Reproductive and menstrual factors for papillary thyroid cancer risk: A case-control study in Chinese women.

Abstract Background Thyroid cancer (TC) is threefold more common in women than men. Reproductive and menstrual factors may be related to the onset of papillary thyroid cancer (PTC). This study aims to determine the association of reproductive and menstrual factors with PTC in Chinese females. Methods A total of 335 histologically confirmed cases of PTC were recruited in this case-control study. The controls were matched for age with a deviation of ± 2 years, which conducted from September 2016 to February 2019. Logistic regression models were applied to identify the association of reproductive and menstrual factors with PTC. Results After adjustment by some variables, early menarche age (OR ≤ 13 years vs. > 13years = 2.40, 95 % CI 1.12−5.13) and shorter lifetime breastfeeding (OR  24 years = 0.66, 95 % CI 0.44−0.98). There was a positive correlation between premenopausal and PTC in the lower age group (OR premenopausal vs. Menopause by natural =2.34, 95 %CI 1.03−5.28). Conclusions Early menarche age, abortion, shorter breastfeeding duration and premenopausal may be related to the occurrence of PTC. Early age at first pregnancy and larger number of full-time pregnancies were possible to decrease the risk of PTC.