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.

Patients and 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).

Conclusion: 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.

Figure 1

From an eligible population of 25,547 participants aged 6 years or older in the NHANES 2009–2014, 22,277 had serologic samples tested for CD. Of 7,798 participants in NHANES 2009–2010, 35 had a diagnosis of CD and 49 were PWAG. Similarly, 33 had CD and 69 had PWAG in NHANES 2011–2012 (n=6,903), while 41 had CD and 95 had PWAG out of 7,576 participants in NHANES 2013–2014. CD, celiac disease; PWAG, people without CD avoiding gluten; NHANES, National Health and Nutrition Examination Survey.

Figure 2

Trends in total and undiagnosed CD prevalence between 2009 and 2014. While the prevalence of total CD remained stable in this period, the prevalence of undiagnosed CD decreased in the last 2-year cycle. Interestingly, the prevalence of diagnosed CD increased dramatically in the last 2-year cycle. Total CD included participants with either serologically diagnosed CD or a reported clinical diagnosis of CD. CD, celiac disease; NHANES, National Health and Nutrition Examination Survey; *, % (95% confidence interval).

Figure 3

Trends in GFD and PWAG prevalence between 2009 and 2014. The prevalence of total GFD and PWAG significantly increased between NHANES 2009 and 2014. Total GFD included participants who positively responded to following a GFD regardless of CD status. CD, celiac disease; GFD, gluten-free diet; PWAG, people without CD avoiding gluten; NHANES, National Health and Nutrition Examination Survey; *, % (95% confidence interval)

Figure 4

Trends and relative proportions of CD and PWAG among gluten-related occurrences (GRO) between NHANES 2009 and 2014. The prevalence of GRO increased from NHANES 2009–2010 to 2013–2014. This increasing trend in GRO prevalence was predominantly due to increases in PWAG. However, the proportion of undiagnosed CD decreased from 51% in NHANES 2009–2010 to 12% in NHANES 2013–2014. CD, celiac disease; PWAG, people without CD avoiding gluten; NHANES, National Health and Nutrition Examination Survey; *, % (95% confidence interval)