Association between Early Menopause, Gynecological Cancer, and Tobacco Smoking: A Cross-Sectional Study.

Background: The rates of smoking among women are rising. Previous studies have shown that smoking is associated with early menopause. However, the association of gynecological cancer, including breast and cervical cancer, with early menopause and smoking, remains unclear. Therefore, this study aimed to determine the association between smoking and early menopause, breast cancer, and cervical cancer.

Methods: This cross-sectional study used data from the Korean National Health and Nutritional Survey Examination (KHANES) (2016-2018). Early menopause was defined as menopause before 50 years of age.

Results: A total of 4,481 participants were included in the analysis. There was no association between early menopause and cervical cancer (adjusted odds ratio [aOR]: 1.435, 95% confidence interval [CI]: 0.730-2.821), but women who had experienced early menopause had a significantly higher risk of breast cancer than women who had experienced normal menopause (aOR: 1.683, 95% CI: 1.089-2.602, p=0.019). Early menopause was not associated with an increased risk of breast cancer in ever-smoker (aOR: 0.475, 95% CI: 0.039-5.748), but was associated with a significantly increased risk of breast cancer in never-smokers (aOR: 1.828, 95% CI: 1.171-2.852).

Conclusions: Early menopause was associated with an increased risk of breast cancer in women who had never smoked, but not in women who had ever smoked.