a hormone called “insulin” which acts like a key, unlocking the body’s cells allowing them to take up the glucose out of the blood and use it for energy.
In a person with “pre-diabetes” or “Impaired Glucose Regulation” (IGR):
This is where blood glucose levels are above normal but not high enough to be given a diagnosis of diabetes.
It is unlikely that medication would be given at this point and risk can be reduced by nearly 60% through lifestyle changes (2, 3).
More than 70% of people with IGR may eventually go on to develop Type 2 diabetes (4).
In a person with diabetes:
Type 1 diabetes:
It is an autoimmune process where the body attacks its own insulin producing cells in the pancreas. The cause for this is unknown, but there are theories around certain triggers, such as viruses and trauma (5, 6).
It is associated with other autoimmune conditions such as coeliac disease, rheumatoid arthritis, hypothyroidism, etc.
There may be a genetic link in some cases, with first degree relatives having a 15 fold increased risk, although 85% of people with the condition will have no family history of the condition.
In type 1 diabetes, the pancreas ceases to produce any insulin at all.
The only treatment is to replace the insulin (most commonly via injections or insulin pumps). Inhalable insulins aren’t currently approved for use in the UK.
It is usually diagnosed in children and young adults where it develops very quickly.
Type 2 diabetes:
It tends to develop in people over the age of 40 but due to growing waistlines and sedentary lifestyles, we are seeing younger people and even children being diagnosed.
Lifestyle factors, particularly carrying excess weight, can increase the risk of developing Type 2 diabetes.
Too much fat (especially around the tummy) stops insulin doing its job properly, known as ‘insulin resistance’.
A 1cm increase in waist circumference will increase the risk of type 2 diabetes by 3.5% (7).
The pancreas tries to compensate by producing more insulin, but over time can exhaust itself so it also starts to produce less insulin.
Treatment often starts with advice around lifestyle changes (losing weight if applicable, healthy eating and physical activity) with or without tablets and may progress onto other injectable medication and insulin.
Type 2 diabetes is also a genetic condition and ethnicity also plays a role. Those from a South Asian, African-Caribbean, Black African, or Chinese background are at higher risk of developing Type 2 diabetes.
Gestational diabetes develops in pregnancy, normally in the second or third trimester.
It occurs due to changes in hormones, and usually disappears following birth of baby and placenta, unless there was undiagnosed pre-existing diabetes.
It is more common in women who are overweight, have a family history of diabetes or who are from a certain ethnic background, or those who have had gestational diabetes before.
It is important to achieve tight blood glucose control to prevent complications occurring during pregnancy and labour, such as baby growing too large, premature birth or baby’s blood sugar dropping too low after birth.
Risks to mothers include high blood pressure and pre-eclampsia. Some women can control their blood glucose with dietary changes alone but further treatment is also often required in the form of tablets or insulin.
Latent Autoimmune Diabetes in Adults (LADA):
Characteristic of type 1 diabetes but tends to develop in older adults with a slightly slower progression and can therefore sometimes be misdiagnosed as type 2 diabetes.
Treatment will still need to be insulin due to cessation of any pancreatic insulin production.
Diabetes that develops due to another disorder, for example, pancreatitis, pancreatectomy (removal of the pancreas), cystic fibrosis, or medication (such as steroids).
Maturity Onset Diabetes of the Young (MODY):
A genetic form of diabetes which is much rarer but runs strongly in families.
There are multiple forms of MODY depending on the gene affected, which may be identified via genetic testing to determine the most appropriate treatment from lifestyle alone to tablets or Insulin.