Table 2

Study results evaluating markers of H. pylori infection in patients with micronutrients deficiency

Study (Year)	H. pylori diagnosis		Description of the Indicators	Outcomes	Limitations/strength
Study (Year)	Antibody/targeted molecule	Method	Description of the Indicators	Outcomes	Limitations/strength
Ali et al (2018)40	Anti-Helicobacter pylori IgA	ELISA	Iron	Significant positive correlation between iron deficiency and H. pylori-positive cases.	Smaller sample size, limited access data, study purpose was highly focused.
Felkner et al (2007)38	Anti-Helicobacter pylori IgG	ELISA	Ferritin, folate, vitamin B₁₂	No association was found between micronutrients and H. pylori-positive cases.	Larger sample size, well-validated study, sample was collected in just after post partum.
Golalipour et al (2012)37	Anti-Helicobacter pylori IgG	ELISA	Ferritin, folate, vitamin B₁₂	No association was found between micronutrients and H. pylori-positive cases.	Smaller sample size, sample was collected in just after post partum.
Mulayim et al (2008)39	Urease	¹⁴C-urea breath test	Iron	Significant positive correlation between iron deficiency and H. pylori-positive cases.	Data were not normally distributed when calculated for iron deficiency.
Mubarak et al (2014)36	Anti-Helicobacter pylori IgA	ELISA	Ferritin	There is a no link between iron deficiency, anaemia, and thrombocytopenia with H. pylori-positive cases.	Larger sample size, well-validated study, limited biasness
Ugwuja et al (2010)35	Anti-Helicobacter pylori IgG	ELISA	Copper, iron and zinc	Trace elements (Cu, Fe, and Zn) are not significantly associated with H. pylori positive cases	Larger sample size, limited access data, highly biased.