Approximately 1% of American Caucasians may now have celiac disease, according to a major epidemiologic survey by researchers at the Mayo Clinic.
Once thought to be rare and largely marginalized by mainstream medicine, conditions like celiac disease and gluten intolerance are proving to be much more common—and serious—than previously thought.
“It’s kind of ironic: we estimate that 1.8 million Americans have celiac disease, but most don’t know, and they’re not on treatment although they should be,” explained Dr. Joseph Murray, MD, professor of medicine, and a consultant in gastroenterology and immunology at the Mayo Clinic, in Rochester, Minnesota.
“On the other hand, 1.6 million are on the gluten-free diet, and most don’t have a diagnosis, so we don’t know if they need to be on the diet,” added Dr. Murray, one of the co-authors of the study, published earlier this fall in American Journal of Gastroenterology.
Celiac disease is a condition that affects the small intestine, and is the result of an immune reaction to gluten. The gut gets inflamed, and the individual may get diarrhea, bloating, or weight loss. “But celiac can also affect the skin, the nervous system, hormones, the lungs, or virtually any part of the body,” Dr. Murray said.
Until fairly recently, conventional medical wisdom held that celiac disease was extremely rare, and physicians often dismissed patient complaints as “psychosomatic.” Clearly, things have changed.
Four-Fold Higher Mortality
In the Mayo Clinic study, researchers examined blood samples from 7,798 participants, aged 6 years and older, in the National Health and Nutrition Examination Survey (NHANES) for 2009 and 2010. Participants were also asked two questions: whether they were on a gluten-free diet, and whether they had been given a diagnosis of celiac disease by a health care professional.
Of the 7,798 participants, 34 (0.4%) had definitively positive blood tests for celiac, or 34 patients, and another 15 (0.2%) were weakly positive in 0.2%. Median age of the patients was 38, and half were female, 44% were non-Hispanic white, 32% were Hispanic, and 18% were non-Hispanic black. On the basis of 35 cases that were either serologically diagnosed with celiac disease or a reported clinical diagnosis, the prevalence of celiac disease in the U.S. was 0.71%, but among non-Hispanic whites, the prevalence was 1.1%, according to the article.
In an earlier study, Murray and colleagues examined stored blood samples from 9,133 young male recruits between 1948 and 1954 from an Air Force base in Wyoming, and tested them for markers for celiac disease. In addition, they gathered 45-year follow-up data for those with and without markers for celiac disease, and compared all-cause mortality for the two groups, according to the article, ‘Increased Prevalence and Mortality in Undiagnosed Celiac Disease,’ which was published in the July 2009 issue of Gastroenterology.
The Mayo team determined that of the cohort, 0.2% (or 14 participants) had undiagnosed celiac disease.
Rising Prevalence in Elders
On follow-up, those with undiagnosed celiac disease were 3.9 times more likely to have died of any cause than those who did not have the condition. Additionally, during the 2009 study, researchers examined a contemporary sample of persons with a similar age and found undiagnosed celiac disease in 0.9% of that cohort, or 4.5 times as many participants as in the 1964 study.
“We’re also seeing celiac start for the first time in the elderly,” said Dr. Murray, though he hesitated to give reasons for this phenomenon.
“Maybe it’s something about contemporary food preparation, or something about hygiene,” he said. Alternatively, researchers have speculated that the rise could be attributed to greater consumption of processed wheat products like pastas and baked goods than in decades past, or it could be due to new forms of wheat, which were cross-bred by scientists in the 1950s to make hardier, shorter and better-growing plants.
Whatever the cause, the results called for greater surveillance. “We’re obviously not doing a great job from the medical perspective,” said Dr. Murray. He suggested that patients should get tested for celiac disease before switching to a gluten-free diet, “Going on the diet may delay diagnosis, and may lead to slowed growth in children.”
He advised caution with genetic tests, suggesting that they should only be used under a physician’s direction, because approximately 30% of the population has the genes for celiac disease, but most people never develop symptoms.
The subject of food sensitivities, their role in autoimmune disorders and new advances in testing methodology will be the focus of a special luncheon lecture by immunology pioneer Aristo Vojdani, PhD, at HPC’s upcoming Heal Thy Practice conference, Nov. 9-11 in Long Beach, CA.