The number of Americans diagnosed with celiac disease continued to rise over the past decade but leveled off in 2004, according to a new study.
Researchers analyzed data on a small but representative sample of people living in Olmsted County, Minnesota, and found that between the years 2000 and 2010, the number of new cases of celiac disease increased from about 11 people per 100,000 to about 17 people per 100,000.
"We're finding a lot more celiac disease," said Dr. Joseph Murray, the study's senior author from the Mayo Clinic in Rochester, Minnesota.
"Some of that is probably that we're better at detecting it, but the fact that we're finding it all the time shows that there are a number of new cases," he added.
In people with celiac disease - which includes about 1 percent of Americans, according to most estimates - the immune system reacts to gluten, a protein found in wheat, barley and rye. Eating foods with gluten damages the small intestine and keeps it from absorbing nutrients.
Classic symptoms of celiac are diarrhea and weight loss, according to Murray's report.
Previous studies have shown that the number of people living with the condition increased over time, but few studies looked at the number of new cases being diagnosed in recent years.
The researchers used medical records for people living in Olmsted County, which is home to the Mayo Clinic and two affiliated hospitals, and where the health of most of the population is tracked through research projects.
Over the entire decade starting in 2000, some 249 people were diagnosed with celiac disease in the county. People as young as one year old and as old as 85 received a diagnosis, and about 63 percent of the new cases were women.
Between 2000 and 2001, 26 people were diagnosed with celiac disease, which works out to about 11 per 100,000 people at the time. By 2002 to 2004, that number had climbed to 67 - or about 18 people per 100,000, and remained about the same from then on.
"This study shows not only did it go up, but it kind of plateaued in 2004 and it remained stable at that elevated level," Murray said.
He and his colleagues write in The American Journal of Gastroenterology that the increased incidence of celiac disease may be partly due to doctors knowing about the signs and symptoms of celiac disease and screening people at risk, but not entirely.
"Something has changed in our environment that's driving an increased incidence of celiac disease," Murray said.
In their report, Murray and his colleagues note that gastrointestinal infections have been linked to the development of celiac disease. So has high consumption of gluten-containing foods, like breads, bagels and pizza.
Dr. Alessio Fasano, director of the Center for Celiac Research at MassGeneral Hospital for Children in Boston, agreed that something in the environment seems to be triggering the various genetic and biological factors that drive celiac disease.
"If you lead the lifestyle of three or four generations ago, you don't see this epidemic. I do believe what we're witnessing with celiac disease is that we're changing the environment way too fast for our body to adapt to it," said Fasano, who was not involved with the study.
"When we're born we are like a marble block. What carves this into a wonderful sculpture is the environment," Fasano added.
Murray told Reuters Health that people should see their doctors if they have a family history of celiac disease, or are experiencing its most common symptoms - including iron deficiency, weakness, tiredness, diarrhea, passing gas and weight loss.