Racial disparities in relation to celiac disease in the United States
Who develops celiac disease (CD) and why? Three factors are involved: 1) a person must have the pre-disposing genes (~ 33% of the population have the genes, but only 1% develop CD); 2) A person must be consuming gluten; and 3) a person must experience some type of environmental triggering event or circumstance, which could include childhood antibiotic exposure, stressful events like surgery or pregnancy, make-up of the bacteria in the gut, and others factors (research is ongoing on factors which could be involved). The existence of any of the 3 factors necessary for development of celiac disease could theoretically vary and be influenced by race/ethnicity.
Also relevant is the fact that among individuals with celiac disease, many (likely at least half) remain undiagnosed. The likelihood of being diagnosed (access to medical care, lack of referral bias, and other factors) could also be influenced by race/ethnicity.
Based on the available data, the African American community in the U.S. needs more attention from the celiac community. This would include additional social support, improved medical attention, and additional research.
Following are summary points of some of the currently available relevant research
- Although in the past celiac disease was thought to affect predominantly Caucasian populations, a major systematic review published in 2018 which looked at data from 1991-2016 on 275,000 individuals with celiac disease (CD) concluded that CD is a major public health problem worldwide. (https://pubmed.ncbi.nlm.nih.gov/29551598/)
- There are differences in prevalence in different parts of the world and among different ethnic groups, but it is acknowledged by experts in the field that CD can and does exist among all groups. In this study prevalence of biopsy-confirmed celiac disease was found to be 0.5% in both Africa and North America.
- A study done in 2006 ( https://pubmed.ncbi.nlm.nih.gov/16642428/) which looked at 700 cases of CD (biopsy proven) found that although African-Americans made up 12% of the U.S. population, only 1% of the patients with celiac disease seen in this study group were African American.
- These authors noted:
- 1) The low rate of diagnosis among African Americans could be due to referral bias (less likelihood of being referred to a specialist), or to socio-economic factors that affect access to health care.
- These authors noted:
- Large scale study published in 2015. ( https://pubmed.ncbi.nlm.nih.gov/25577269/)
Included 14,000 participants. Looked for positive serology (tTG and EMA antibodies) only; biopsies not involved. In this study, it was found that prevalence of CD autoimmunity was 4 times higher among non-Hispanic whites (1.08%) than in non-Hispanic blacks (.22%).
While these results seem to indicate a lower likelihood of CD among African Americans, a commentary article (“Celiac Disease and the Forgotten 10%: the ‘Silent Minority’” https://pubmed.ncbi.nlm.nih.gov/25875755/) points out issues with this assumption:
- The tTG threshold levels could be lower in minorities, i.e. lower levels that were considered “normal” in this study could be indicative of CD in some minority individuals. Also, there are some cases of “sero-negative” CD, and these cases would have been missed. The “gold standard” of intestinal biopsy for diagnosing CD was not used.
- Under-diagnosis in a certain group can occur if it is assumed that there is lower prevalence – a sort of vicious cycle. If CD is still considered to be a Caucasian disease (or mostly Caucasian), then it will be under-diagnosed among other groups because it is not looked for.
With regard to racial disparities in CD generally, this author also points out:
- Research which found that among patients undergoing upper endoscopy for iron deficiency, anemia, diarrhea, and weight loss (all potential symptoms of CD), only 43% underwent duodenal biopsy, and that biopsy was less likely to be performed in black or Hispanic patients.
- Undiagnosed patients are self-prescribing a gluten-free diet (GFD), and are not always being highly compliant. (If an individual is not receiving adequate work-up for diagnosis, the patient may self-prescribe a GFD, and not be as concerned about being strictly GF since no official diagnosis has been made.)
- Author’s conclusion: “It behooves us to send a clear message: CD is common, potentially serious, and is present in Caucasians as well as non-Caucasians.”
Another study similar to the previous listing, also published in 2015. “Trends and Racial/Ethnic Disparities in Gluten-Sensitive Problems in the United States: Findings From the National Health and Nutrition Examination Surveys From 1988 to 2012.” (https://pubmed.ncbi.nlm.nih.gov/25665935)
- This research looked at racial disparities in the prevalence of celiac disease (CD) and in the number of people without CD avoiding gluten (“PWAG”). The prevalence of CD was found to be significantly higher among non-Hispanic whites than non-Hispanic blacks, whereas the prevalence of PWAG was significantly higher in blacks (1.2%) as compared with whites (0.7%) and Hispanics (0.5%).
- The points noted above made in the commentary article could similarly apply to these findings.
2012 study. “Gender and Racial Disparities in Duodenal Biopsy to Evaluate For Celiac Disease” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3445758/
Gastroenterologists use endoscopies to look inside the small intestine; based on what they see, they may decide to take tissue samples for biopsy, which is the basis for a CD diagnosis. Biopsies were less likely to be done on African Americans, so CD may have been missed.