Helicobacter pylori and cytokine gene variants as predictors of premalignant gastric lesions

Table 1 Statistical methods used in mentioned original research articles that analysed the relationship between cytokine gene variants and premalignant gastric lesions

Ref.	Target population (sample size)	Cytokine SNPs1	Outcomes	Confounding factors/other covariates	Control for confounding/covariate effect	Statistical methods
[73]	Chinese adult patients (1330)	IL-8-4073, IL-18RAP917997, IL-1Brs1143627, IL-1B rs1143634, IL-1Brs16944, IL-4Rrs2057768, IL-10rs1800896, IL-22rs1179251, IL-32rs2015620	ChAG risk	Age, sex, smoking status, H. pylori	Stratification, adjustment	χ2 test, multivariable logistic model with interaction term, Synergy index
			IM risk
			DYS risk
			GC risk
[75]	Slovenian adults (318)	TNF-α -308, IL-1RN, IL-1B -511	ChAG risk	Gender	Adjustment	χ2 test, Multivariable logistic model
			GC risk
[76]	German older adults (1068)	TNF-α -308, IL10T-819C, IL10A-1082G, IL1AC-889T, IL1B C-511T, IL1RN 9589T, IL8 T-251A	ChAG risk	Age, gender	Adjustment	Multivariable logistic model
[83]	Peruvian Amerindian adults (334)	IL-1B-511, IL-1RN	ChAG risk	Age, gender, H. pylori	Adjustment	χ2 test/Fisher’s exact test, multivariable logistic model
			GCrisk
[84]	Venezuelan adults (109)	IL-1B-31, IL-1B-511, IL-1B+13954, IL-1RN	ChAG risk	H. pylori	Adjustment	χ2 test/Fisher’s exact test, univariable logistic model
			GI risk
			LI risk
[87]	Costa Rican adults (223)	IL-1β-511, IL-1β-3954, IL-1RN intron 2, IL-10 -1082, IL-10 -592	AG risk	Sex, age, H. pylori	Adjustment	χ2 test/Fisher’s exact test, multivariable logistic model
			CoAG risk
			IM risk
[96]	Venezuelan adults (2033)	IL4 –590, IL4R -3223, IL4R -398, IL10 –1082	AG risk	Age, sex, H. pylori, education, environmental factors	Adjustment	χ2 test/Fisher’s exact test, multivariable logistic model
			IM risk
			DYS risk
[101]	Brazilian adults (112)	IL-6	ChG	None	None	χ2 test/Fisher’s exact test
			GC
[102]	Japanese adults (863)	IL-8 -251, IL-1B -511, IL-1RN	AG	Age, sex, H. pylori	Adjustment	χ2 test/Fisher’s exact test, multivariable logistic model
			GC
[103]	Chinese adults (372)	IL-8-251	Severe ChAG risk	Age, gender	Stratification, adjustment	χ2 test, multivariable logistic model, Synergy index
			IM risk
[106]	Chinese adult patients (556)	IL-10-1082, IL-10-819, IL-10-592	AG risk	Age, sex, H. pylori	Stratification, adjustment	χ2 test, multivariable logistic model with interaction term
			GC risk
[108]	Brazilian adults (227)	IL-6-174, IL-8-251, IL-10-819	Gastritis, peptic ulcer, GC	H. pylori infection	Stratification	χ2 test/Fisher’s exact test
[111]	Chinese adults H. pylori (302)	IL-1B-511	IM risk	Age	Adjustment	χ2 test/Fisher’s exact test, univariable/multivariable logistic model

Only the original research articles containing analysis of cytokines’ genotypes (not haplotypes) were included.

¹Only the discussed cytokine SNPs of interest (and not all of SNPs mentioned in the above studies) are described. AG: Atrophic gastritis; CoAG: Corpus atrophic gastritis; ChAG: Chronic atrophic gastritis (the term used in original research); ChG: Chronic gastritis; DYS: Dysplasia; GC: Gastric cancer; GI: Granulocytic infiltration; IM: Intestinal metaplasia; LI: Lymphocytic infiltration; H. pylori: Helicobacter pylori.