CD cases level off
Prevalence of celiac disease in the United States has stopped increasing while undiagnosed cases appear to have decreased. Meanwhile, the number of people following a gluten-free diet without a diagnosis has risen threefold since 2009 to an estimated 3.1 million Americans.
This study drew data from 22,277 participants in National Health and Nutrition Examination Surveys between 2009 and 2014. Individuals answered a questionnaire about celiac disease and the gluten-free diet and provided blood samples. Researchers at Mayo Clinic in Rochester, Minnesota, tested for elevated tissue transglutaminase (tTG) antibodies and endomysial antibodies (EMA). Celiac disease was considered confirmed in anyone who reported a clinical diagnosis or tested positive for both antibodies.
The proportion of people with celiac disease did not change significantly over the study period, holding steady at about 1 in 142 (0.7 percent), corresponding to approximately 2 million Americans. This contrasted with earlier studies showing a steady increase in the number of cases over recent decades.
During the same time period, the prevalence of undiagnosed celiac disease fell from 0.6 percent to 0.3 percent. The trend appeared particularly in non-Hispanic whites and adults. The decrease may reflect better awareness of the disease among the public and health care workers. However, popularity of the diet might also have influenced this data because antibody tests are less likely to detect celiac disease in people who avoid gluten.
The proportion of Americans who avoid gluten increased from 0.5 percent to 1.7 percent. The questionnaire did not ask participants why they made this choice. The authors note that the health and nutritional effects of the diet are unproven for people who do not have celiac disease or wheat allergy.
Persistent CD despite GF diet
Nearly one in five children with celiac disease had persistent damage to the gut despite following a gluten-free diet for at least a year in a study at two Boston hospitals. Blood tests for tTG conventionally used in follow-up failed to predict damage.
The study involved 103 children who had follow-up biopsies between one and 12 years after an initial biopsy to diagnose celiac disease. Nineteen percent of the patients still had tissue damage.
Blood tests detected elevated tTG in 43 percent of those with persistent damage and 32 percent of those with healing. Only 55 percent of patients with persistent damage reported feeling any symptoms, while a majority of healed patients also complained of symptoms possibly related to celiac disease.
Experts widely endorse tTG tests to monitor gluten-free adherence and recovery in patients with celiac disease. This study raises concern that the test, while accurate for initial diagnosis, is a poor indicator of healing. The authors argue an additional biopsy is the only way to confirm recovery.
This data set was small and relied on past medical histories, which is a statistically weak approach. While the findings raise an important concern, they will need confirmation by larger studies to recommend a change in health care practice.
The study also corroborates rising concern about a significant proportion of celiac disease patients who respond poorly to the gluten-free diet. Persistent damage to the gut increases risk for complications, such as lymphoma. This adds urgency to the search for alternative treatments for patients with unresponsive celiac disease.
Bone recovery on GF diet
The gluten-free diet improves impaired bone structure in women with celiac disease, according to Argentinian research.
Bone loss and fractures are common in untreated celiac disease patients. Dual-energy X-ray absorptiometry, which is typically used to detect loss of bone density, does not distinguish between the hard outer cortex and the inner spongy part of the bone. The team who performed this study had previously used an alternative, high-resolution peripheral quantitative computed tomography (HRpQCT), to look at microscopic structure of the porous tissue in premenopausal women. They detected significant deterioration in celiac disease patients.
This latest study investigated how the same bone structure changes as a result of treatment. It recruited 26 young women newly diagnosed with celiac disease. They underwent HRpQCT scans of the wrist and ankle when they were diagnosed and again after one year of treatment. Besides following a gluten-free diet, the patients took vitamin D supplements and were advised to consume adequate calcium through dairy products. The study compared the patients’ bone scores with those of a similar group of healthy women.
