For the United States population, the number that's most often quoted is that nearly 1 out of every 100 people has celiac disease. This statistic comes from a large study, which makes it more reliable. On the other hand, subjects in the study were predominantly Caucasian. The prevalence of celiac disease in other ethnic groups may not be the same as in Caucasians, so the "1 in 100" number may not be exactly right -- but it's the best estimate we have so far.
Researchers believe that more than 2 million people in the United States have celiac disease but don’t know it.
Among people who have a close relative with celiac disease, the prevalence is known to be even higher. If you are a first-degree relative -- parent, child, brother or sister -- of a person with celiac disease, you have a 1 in 22 chance of developing the disease in your lifetime. If you are a second-degree relative -- aunt, uncle, niece, nephew, grandparent, grandchild or half-sibling -- your risk is 1 in 39.
Fasano A et al. Prevalence of celiac disease in at-risk and not-at-risk groups in the United States: a large multicenter study. Archives of Internal Medicine 2003;163:286-92.
National Institutes of Health. Accessed: February 2, 2009. http://digestive.niddk.nih.gov/ddiseases/pubs/celiac/index.htm#common
University of Chicago Celiac Disease Center. Accessed: February 2, 2009. http://www.uchospitals.edu/specialties/celiac/
University of Maryland Center for Celiac Research. Accessed; February 2, 2009. http://www.celiaccenter.org/celiac/faq.asp#common
Wm. K. Warren Medical Research Center for Celiac Disease Research. Accessed: February 2, 2009. http://celiaccenter.ucsd.edu/learn_more.shtml