Why Does Ireland Have So Many Coeliacs?

Ireland has a curious distinction when it comes to coeliac disease: it has one of the highest rates recorded in Europe. Around one person in every 100 in Ireland is thought to have coeliac disease, although the true figure may be higher because many people have the condition without knowing it.
So why Ireland?
The biggest clue is in their genes. Coeliac disease is strongly linked to particular genes called HLA-DQ2 and HLA-DQ8. These genes help the immune system recognise substances in the body, but in people with coeliac disease they can mistakenly identify gluten as a threat. More than 90% of people with coeliac disease carry the HLA-DQ2.5 variant.
Everyone still awake…?
These genetic variants are particularly common among people of Northern European ancestry, including the Irish. But having the genes does not mean you will definitely develop coeliac disease. In fact, many people carry them and happily eat bread without their immune system declaring war on their toast.
Diet may also play a part. Ireland has traditionally had a diet containing plenty of wheat and other gluten-containing foods. Research suggests that the amount of gluten-containing grain available in a population may influence coeliac disease rates, although the relationship is complicated and is certainly not the whole story.
There may also be environmental factors, including infections and differences in early-life exposure to gluten, but scientists still don’t have a complete answer.
So Ireland’s high rate of coeliac disease appears to be the result of genetics meeting environment, with a large helping of unanswered questions on the side.