Hot off the press – the Canadian Medical Association Journal has published a comprehensive and up to date overview on the diagnosis and management of celiac disease based on the most current evidence. Here are the key takeaways from that review!
Celiac disease, an immune-mediated conditions triggered by the protein gluten, has become the most common autoimmune disorder of the gastrointestinal tract worldwide. Despite this, it remains significantly undiagnosed due to the variability in symptoms and high level of clinical awareness needed to recognize it.
A 2018 systematic review and meta-analysis found that both the number of new cases and the overall number of people with celiac disease have increased over the past two decades. Globally, 1.4% of people test positive on blood tests for celiac disease antibodies, and 0.7% have confirmed findings on small intestine biopsies.
In Alberta, Canada, a large population study showed that cases rose from 31.5 per 100 000 person-years in 2015 to 40.3 per 100-000 persons-years in 2020, with an annual average percent change of 6.2%. Notably, this increase occurred without changes to the rate of tTG-IgA testing.
The reasons behind rising rates aren’t fully known. Possible contributing factors include viral infections, early antibiotic exposure, and higher amounts of gluten introduced in childhood.
Consistent with earlier studies, celiac disease is more common in:
Genetic also play a key role. People with HLA-DQ2, HLA-DQ7, or HLA-DQ8 genes are at increased risk, and first-degree relatives have the highest lifetime risk, with rates between 11% to 15%.
Several autoimmune conditions, such as type 1 diabetes, Hashimoto thyroiditis, autoimmune hepatitis, primary biliary cholangitis, and Sjogren syndrome, also carry increased risk (2% to 7%). People with inflammatory bowel disease may have a higher risk as well, and this relationship appears to be bidirectional.
Celiac disease is also more common in certain genetic and chromosomal conditions, including:
Although several innovations are emerging in the area of diagnosing celiac disease, current clinical guidelines remain the recommended practice.
For people aged 2 years and older with suspected celiac disease, the first step is a tTG-IgA blood test, which has a sensitivity and specificity of 90% to 95%. A positive test suggests celiac disease but do not always confirm it, as false positives and false negatives can occur in up to 10% of cases.
Eating enough gluten in the diet is essential for accurate testing. For people who may have reduced intake or have eliminated gluten from their diet, this may lead to false-negative results. Some individuals, specifically those with selective IgA deficiency, may also test negative even if they have celiac disease. Fortunately to help prevent missed diagnoses, many Canadian laboratories automatically check total IgA levels before measuring tTG-IgA.
If the blood test is positive and gluten intake is adequate, the next step is tissue examination through an upper endoscopy and biopsy of the small intestine.
The role of intestinal biopsies has been discussed extensively in the medical community. Current European guidelines for children, and more recently adults, suggest that biopsies may not be needed if:
Skipping biopsies can reduce the need for invasive procedures, lower costs, and speed up diagnosis. However, concerns remain about misdiagnosis and unnecessary dietary restrictions, which can carry financial and social burdens.
Currently, the only recommended treatment is lifelong adherence to a gluten-free diet. Working with a registered dietitian at diagnosis and during follow-up is essential to ensure nutritional adequacy.
Following a gluten-free diet can be challenging with 42% to 91% of individuals reporting adherence. Cost and access to gluten-free products are major barriers, with one Canadian study finding products to be 4 to 5 times more expensive than gluten-containing counterparts. Many available products are also of lower nutritional quality, relying heavily on rice and corn.
Food labelling requirements ensure that products labeled “gluten-free” contain less than 20ppm of gluten, a level considered safe. However, Canada does not currently require gluten labelling for medications.
About 40% of patients with celiac disease experience ongoing symptoms, such as diarrhea, constipation, bloating, abdominal pain, nausea, or vomiting, despite following a gluten-free diet for at least 12 months. This is known as non-responsive celiac disease.
The most common cause is accidental gluten exposure, so careful dietary review is the first step. Other possible diagnoses include lactose or fructose intolerance, irritable bowel syndrome, bacterial overgrowth in the small intestine, exocrine pancreatic insufficiency and microscopic colitis. Working closely with a clinician is essential for proper evaluation.
To protect long-term health, current guidelines recommend:
These vaccines are especially important for people with autoimmune conditions like celiac disease, as they help reduce the risk of severe infection and related complications.
These vaccines are especially important for people with autoimmune conditions like celiac disease, as they help reduce the risk of severe infection and related complications.
People with celiac disease require regular follow-up and ongoing monitoring, as some may continue to have abnormal blood tests, persistent symptoms, or incomplete healing of the small intestine. These issues can increase the risk of complications over time.
A small proportion of individuals develop refractory celiac disease, a rare condition in which symptoms of malabsorption and damage to the intestinal lining continue despite strict adherence to a gluten-free diet for more than one year.
Although tTG-IgA blood tests are not perfect indicators of disease activity, current pediatric and adult guidelines recommend monitoring these levels until they become undetectable. For more people, tTG-IgA levels normalize within 12 months of following a strict gluten-free diet. However, for those with very high levels at diagnosis, normalization may take 2 to 3 years. Persistent or rising tTG-IgA levels may indicate ongoing gluten exposure, while undetectable levels do not necessarily confirm perfect adherence or full intestinal healing.
Routine repeat biopsies of the small intestine are generally not needed until enough time has passed for healing to occur, typically around two years on a gluten-free diet.
Bone health is another important aspects of long-term care. One suggested approach is to repeat a DXA bone scan after 2-3 years for people with osteopenia and after 1 year for those. With osteoporosis. People with osteopenia should also ensure adequate daily intake of:
Overall, the Canadian Medical Association Journal review reinforces with timely diagnosis, proper monitoring, and dietary support, people with celiac disease can live healthy lives. Continued awareness and evidence-based care will be key to ensuring fewer cases go undiagnosed and more individuals receive the care they need.
References
News, hot topics, tips, education & more.
