Americans from the Punjab region of India had the highest prevalence of celiac disease in a national cross-sectional study of duodenal mucosal biopsies according to a study reported in the August issue of Clinical Gastroenterology and Hepatology.
In contrast, persons of South Asian, East Asian, and Hispanic descent are significantly less likely to receive a biopsy-based diagnosis of celiac disease than were other Americans, Anna Krigel, MD, at Columbia University, New York, reported with her associates. The prevalence of celiac disease among Jewish and Middle Eastern individuals resembled that of other Americans and did not differ by sex, the researchers added. “These findings may have clinical relevance to gastroenterologists across the United States and may aid in their diagnostic practices.”
Dr. Krigel and her associates analyzed a national laboratory pathology registry of 454,885 patients who underwent esophagogastroduodenoscopy with duodenal biopsy between January 2008 and April 2015. Mucosal biopsy specimens were analyzed at three laboratories by histopathologists who had completed fellowships in gastrointestinal pathology. Patients were categorized based on their first and last names as North Indian, South Indian, East Asian, Hispanic, Middle Eastern, Jewish, or as “other Americans,” using a published algorithm. The researchers further validated this algorithm by adjusting it against a list of individuals of known ethnicities until its specificity reached 95%. Two-thirds of patients in the cohort were female, and the median age was 53 years (Clin Gastroenterol Hepatol. 2016 May 31. doi: 10.1016/j.cgh.2016.04.032).
Overall, 7,928 patients (1.7%) had duodenal villous atrophy indicative of disease, including 2% of North Indians, 1.8% of Jewish individuals, 1.8% of other Americans, 1.5% of Middle Easterners, 1.1% of Hispanics, and 0.15% of East Asians, said the investigators. Thus, Jewish persons and Middle Eastern persons had a prevalence of celiac disease similar to that of other Americans. Prevalence also was similar among Ashkenazi and Sephardic Jews. In contrast, none of the 177 South Indians in the study were diagnosed with celiac disease, and both East Asians and Hispanics were significantly less likely to be receive a diagnosis than other Americans, with odds ratios of 0.08 (95% confidence interval, 0.04-0.17) and 0.58 (0.52-0.64), respectively, and P values less than .0001.
Importantly, celiac disease was significantly more common among patients from the Punjab region of India (3.1%) than among other North Indians (1.5%; P = .02). Past studies of celiac disease in India reported similar prevalences of compatible human leukocyte antigen (HLA) haplotypes as in Western countries, without notable regional trends within India, the researchers noted. Substantial regional variations in wheat consumption in India are more likely to explain their findings and patterns of case reports in past studies, they added.
Because the registry lacked serology data, patients diagnosed with celiac disease could have actually had tropical sprue or sprue-like enteropathy due to olmesartan, the researchers acknowledged. “In particular, multiple studies have shown that tropical sprue is still the most common cause of malabsorption syndrome in India, whereas celiac disease is emerging as a more important cause of malabsorption than previously thought,” they said. “However, such cases of tropical sprue and sprue-like enteropathy due to olmesartan are far less common than celiac disease in the United States.” The study also did not account for patients whose celiac disease only was diagnosed by serology and clinical symptoms, and the algorithm probably assigned some individuals who were Hispanic to other ethnicities, because only 7% of the cohort was classified as Hispanic, compared with about 16% of Americans in the 2010 U.S. Census, they noted. But ethnic misclassification was unlikely to have differed by celiac disease status, they said.
The National Institutes of Health partially supported the work. The authors had no disclosures.