Autoimmune condition
Coeliac disease is caused by an intolerance to gluten, a protein found in foods such as bread, pasta, cereals and biscuits. Some people with coeliac disease find that eating oats can also trigger their symptoms.
If you have coeliac disease, eating gluten results in damage to your intestines (gut). This happens because coeliac disease is an autoimmune condition.
Autoimmune conditions cause your immune system to mistake healthy cells and substances for harmful ones, and to produces antibodies against them. Usually, antibodies fight off harmful foreign bodies, such as bacteria and viruses.
The surface of the gut lining is usually covered with millions of tiny tube-shaped growths called villi. Villi increase the surface area of your gut and help it to digest food more effectively. However, in coeliac disease, the damage and inflammation to the lining of your gut flattens the villi, which reduces their ability to help with digestion.
As a result, your gut is no longer able to digest all the nutrients you need from the food you eat. This leads to the symptoms of coeliac disease, including diarrhoea and weight loss.
Risk factors
It is not known exactly why people develop coeliac disease, or why some people have very mild symptoms while others have severe symptoms.
However, a number of risk factors have been identified that increase your risk of developing coeliac disease. These are outlined below.
Family history
Coeliac disease often runs in families. If you have a close relative who has the condition, such as a parent, brother or sister, your chance of developing coeliac disease is higher.
The risk of developing coeliac disease if you have a close relative with it is approximately 10%, compared with 1% for someone without a close relative with coeliac disease. If you have an identical twin with coeliac disease, there is an 85% chance that you will also develop the condition.
Research shows that coeliac disease is strongly associated with a number of genetic mutations (abnormal changes to the instructions that control cell activity) that affect a group of genes called the HLA-DQ genes. HLA-DQ genes are responsible for the development of the immune system, and may be passed down through a family.
However, mutations in the HLA-DQ genes are common and occur in about one-third of the population. This suggests that other factors must trigger the onset of coeliac disease in certain people, such as environmental factors.
Environmental factors
Suggested environmental factors for coeliac disease include:
- previous infection of the digestive system, such as a rotavirus infection (a common cause of stomach infections in children)
- diet during early childhood
A recent Government committee looked at the evidence about what effect gluten had in the diet of babies in relation to coeliac disease.
They concluded that there is evidence that introducing gluten into your baby’s diet before they were three months old may increase their risk of developing coeliac disease.
Most experts recommended that you wait until your child is at least six months old before introducing gluten into their diet.
There might also be an increased chance of babies developing coeliac disease if they are not being breastfed when gluten is introduced into the diet
There is more information about the committee’s findings on the Food Standards Agency website.
Other health conditions
A number of other health conditions can increase your risk of developing coeliac disease. Health conditions associated with coeliac disease include:
- type 1 diabetes
- ulcerative colitis, a digestive condition that causes inflammation of the colon (large bowel)
- neurological disorders, which affect the brain and nervous system, such as epilepsy (a condition where a person has repeated fits or seizures)
See Coeliac disease – diagnosis for a more extensive list of conditions associated with coeliac disease.
It is unclear whether these health conditions are independent risk factors for developing coeliac disease, or whether they and coeliac disease are both caused by another, single underlying cause.
