Shin S, et al. - Among Japanese women, researchers examined the links between menstrual and reproductive issues and risk of thyroid cancer. Using a self-administered questionnaire in women aged 40–69 years, information was obtained on menstrual and reproductive history. A total of 187 newly diagnosed cases of thyroid cancer were found from 1990–2012. They used Cox proportional hazards regression to calculate the hazard ratios and 95% confidence intervals for menstrual and reproductive factors and incidence of thyroid cancer. Findings supported a link between the development of thyroid cancer with early age at menarche for premenopausal women and surgical menopause and late age at natural menopause for postmenopausal women. The hypothesis that exposure to estrogens increases the risk of thyroid cancer was supported.