Methods: From January 1, 2009, through December 31, 2014, there were 22 278 persons 6 years or older who participated in NHANESs who underwent serologic testing for celiac disease for whom information about prior diagnosis of celiac disease and use of gluten-free diet was obtained by direct interview. Celiac disease was defined as having either double-positive serologic test results on IgA tissue transglutaminase and endomysial antibody or a reported diagnosis by a health care professional coupled with being on a gluten-free diet. People on a gluten-free diet without celiac disease were identified as those adherent to a gluten-free diet without serologic test results positive for celiac disease or a physician-given diagnosis. Trends in the prevalence of celiac disease and in adherence to a gluten-free diet among people without celiac disease were estimated in the total population, as well as by age, sex, and race. Appropriate published weights and a direct standardization method were used to estimate prevalence.
Researchers used NHANES to look at how many people who underwent serologic testing for celiac disease. They looked at how many of these people had a prior “diagnosis” of celiac disease and were on a gluten free diet.
They found 106 people who were confirmed as having a diagnosis of celiac disease and were adherent to a gluten free diet. They found 213 people who did not have celiac disease and were adherent to a gluten free diet.
These may sound like small numbers, but they represent 1.76 million and 2.7 million people in the US respectively. From 2009 to 2014, the prevalence of celiac disease was stable, but the prevalence of a gluten-free diet was not. It went from 0.52% in 2009-10 to 0.99% in 2011-12 to 1.69% in 2013-14. Of course, this is likely an underestimate of people eating a gluten-free diet, because some doing it without being entirely “adherent”, and many still go out of their way to avoid gluten for reasons that still elude me.