To synthesize observational evidence and quantify the association between infertility and thyroid cancer risk, addressing inconsistencies in existing epidemiologic evidence.
Key Findings:
Infertility is associated with a significantly higher risk of thyroid cancer (RR, 1.37; 95% CI, 1.15–1.63) based on nine studies with a total of 4,563,090 participants.
Stronger association observed among men (RR, 1.53; 95% CI, 1.43–1.65) compared to women (RR, 1.31; 95% CI, 1.04–1.66).
Substantial heterogeneity across studies (I² = 81.9%).
Association remained significant after adjusting for small-study effects.
Interpretation:
The findings suggest a potential link between infertility and increased thyroid cancer risk, warranting further investigation into underlying mechanisms.
Limitations:
Substantial heterogeneity among included studies.
Potential confounding factors not fully addressed.
Limited number of studies included in the analysis.
Potential biases inherent in observational studies.
Conclusion:
Infertility appears to be associated with an increased risk of thyroid cancer, but further well-designed research is necessary to clarify this association.
