Association between hysterectomy and dementia risk in Korean women aged 40-59: a nationwide retrospective cohort study.

objectiveTo determine whether hysterectomy for benign diseases is associated with the risk of dementia in middle-aged women.

methodsWe conducted a retrospective cohort study using data from the Korean National Health Insurance Service database (2002-2020). Women aged 40-59 years who underwent hysterectomy for benign indications (n=16,818) were propensity score-matched (1:1) to controls who had not received hysterectomy. Subjects were followed up until the diagnosis of dementia, death, or the end of the study period (2020). Dementia (all types), Alzheimer's disease (AD), and vascular dementia (VaD) were identified by International Classification of Diseases, 10th revision codes. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for dementia associated with hysterectomy.

resultsMedian follow-up was 11.4 years. Dementia occurred in 302 (1.8%) women who did not undergo hysterectomy and 257 (1.5%) women who underwent hysterectomy (P=0.061). Cox analysis revealed that hysterectomy was not significantly associated with all-cause dementia (HR, 0.865; 95% CI, 0.724-1.033), with a non-significant trend towards reduced risk. Subgroup analysis also failed to identify any significant association; AD (HR, 0.696; 95% CI, 0.463-1.048) and VaD (HR, 0.625; 95% CI, 0.284-1.377) were not significantly associated with an increased hazard.

conclusionIn this large Korean cohort, hysterectomy for benign diseases in women aged 40-59 years was not associated with a significant change in the subsequent risk of dementia. Collectively, our results indicate that hysterectomy was not associated with an increased incidence of dementia, including in analyses stratified by adnexal surgery.