The microscopic structure of the spongy tissue improved significantly in all patients, especially in five women who achieved normal tTG tests after treatment. However, even after a year, the patients had not caught up with scores from the healthy control group. Researchers will continue to follow this study group and assess for recovery in the longer term. While vitamin D supplements probably accounted for some of the observed improvement, blood test scores showed an effective gluten-free diet had the most significant influence on bone recovery.
CD teens slightly smaller
Teenagers with celiac disease are smaller, but the difference is generally too minimal to raise health concerns, according to Israeli researchers. They made these findings from medical records of 2 million 16- and 17-year-olds reporting to military recruitment centers between 1988 and 2015.
The records identified 10,566 teens with celiac disease. Girls averaged one-quarter inch shorter than normal but showed no difference in body mass index (BMI). On the other hand, boys with celiac disease on average were leaner but matched the height of others their age, with a BMI of 21.2 compared to 21.7. The small differences suggest celiac disease diagnosed during childhood does not severely impair height and weight at maturity.
In this set of Israeli adolescents, the prevalence of diagnosed cases increased from one-tenth of a percent in 1988 to 1.1 percent in 2013-2015. Celiac disease was also significantly more common among teens born in Western countries compared to those from the former U.S.S.R., Asia and Africa. The same pattern appeared when comparing parents’ country of origin.
Did you know?
Cosmetics and personal care products containing gluten are safe for people with celiac disease if used with caution. Gluten must be eaten to cause the autoimmune reaction in contact with the gut lining. This applies even to people with dermatitis herpetiformis, a form of celiac disease involving an intense skin rash. A study that injected gluten into the skin of people with this condition failed to produce any reaction.
Sensitive people might prefer to avoid gluten in products like lipstick, lip gloss and hand lotion that they could ingest unintentionally. However, even with such a mistake, the tiny amounts consumed would not deliver the daily 10-milligram dose of gluten considered safe for people with celiac disease.
Skin products may contain problem ingredients for people with allergies such as wheat allergy. Several case studies involving individual patients suggest that hydrolyzed wheat protein in cosmetics can cause severe allergic reactions. Skin hypersensitivities are unrelated to celiac disease.
Van Waffle has a Bachelor of Science degree in biology and lives in Waterloo, Ontario, Canada. He is research editor for Gluten-Free Living. He blogs about nature, gardening and local food at vanwaffle.com.
 Choung RS, Unalp-Arida A, Ruhl CE, Brantner TL, Everhart JE and Murray JA, “Less hidden celiac disease but increased gluten avoidance without a diagnosis in the United States: findings from the National Health and Nutrition Examination Surveys from 2009 to 2014,” Mayo Clinic Proceedings, Jan 2017;92(1):30-38, doi: 10.1016/j.mayocp.2016.10.012.
 Leonard MM, Weir DC, DeGroote M, Mitchell PD, Singh P, Silvester JA, Leichtner AM and Fasano A, “Value of IgA tTG in predicting mucosal recovery in children with celiac disease on a gluten free diet,” Journal of Pediatric Gastroenterology and Nutrition, Nov 3 2016, doi: 10.1097/MPG.0000000000001460 [Epub ahead of print].
 Zanchetta MB, Longobardi V, Costa F, Longarini G, Mazure RM, Moreno ML, Vásquez H, Silveira F, Niveloni S, Smecuol E, de la Paz Temprano M, Massari F, Sugai E, González A, Mauriño EC, Bogado C, Zanchetta JR and Bai JC, “Impaired bone microarchitecture improves after one year on gluten-free diet: a prospective longitudinal HRpQCR study in women with celiac disease,” Journal of Bone and Mineral Research, Jan 2017;32(1):135-142, doi:10.1002/jmbr.2922.
 Assa A, Frenkel-Nir Y, Leibovici-Weissman Y, Tzur D, Afek A, Katz LH, Levi Z and Shamir R, “Anthropometic measures and prevalence trends in adolescents with coeliac disease: a population based study,” Archives of Disease in Childhood, 2016(0):1-6, doi:10.1136/archdischild-2016-311376.