Oats

Some people with coeliac disease may find that eating oats can trigger symptoms. This is because some oats may be contaminated by other grains during production.

Oats also contain a protein called avenin, which is similar to gluten. Most people with coeliac disease can safely eat avenin. However, there's some evidence to suggest a very small number of people may still be sensitive to products that are gluten-free and do not contain contaminated oats.

Increased risk

It's not known why people develop coeliac disease. It also is not clear why some have mild symptoms while others have severe symptoms.

However, the factors described below are known to increase your risk of developing coeliac disease.

Family history

Coeliac disease often runs in families. If you have a close relative with the condition, such as a parent or sibling, your chance of also getting it is increased.

This risk is approximately 10% for those with a family history. If you have an identical twin with coeliac disease, there's a 75% chance you'll also develop the condition.

Research shows 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 something else, such as environmental factors, must trigger coeliac disease in certain people.

Environmental factors

You're more likely to develop coeliac disease if you had a digestive system infection (such as a rotavirus infection) during early childhood.

Also, there's evidence that introducing gluten into your baby's diet before they're 3 months old may increase their risk of developing coeliac disease.

Most experts recommend waiting until your child is at least 6 months old before giving them food containing gluten.

There might also be an increased chance of babies developing coeliac disease if they're not being breastfed when gluten is introduced into the diet.

Read more about your baby's first solid foods.

Other health conditions

A number of other health conditions can increase your risk of developing coeliac disease, including:

• type 1 diabetes
• thyroid conditions 
• 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
• Down's syndrome and Turner syndrome

It's unclear whether these health conditions directly increase your risk of developing coeliac disease, or whether they and coeliac disease are both caused by another, single underlying cause.