title: Less Hidden Celiac Disease But Increased Gluten Avoidance Without a Diagnosis in the United States: Findings From the National Health and Nutrition Examination Surveys From 2009 to 2014.
abstract: OBJECTIVE
  To investigate the trends in the prevalence of diagnosed celiac disease (CD), undiagnosed CD, and people without celiac disease avoiding gluten (PWAG) in the civilian noninstitutionalized US population from 2009 to 2014.
  
  
  METHODS
  We studied the occurrence of CD and PWAG in the 2009 to 2014 National Health and Nutrition Examination Surveys. The serum of all participants aged 6 years or older from the National Health and Nutrition Examination Surveys from 2009 to 2014 was tested for CD serology at Mayo Clinic. Participants were interviewed for a diagnosis of CD and the use of a gluten-free diet (GFD). The design effects of the survey and sample weights were incorporated in all statistical analyses.
  
  
  RESULTS
  In the US general population, the prevalence of CD did not change significantly from 0.7% (95% CI, 0.6%-0.8%) in 2009 to 2010 to 0.8% (95% CI, 0.4%-1.2%) in 2011 to 2012 to 0.7% (95% CI, 0.3%-1.0%) in 2013 to 2014. However, the prevalence of undiagnosed CD decreased from 0.6% in 2009 to 2010 to 0.3% in 2013 to 2014. In contrast, the prevalence of PWAG increased significantly from 0.5% (95% CI, 0.2%-0.9%) in 2009 to 2010 to 1.0% (95% CI, 0.6%-1.4%) in 2011 to 2012 to 1.7% (95% CI, 1.1%-2.4%) in 2013 to 2014 (P=.005 for trend).
  
  
  CONCLUSIONS
  Although the overall prevalence of CD remained stable from 2009 to 2014, the proportion of individuals with CD that is hidden considerably decreased. Moreover, the proportion of individuals without CD but following a GFD increased markedly from 2009 to 2014. Long-term health consequences of a GFD warrant further investigation.
authors.affiliation: Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN.
authors.forename: Rok Seon
authors.initials: RS
authors.lastname: Choung
authors.affiliation: Department of Health and Human Services, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD.
authors.forename: Aynur
authors.initials: A
authors.lastname: Unalp-Arida
authors.affiliation: Social & Scientific Systems, Inc., Silver Spring, MD.
authors.forename: Constance E
authors.initials: CE
authors.lastname: Ruhl
authors.affiliation: Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN.
authors.forename: Tricia L
authors.initials: TL
authors.lastname: Brantner
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD.
authors.forename: James E
authors.initials: JE
authors.lastname: Everhart
authors.affiliation: Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN. Electronic address: murray.joseph@mayo.edu.
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Murray