Aim: To investigate whether the pro- and anti-inflammatory cytokine gene polymorphisms, IL1B-511C/T, IL1B-31C/T, IL6-634C/G, TNF-1031T/C, TNF-857C/T, and IL10-1082A/G, interact with smoking and drinking habits to influence infection with H pylori.
Methods: The subjects were 410 Japanese transit company employees. C-reactive protein and conventional cardiovascular risk factors were evaluated. Serum anti-H pylori antibodies were measured. The genotypes of IL1B-511C/T, IL1B-31C/T, IL6-634C/G, TNF-1031T/C, TNF-857C/T, and IL10-1082A/G polymorphisms were determined by allelic discrimination using fluorogenic probes and a 5' nuclease assay.
Results: In gender- and age-adjusted logistic analyses, the subjects with TNF-857T/T had a significantly lower odds ratio (OR) for H pylori seropositivity (reference -857C/C; OR = 0.15, 95% CI: 0.03-0.59, P = 0.007). After stratification according to smoking and drinking status, among never-smokers, the subjects with IL1B-511C/T had a significantly lower OR (reference -511C/C; OR = 0.30, 95% CI: 0.10-0.90, P = 0.032). Among drinkers in the 1-5 times/wk category, the subjects with IL1B-511T/T had a significantly lower OR (reference C/C; OR = 0.38, 95% CI: 0.16-0.95, P = 0.039), and the subjects with IL1B-31C/T and T/T had a significantly higher OR (reference C/C; C/T: OR = 2.59, 95% CI, P = 0.042: 1.04-6.47; C/C: OR = 3.17, 95% CI: 1.23-8.14, P = 0.017). Among current smokers, the subjects with IL6-634C/G had a significantly higher OR (reference C/C; OR = 2.28, 95% CI: 1.13-4.58, P = 0.021). However, the interactions terms between the aforementioned genotypes and lifestyles were not statistically significant.
Conclusion: Contrary to previous findings, the results herein suggest that the TNF-857T/T genotype may be protective against chronic infection with H pylori. Drinking and smoking habits may influence the effect of cytokine gene polymorphisms. Further studies are required to clarify the effects of the pro- and anti-inflammatory cytokine polymorphisms and gene-environmental interactions on H pylori infection.