Clinical and environmental risk factors of Helicobacter pylori, gastric cancer, and gastric microbiome signature in a South African cohort

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dc.contributor.advisorSetshedi, Mashiko
dc.contributor.advisorBrink, Adrian
dc.contributor.authorFrancis, Innocent Ekparolaguaziba
dc.date.accessioned2026-06-22T10:04:08Z
dc.date.available2026-06-22T10:04:08Z
dc.date.issued2026
dc.date.updated2026-06-22T09:58:24Z
dc.description.abstractBackground: Helicobacter pylori (H. pylori) is a Type 1 carcinogen associated with gastric cancer (GCA) and other gastroduodenal diseases. Despite high H. pylori prevalence in Africa, reported GCA incidence remains paradoxically low, a phenomenon known as the ‘African enigma'. This study aimed to investigate the validity of this paradox through a systematic review, retrospective cohort analysis, and prospective study of H. pylori-infected individuals. Methods: The study comprised three components: (1) a systematic review evaluating the epidemiology of GCA in Africa, (2) a retrospective cohort study analyzing GCA incidence and associated risk factors at Groote Schuur Hospital, and (3) a cross-sectional study examining the molecular signature of H. pylori strains and gastric microbiome diversity in affected patients. Results: the systematic review highlighted significant limitations in current data, stressing the need for standardized national registries and comprehensive epidemiological studies. The retrospective study confirmed that GCA mainly affects males aged 60 and above, with non- cardia cancers being the most common subtype. The protective effect of proton pump inhibitors against antral cancer was also observed. The cross-sectional study revealed that the H. pylori strains among Africans had fewer virulence factors (cagPAI variants, virB/D genes) compared to Southeast Asian strains, potentially explaining lower GCA incidence. Additionally, H. pylori infection tends to alter the gastric microbiome diversity, with distinct microbial compositions across racial groups. Conclusions: Findings support the ‘African enigma', suggesting that specific H. pylori strain characteristics and microbiome alterations may contribute to the lower observed GCA incidence in Africa. Future research should integrate multi-omic analyses to further elucidate host-pathogen interactions and disease mechanisms.
dc.identifier.apacitationFrancis, I. E. (2026). <i>Clinical and environmental risk factors of Helicobacter pylori, gastric cancer, and gastric microbiome signature in a South African cohort</i>. (). University of Cape Town ,Faculty of Health Sciences ,Department of Medicine. Retrieved from http://hdl.handle.net/11427/43342en_ZA
dc.identifier.chicagocitationFrancis, Innocent Ekparolaguaziba. <i>"Clinical and environmental risk factors of Helicobacter pylori, gastric cancer, and gastric microbiome signature in a South African cohort."</i> ., University of Cape Town ,Faculty of Health Sciences ,Department of Medicine, 2026. http://hdl.handle.net/11427/43342en_ZA
dc.identifier.citationFrancis, I.E. 2026. Clinical and environmental risk factors of Helicobacter pylori, gastric cancer, and gastric microbiome signature in a South African cohort. . University of Cape Town ,Faculty of Health Sciences ,Department of Medicine. http://hdl.handle.net/11427/43342en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Francis, Innocent Ekparolaguaziba AB - Background: Helicobacter pylori (H. pylori) is a Type 1 carcinogen associated with gastric cancer (GCA) and other gastroduodenal diseases. Despite high H. pylori prevalence in Africa, reported GCA incidence remains paradoxically low, a phenomenon known as the ‘African enigma'. This study aimed to investigate the validity of this paradox through a systematic review, retrospective cohort analysis, and prospective study of H. pylori-infected individuals. Methods: The study comprised three components: (1) a systematic review evaluating the epidemiology of GCA in Africa, (2) a retrospective cohort study analyzing GCA incidence and associated risk factors at Groote Schuur Hospital, and (3) a cross-sectional study examining the molecular signature of H. pylori strains and gastric microbiome diversity in affected patients. Results: the systematic review highlighted significant limitations in current data, stressing the need for standardized national registries and comprehensive epidemiological studies. The retrospective study confirmed that GCA mainly affects males aged 60 and above, with non- cardia cancers being the most common subtype. The protective effect of proton pump inhibitors against antral cancer was also observed. The cross-sectional study revealed that the H. pylori strains among Africans had fewer virulence factors (cagPAI variants, virB/D genes) compared to Southeast Asian strains, potentially explaining lower GCA incidence. Additionally, H. pylori infection tends to alter the gastric microbiome diversity, with distinct microbial compositions across racial groups. Conclusions: Findings support the ‘African enigma', suggesting that specific H. pylori strain characteristics and microbiome alterations may contribute to the lower observed GCA incidence in Africa. Future research should integrate multi-omic analyses to further elucidate host-pathogen interactions and disease mechanisms. DA - 2026 DB - OpenUCT DP - University of Cape Town KW - Groote Schuur Hospital KW - Helicobacter pylori LK - https://open.uct.ac.za PB - University of Cape Town PY - 2026 T1 - Clinical and environmental risk factors of Helicobacter pylori, gastric cancer, and gastric microbiome signature in a South African cohort TI - Clinical and environmental risk factors of Helicobacter pylori, gastric cancer, and gastric microbiome signature in a South African cohort UR - http://hdl.handle.net/11427/43342 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/43342
dc.identifier.vancouvercitationFrancis IE. Clinical and environmental risk factors of Helicobacter pylori, gastric cancer, and gastric microbiome signature in a South African cohort. []. University of Cape Town ,Faculty of Health Sciences ,Department of Medicine, 2026 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/43342en_ZA
dc.language.isoen
dc.language.rfc3066eng
dc.publisher.departmentDepartment of Medicine
dc.publisher.facultyFaculty of Health Sciences
dc.publisher.institutionUniversity of Cape Town
dc.subjectGroote Schuur Hospital
dc.subjectHelicobacter pylori
dc.titleClinical and environmental risk factors of Helicobacter pylori, gastric cancer, and gastric microbiome signature in a South African cohort
dc.typeThesis / Dissertation
dc.type.qualificationlevelDoctoral
dc.type.qualificationlevelPhD
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