Zinc Status and Occurrence of Thyroid Cancer: Systematic Review and Meta-Analysis

Area of Science:

• Endocrinology
• Oncology
• Nutritional Science

Background:

• Thyroid cancer (TC) is the most common endocrine tumor, with rising incidence.
• Trace element imbalance, particularly zinc (Zn), is implicated in thyroid function and pathogenesis.
• Zn is vital for thyroid hormone action and may play a role in TC development.

Purpose of the Study:

• To systematically review and meta-analyze the association between low serum zinc concentrations and TC occurrence.
• To synthesize current evidence on the role of zinc in thyroid cancer pathogenesis.

Main Methods:

• Systematic search of major databases (PubMed, Scopus, Embase, LILACS, Web of Science) until December 2024.
• Inclusion of 10 observational studies (7 case-control, 3 cross-sectional).
• Meta-analysis using random effects models, assessing heterogeneity with I² statistic.

Main Results:

• Serum zinc levels did not significantly differ between TC patients and healthy controls (mean difference: -251.77).
• High heterogeneity (I² = 100%) indicates very low certainty of the findings.
• Included studies had small sample sizes (44-294 individuals).

Conclusions:

• Current evidence does not support a significant association between low serum zinc and thyroid cancer.
• Further high-quality observational studies with larger, representative samples are essential.
• Improved control of confounding variables is crucial for future research.