What is coeliac disease?

What is it?

Coeliac disease is a lifelong immune illness affecting at least an estimated 1 in 100 (1.1%–1.7%) people worldwide. The condition arises in genetically predisposed individuals following the ingestion of gluten, a composite of proteins found in grains such as wheat, barley, and rye. For individuals with coeliac disease, consuming gluten causes an immune reaction which damages the lining of the small bowel (i.e. villous atrophy) and typically results in various intestinal and/or non-intestinal symptoms (e.g. diarrhoea, abdominal pain, headache, fatigue). The type and severity of symptoms can vary considerably from one person to the next. Some people may experience debilitating, severe symptoms requiring time away from work or school, whereas other people may experience few or no symptoms at all. Due to this variability in presentation, and the fact that symptoms may overlap with other gastrointestinal illnesses (e.g. irritable bowel syndrome), the condition can be challenging to diagnose, resulting in delayed diagnosis, or having symptoms misdiagnosed as another illness.

Who is affected?

Coeliac disease is one of the most common chronic immune illnesses. It can affect people of any sex or ethnicity. Most cases are diagnosed between the ages of 40 and 60, however, diagnosis can occur at any age. Despite its prevalence, most cases go undiagnosed, and those that are identified are often preceded by a diagnostic delay of six to ten years or more. The condition has a strong genetic component, with most people sharing at least one of two common genetic variations associated with coeliac disease (i.e. the human leukocyte antigen variants HLA-DQ2 and/or HLA-DQ8). Although virtually all individuals diagnosed with coeliac disease possess one or both variants, they are nonetheless present in about half of the general population, and only about 3% of these people will develop the condition. Similarly, if you have close genetic ties to someone with coeliac disease (i.e. first-degree relative) you have about a 10% of developing the condition.