Serum zinc status of patients with colorectal cancer: A systematic review and meta-analysis

Abstract

Introduction: Among the increasing number of cancer cases, colorectal cancer (CRC) cases are rising globally. The association of zinc in the neoplastic process of CRC is a major research avenue, yet the published reports have not provided any definitive conclusion. Objectives: We examined the association between serum zinc levels and CRC to test the potential of zinc dysregulation as a CRC susceptibility factor. Methods: In this systemic review and meta-analysis, we extensively searched EBSCOhost, EMBASE, Cochrane Library, ProQuest, PubMed/MEDLINE, Scopus, and Web of Science as well as manual screening by subject experts for studies reporting serum/plasma/blood zinc levels in CRC patients and control subjects till 27th August 2023. Based on a random effect model, we estimated the mean difference in serum/plasma/blood zinc levels between CRC cases and control subjects. Subgroup differences and publication bias were also investigated, along with a critical appraisal of included studies. Results: Eighteen studies with 8330 participants were included. The difference in serum zinc between CRC patients and control subjects was –5.01 µg/dl [95 % CI: −21.76 to 11.74; p = 0.56]. Omitting a highly influential outlier study, made this difference statistically significant at –13.28 µg/dl [95 % CI: −20.66 to -5.90, p < 0.01]. The difference between study effects could not be explained by the difference in analytical methods for zinc assessment, or type of blood samples. Conclusion: CRC patients had lower serum zinc levels. Some factors, such as different tumor grades of CRC, adenomas, and colonic polyps need to be further considered for a more conclusive association between serum zinc levels and risk for CRC.

Keywords

• Colorectal cancer
• Systematic reviews and meta-analysis
• Zinc
• Metals