July 1, 2009 -- Celiac
disease -- the digestive disorder treated by banning wheat and other grains
containing gluten from the diet -- is four times more common
in the U.S. today than it was 50 years ago, a study shows.
The study by Mayo Clinic researchers also linked undiagnosed and untreated
celiac disease with an increased risk for earlier death.
Even with increased awareness about gluten-free diets
and celiac, the disease remains underdiagnosed, experts say.
"We believe that only about 5% of people with celiac disease know they have
it," University of Chicago Celiac Disease Center Director Stefano Guandalini,
MD, tells WebMD. "Many of these people have no symptoms, but many do have
symptoms that are not recognized for what they are."
Joseph A. Murray, MD, lead author of the study, says in a news release that
celiac disease now affects about one in 100 people in the U.S.
Celiac disease is a digestive disorder in both children and adults. When
people with celiac disease eat foods that contain gluten, an inflammatory
reaction occurs that can damage the small intestine and inhibit the absorption
Symptoms of celiac disease can include diarrhea, abdominal discomfort, weight
loss, anemia, unexplained infertility, premature osteoporosis, loss of teeth, and
other health issues.
Gluten is present in all types of wheat, rye, and barley. Completely
eliminating these foods from the diet for life is the only known treatment.
In the Mayo Clinic study, stored blood samples collected from healthy male
army recruits between 1948 and 1954 were tested for the presence of a
The Mayo researchers also tested blood samples collected just a few years
ago from men whose ages were either similar to the recruits at the time the
samples were taken or at the time of the study.
They found that:
The samples from the contemporary group of young people were 4.5 times more
likely to have the celiac antibody than the samples drawn in the 1950s.
The contemporary samples taken from older men whose ages matched the
current ages of the recruits were four times as likely to have the
During 45 years of follow-up, undiagnosed celiac disease was associated
with a fourfold increased risk of death.
In a 2003 study, Murray and colleagues found that celiac disease was being
diagnosed at a rate that was nine times higher than just a decade before.
One aim of the new study was to find out if this represented a real increase
in incidence or simply better awareness of the disease and better ways of
"Celiac disease is unusual, but it's no longer rare," Murray says.
"Something has changed in our environment to make it much more common."
Celiac Disease and the Hygiene Hypothesis
One theory is that celiac disease is on the rise because we are exposed to
fewer germs than in the past, says Murray.
The so-called "hygiene hypothesis" suggests that this diminished exposure
has increased our susceptibility to certain diseases.
Murray tells WebMD that changes in the way wheat is grown and processed may
also play a role.
"These are just theories," he says. "We really can't say what the
environmental influences are."
"The good news about celiac, which makes it unique among autoimmune
disorders, is that it is completely reversible once you begin the gluten-free
diet," Guandalini says. "The majority of patients have very rapid responses,