METHODS: Thirty-four polymorphisms in 26 genes were typed by mass spectrometry in 422 patients undergoing endoscopy (162 Chinese, 113 Indian and 87 Malay controls and 60 Chinese GC cases). Patients were assessed for evidence of H. pylori infection. Odds ratios (OR) and confidence intervals (CI) were obtained using logistic regression models.
RESULT: The prevalence of 16 polymorphisms varied significantly among the ethnicities. In the Chinese subgroup, nominally significant associations were shown between (i) EBBR2+1963G (rs1801200) and H. pylori infection (per-allele OR: 0.48, 95% CI 0.23, 0.98, P = 0.04), (ii) PTGS2-1195G (rs689466) and an increased risk of GC on adjusting for H. pylori status (OR: 1.53, 95% CI 0.99, 2.37, P = 0.05), and (iii) IL1B-1473C (rs1143623) and a decreased risk of GC (OR: 0.64, 95% CI 0.41, 0.99, P = 0.05). Borderline significant associations were seen between IL2-330G (rs2069762) (OR 1.45, 95% CI 0.95, 2.15, P = 0.06) and IL13-1111T (rs1800925) (OR 0.65, 95% CI 0.42, 1.01, P = 0.06) and H. pylori infection.
CONCLUSION: These findings contribute to the understanding of the genetic variation between ethnicities, which may influence H. pylori susceptibility and the outcome of infection.
Methods: A database search was performed up to July 2019 inclusive for all studies that compared H. pylori infection in IBD patients vs. non-IBD controls. The relative risk (RR) was used to quantify the association between IBD and H. pylori, and the effects were combined across studies using a mixed-effects meta-regression model, which included IBD subtype and geographic region as categorical moderator variables.
Results: Our meta-regression model exhibited moderate heterogeneity (I2=48.74%). Pooled RR depended on both region (P=0.02) and subtype (P<0.001). Pooled RRs were <1 for all subtype and region combinations, indicative of a protective effect of H. pylori against IBD. The pooled RR was 28% (9%, 50%; P=0.001) greater for UC vs. CD and 43% (4%, 96%; P=0.02) greater for Mediterranean countries vs. East Asia. The pooled RR was 18% (-13%, 60%; P=0.48) greater for Europe vs. East Asia and 21% (-13%, 68%; P=0.42) greater for Mediterranean vs. Europe, though these differences were not statistically significant.
Conclusions: The protective effect of H. pylori on IBD varied by both subtype (more protection against CD vs. UC) and region (East Asia more protected than Mediterranean regions). Variation due to these effects could provide insight into IBD etiology.
METHODS: A large-scale prospective seroepidemiological study in West and East Malaysia using the HEL-p II commercial enzyme-linked immunosorbent assay kit (AMRAD, Melbourne, Australia) to detect H. pylori antibodies. Populations surveyed in West Malaysia were a rural community from Kuala Pilah, and blood donors from Kuala Lumpur and Kota Baru. Subjects studied in East Malaysia were volunteer blood donors from Kota Kinabalu, and blood donors and healthy volunteers from Sibu. Statistical analyses using multiple logistic regression analysis were carried out to identify independent risk factors for H. pylori infection
RESULTS: A total of 2,381 subjects were evaluated. H. pylori prevalence varied from different areas of study and ranged from a low of 26.4% in blood donors from Kota Baru to a high of 55.0% in Kota Kinabalu. The most striking differences, however, were noted in the prevalence rates among different racial groups. Prevalence rates among the Malays ranged from 11.9 to 29.2%, while the Chinese ranged from 26.7 to 57.5%, and those of Indians in two studies were 49.4 and 52.3%. In every location, Malays had a significantly lower prevalence compared with the other races. The highest prevalence rates were recorded among the indigenous races in Kota Kinabalu, East Malaysia. There was no difference between males and females in the studies. An increasing trend with age was noted in the majority of studies; however, no increase in prevalence rates was noted among the Malays.
CONCLUSIONS: The pattern of infection in a multiracial population in Malaysia points to a 'racial cohort' phenomenon. The infection appears to be confined to a racial group, with the Malays having consistently low prevalence rates. This observation may provide clues to the mode of transmission of infection.