Correlation between reproductive factors and thyroid nodules in postmenopausal women

To explore the correlation of reproductive factors with thyroid nodules（TNs）in postmenopausal women in Lanzhou, Gansu Province so as to provide reliable strategies for the prevention and treatment of TNs.

A total of 2 270 postmenopausal female residents aged 43 and over living in Tianqingjiayuan, Guangwumen and Xicun Street Communities for longer than 5 years in Lanzhou from 2014 to 2016 were recruited as the research objects. The data of menarche age, menopausal age, time of pregnancy, time of delivery, time of abortion and pregnancy complications were surveyed and collected through questionnaires. Thyroid ultrasound examination was performed. Multivariate logistic regression analysis was used to explore the correlation between female reproductive factors and TNs.

The prevalence of TNs was 60.97%（1 384/2 270）in postmenopausal women in Lanzhou, and the prevalence was increased gradually with the increase of age（Chi-square_trend=66.761, P<0.001）. The patients in the TNs group had significantly older age, larger proportions of non-higher education level, hypertension, diabetes and smoking, higher levels of WC, HC, SBP, FBG, 2hPG, HbA1c, TG, Crea and UA levels, and lower HDL-C, TSH, FT3, TGAb and TPOAb levels when compared with those in the non-TNs group. The prevalence of TNs was increased obviously with the increase of times of pregnancy and childbirth and older menopausal age（time of pregnancies: Chi-square_trend=11.874, P=0.001; time of delivery: Chi-square_trend=37.385, P<0.001; menopausal age: Chi-square_trend=8.897, P=0.003）. Multivariate logistic regression analysis showed that the risk of nodules was increased for those with postmenopausal age over 55 years than those with the age <45 years（OR=2.372, 95%CI: 1.142~4.926, P=0.021）. No notable correlation was observed in menarche age, abortion times, ectopic pregnancy, contraceptive/estrogen history, macrosomia, pregnancy complications, breastfeeding, menopausal type and other factors with TNs.

The prevalence of TNs is quite high in menopausal women in Lanzhou, which is affected by many factors. Among them, the delayed menopausal age is a high-risk factor for the prevalence. Therefore, we should focus on strengthening the thyroid ultrasound examination of perimenopausal women, so as to find the existence early for early intervention.