By Amy Ratner, Medical and Science News Analyst

The celiac disease diagnosis rate in the United Kingdom increased to 30 percent in 2015, according to a new study, a one-quarter jump since the last study in 2011.

The study, sponsored by Coeliac UK, found that the number of people diagnosed had increased by 6 percent compared to the 2011 study that put the diagnosis rate at 24 percent.

Diagnois Plateau

However, when researchers from the University of Nottingham who did the new study looked at electronic health records, they also found that the rate of diagnosis had plateaued in 2012 after steadily climbing since 2005. Meanwhile, the rate at which patients are being tested for celiac disease fell after hitting a peak in 2011.

Researchers theorized that the plateau in diagnosis is most likely a function of the decline in testing. Testing may be down because of a lack of resources or because testing is more frequently being limited to high risk populations, the study says. Another possibility is that the threshold of clinically identifiable celiac disease has been reached, and a steady rate of the incidence of the disease has been obtained, the authors wrote.

In the United States, the celiac disease diagnosis rate is about 17 percent, though estimates vary, and some research has shown that people are being diagnosed more frequently. A 2016 study at the Mayo Clinic found a “considerable decrease” in hidden celiac disease from 2009 to 2014 among participants in the National Health and Nutrition Examination Surveys (NHANES).

Research has shown that celiac disease affects about one percent of the population in both the United States and United Kingdom, but most are undiagnosed or misdiagnosed.

Despite the increase in diagnosis in the UK, about a half million people remain undiagnosed, according to Coeliac UK, an advocacy group for people who have medical conditions that require them to follow the gluten-free diet.

Misdiagnosis

Their study also found that one in four adults over the age of 18 who are diagnosed with celiac disease had previously been misdiagnosed with irritable bowel syndrome, a number that has not budged since 2013.

“It’s fantastic that the research shows that around 45,000 people were diagnosed between 2011 and 2015,” said Sarah Sleet, Coeliac UK chief executive. “But with half a million people in the UK still without a diagnosis, we’ve got a long way to go.”

The continued misdiagnosis and the slow-down in testing suggest the national healthcare system is “failing to address the mountain of underdiagnoses,” Sleet said, noting that celiac disease research shows some symptoms of the disease can’t be reversed if it’s not detected early..

Coeliac UK plans to launch a campaign in 2019 to encourage physicians to consider celiac disease as the cause of patients’ symptoms, particularly among those who have been diagnosed with IBS. The group will also encourage doctors to advise patients not to initiate a gluten-free diet before being tested for celiac disease, something that occurs often.

An abstract, or summary, of the study was presented at the Coeliac UK Research Conference and published in Gut, the journal of the British Society of Gastroenterology.

You can read more about the celiac disease diagnosis rate study here and here.