Purpose: Thyroid cancer has a higher incidence in women than in men, and it has been hypothesized that hormonal factors may explain such disparity. We performed a meta-analysis of observational prospective studies to investigate the association between menstrual and reproductive variables and exogenous hormone use and the risk of thyroid cancer among women.
Methods: We calculated summary relative risks and 95 % confidence intervals (95 % CI) using random effect models.
Results: Overall, 5,434 thyroid cancer cases from twenty-four papers were included. Increasing age at first pregnancy/birth (SRR 1.56, 95 % CI 1.01–2.42) and hysterectomy (SRR 1.43, 95 % CI 1.15–1.78) were associated with thyroid cancer risk. Women that were in menopause at enrolment had a reduced thyroid cancer risk (SRR 0.79, 95 % CI 0.62–1.01). No other menstrual, reproductive, and hormonal variable was associated with thyroid cancer risk.
Conclusions: Menstrual and reproductive factors may play a role in the etiology of thyroid cancer, possibly through the mediation of estrogen receptors.
- Hormone use
- Menstrual factors
- Reproductive factors
- Thyroid cancer
ASJC Scopus subject areas
- Cancer Research