Background and aims: Despite similar genetic risk for celiac disease (CeD), population prevalence of CeD is lower in southern part of India compared to the northern part possibly due to low dietary gluten ingestion. Their emigration to northern India may increase their risk of developing CeD. We therefore investigated the prevalence of CeD in second-generation south-Indians whose parents have migrated to northern part of India.
Subjects and Methods: In this cross-sectional epidemiological study, multiple regions of New Delhi were systematically assessed to recruit second-generation immigrant South Indians. The recruited participants provided details regarding their demographics and dietary practices including gluten exposure in their early life using validated questionnaires. They were screened for CeD using IgA anti tissue transglutaminase antibody (IgA anti-tTG Ab) ELISA kits from two different manufacturers. The prevalence of CeD was defined a priori by all those having anti-tTG Ab positive using two test kits. HLA DQA1/DQB1 haplotype alleles were assessed in seropositive individuals.
Results: We screened 21,810 households in 15 sub-districts of Delhi and recruited 1870 eligible second-generation south-Indians (50.2% males, mean age 33.05+7.76 years). The seroprevalence of CeD using two IgA anti-tTG tests was 1.23% (23/1870; 95%CI:0.73-1.73%), closely mirroring native north Indians [1.22% (95% CI:0.95-1.50); p=1.0], but significantly higher than native south Indians [0.13% (95%CI:0.06-0.21%); p<0.001] reported in our previous study. There was a trend towards higher gluten intake score in the first year of life and risk of seropositivity for CeD (22 [14-31] vs 30.50 [22.50-34.50]; p = 0.065). Classic HLA D2/DQ8 haplotype alleles were present in 9/23 (39.1%) people with CeD seropositivity.
Conclusions: The seroprevalence of CeD in second-generation south-Indian migrants residing in north-India matches native north Indians and is much higher than native South Indians. Genetically susceptible individuals residing in low gluten eating region may develop CeD on migration to high-gluten eating regions.