METHODS: Male subjects included in this study were drawn from those undergoing routine annual medical examinations offered by their employers. Venous blood was obtained from these patients after an overnight fast and from which genomic DNA was extracted. Genotyping was carried out by polymerase chain reaction (PCR) followed by digestion with restriction enzyme NciI. Personal and family medical history of the subjects were also taken.
RESULTS: The genotype distribution of the individuals studied was in accordance to a population at Hardy Weinberg equilibrium. The frequency of the PI(A2) allele was 0.1, 0.01 and 0.01 in the Indians, Malays and Chinese, respectively. The differences in frequencies of the PI(A2) variant are significant among different ethnic groups (P<0.001 for Indians vs. Chinese and Indians vs. Malays).
CONCLUSIONS: We observed a significantly higher frequency of the PI(A2) allele among Indians relative to the Chinese and Malays in Singapore. The effect of this genotype may partially explain the higher rate of ischaemic heart disease seen among Indians compared to the Chinese and Malay ethnic groups.
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.