Background: Numerous studies worldwide have explored the link between selenium levels and prostate cancer, yet their findings remain inconsistent. This systematic review and meta-analysis aimed to clarify this association by synthesizing results from analytical observational studies, including cohort and case-control studies. The insights from this meta-analysis could significantly impact healthcare decisions, clinical management, and treatment guideline updates.
Method: This study utilized a systematic review and meta-analysis approach, conducting a comprehensive literature search across international databases such as PubMed (Medline), Scopus, Web of Science, and Embase with relevant keywords. Articles were screened at the title, abstract, and full-text levels, followed by a quality assessment using the NOS checklist. Statistical analysis was performed using STATA version 17.
Results: After pooling data from eleven studies investigating the relationship between plasma or serum selenium and prostate cancer risk, findings indicated that higher selenium levels were associated with an 11% reduced risk of prostate cancer (RR= 0.89; 95% CI: 0.83 - 0.95; P-value= 0.03; I square= 34.46%). When selenium dosage was considered, with doses below 70 μg as the reference, individuals exposed to 130-160 μg exhibited a reduced cancer risk of 0.85 (RR= 0.85; 95% CI: 0.76 - 0.96; P-value= 0.18; I square= 27.37%), while those exposed to doses of 160 μg or higher had an RR of 0.89 (95% CI: 0.69 - 1.15; P-value= 0.19; I square= 0.00%). Additionally, an inverse relationship was found between selenium levels in toenails and prostate cancer risk (RR= 0.61; 95% CI: 0.50 - 0.75; P-value= 0.63; I square= 0.00%) and advanced prostate cancer (RR= 0.73; 95% CI: 0.67 - 0.80; P-value= 0.00; I square= 69.79%).
Conclusion: This meta-analysis suggests that selenium may have a protective effect against prostate cancer. Strategies to optimize selenium intake should be considered for prostate cancer prevention and management.
Keywords: Evidence Synthesis; Meta-analysis; Prostate Cancer; Selenium Level.