Celiac.com 11/16/2011 - Researchers still don't know very much about the natural history of celiac disease and whether it may increase or decrease in prevalence over time.
A research team recently set out to determine whether loss of tolerance to gluten may develop at any age, to investigate possible long-term changes in celiac disease prevalence, and to better understand other celiac-related issues.
The team analyzed 3,511 subjects with matched samples from 1974 (CLUE I) and 1989 (CLUE II). For their study, the team chose and followed 3,511 subjects from two large groups of more than 20,000 Americans aged 13-80 in 1974 and 1989. To see if there was an observable change in rates of celiac disease among the subjects over time, they took blood samples in 1974 and again 15 years later in 1989.
They gave follow-up questionnaires to the subjects every 2 or 3 years from 1996 to 2007 to compile health status updates on the participants. Researchers conducted antibody testing on the blood samples. These tests showed just seven subjects with antibodies specific to celiac disease in 1974, for a disease rate of 1 in 501 subjects.
By 1989, nine more samples showed markers for celiac disease, for a rate of 1 in 219 subjects; more than double the 1974 rate.
The study also looked at another 804 samples from subjects who died after the 1974 survey and found two more likely cases of celiac disease. To counter any selection bias regarding survival, the team also assessed 840 CLUE I participants who died after the 1974 survey.
Since the individuals who provided the original samples did not undergo biopsy, and thus cases of celiac disease remain unconfirmed. Also, the study sample was not nationally representative by age, race, and gender, which may also have impacted the findings.
The researchers state that this increase may be partly due to increased awareness of the disease. Still, many cases continue to go undiagnosed. In fact, only 11% of the study subjects who had celiac disease-specific antibodies in both the 1974 and 1989 surveys had actually been clinically diagnosed with the disease by their doctors.
Also, the study found two subjects in their 50s who tested negative in 1974, but positive in 1989, when in their 60s. This indicates that the disease can strike at any age. This finding is supported by a study from Finland that found that celiac disease was more common among the elderly.