Celiac disease is an autoimmune disorder triggered by gluten, a protein in wheat, barley, rye and spelt. Currently, the only treatment available is the adoption of a lifelong gluten free diet, which is made particularly challenging due to the ubiquity of wheat in western diets.
It has been suggested that celiac disease is on the rise due to increased diagnosis; about 40,000 to 60,000 people in the US have been diagnosed with the disease, although the federal government estimates that there could be as many as 3m who are undiagnosed – or just under one percent of the population. But this latest study, published this month in the journal Gastroenterology, suggests that increased awareness and better diagnosis might not explain rising numbers of celiac disease sufferers.
Researchers examined 9,133 frozen blood samples taken from US Air Force recruits between 1948 and 1954 for the antibody that people with celiac disease produce in reaction to gluten, and found that only about one in seven hundred tested positive, or 0.2 percent.
They then compared this to rates of celiac disease among 12,768 people who either had similar years of birth (i.e. were born around 1930) or who were of a similar age to the original donors at the time of sampling (i.e. young adults today). The rates of celiac disease were 0.8 percent and 0.9 percent respectively, or a 4 to 4.5-fold increase.
“Celiac disease has become much more common in the last 50 years, and we don't know why,” said Dr Joseph Murray, the Mayo Clinic gastroenterologist who led the study. “…Obviously human genes haven’t changed, but something has changed in our environment to make this disease more common.”
The researchers also noted an increased mortality rate for those with undiagnosed celiac disease, which they said could raise questions about public health policy.
“By following up the people who were positive, it looks as if they are almost four times as likely to have died within the thirty to forty years of follow-up as people who were negative for celiac disease,” said Murray.
“Until recently, the standard approach to finding celiac disease has been to wait for people to complain of symptoms and to come to the doctor for investigation. This study suggests that we may need to consider looking for celiac disease in the general population, more like we do in testing for cholesterol or blood pressure.”
Murray emphasized that it is important to get a positive test result for celiac disease before embarking on a gluten free diet, which should be devised with the help of a qualified dietitian.
Meanwhile, the food industry has been responding to growing demand for gluten-free foods, and market research organization Packaged Facts estimates that sales of gluten-free products will reach $2.6bn by 2012.
In a recent report, it said that the gluten-free market has grown at an average annual rate of 28 percent since 2004, when it was valued at $580m, to reach $1.56bn last year.
Volume 137, Issue 1, Pages 88-93 (July 2009)
Increased Prevalence and Mortality in Undiagnosed Celiac Disease
Authors: Alberto Rubio–Tapia, Robert A. Kyle, Edward L. Kaplan, Dwight R. Johnson, William Page, Frederick Erdtmann, Tricia L. Brantner, W. Ray Kim, Tara K. Phelps, Brian D. Lahr, Alan R. Zinsmeister, L. Joseph Melton, Joseph A. Murray.