If you think you’re too old to develop new dietary restrictions, think again. A long-term study from the University of Maryland recently concluded that Celiac disease, an autoimmune disease that currently affects 1 in 133 Americans, is characterized by intolerance to gluten, a protein found in wheat, rye, and barley, which are commonly found in many processed foods and even some medications. According to experts, the prevalence of celiac disease has increased by 5 times in the last 30 years among Americans.
The study followed 3,511 randomly chosen subjects from two large cohorts of over 20,000 Americans aged 13-80 in 1974 and 1989. The researchers wanted to determine if there was an observed change in prevalence of celiac disease among the subjects over time. Blood samples were drawn in 1974 and again 15 years later in 1989. Follow-up questionnaires were given every 2 or 3 years from 1996 to 2007 to obtain health status updates on the participants.
Using antibody testing on the blood samples, the research team found just seven subjects with antibodies specific to celiac disease in 1974, equating to a disease prevalence of 1 in 501 subjects. Nine more subjects showed markers for celiac disease (CD) in 1989, representing a disease prevalence of 1 in 219 subjects – or, double the rate from 1974. The study also analyzed an additional 804 samples from participants who were deceased after the 1974 survey and found two more with indications of the disease. While the blood tests used in this study are a strongly suggestive of the presence of celiac disease, it should be noted that only intestinal biopsy–which was not conducted in this study– can definitively confirm the presence of the disease. Furthermore, the study sample was not nationally representative by age, race, and gender, which may also have impacted the findings.
The researchers point out that while part of this increase may be due to increased awareness of the disease, many cases continue to go undiagnosed. In fact, only 11% of the study subjects who had CD-specific antibodies in both the 1974 and 1989 surveys had actually been clinically diagnosed with the disease by their doctors. Interestingly, one of the two cases with identified CD markers among the 840 deceased subjects was found to have died of intestinal cancer, a co-morbidity strongly linked to celiac disease.
The rising prevalence in celiac disease is attributed mostly to increased diagnosis in children, especially those with risk factors such as a family history of CD or other autoimmune diseases, including type-1 diabetes. However, the study, which found two subjects in their 50s who tested negative in 1974 and positive in 1989 when they were in their 60s, suggests that the disease can strike at any age.
In support of this finding, a recent study from Finland similarly found that celiac disease was actually more common among the elderly. Possible explanations for late acquisition include the quantity of gluten consumed as diets change over time and infections of the intestines. Though experts hope to use this information to pinpoint prevention methods, the researchers note that further studies will be necessary to more fully understand celiac and other autoimmune diseases.