Association of hysterectomy with bipolar disorder risk: A population‐based cohort study

BACKGROUND: Hormonal fluctuations may trigger the onset of bipolar disorder. We designed a longitudinal follow-up study to evaluate the association between hysterectomies and bipolar disorder risk. METHODS: We conducted a large retrospective cohort study using Taiwan's National Health Insurance Research Database. A total of 4,337 women aged 30 to 50 years who underwent the hysterectomy during 2000-2013 were selected and 17,348 patients without hysterectomy were selected for comparison (1:4 match). Poisson regression analysis was used to calculate the incidence rate ratio (IRR) and 95% confidence interval (CI). RESULTS: During the follow-up of 7.93 years, 20 participants with hysterectomy and 28 without hysterectomy developed bipolar disorder. Receiving hysterectomy was associated with the risk of developing bipolar disorder (adjusted IRR = 2.80; 95% CI = 2.54-3.09). Women with hysterectomy had a higher risk of bipolar disorder in follow-up durations of <1 year (adjusted IRR = 2.18 with 95% CI = 1.94-1.45) and ≥1 year (adjusted IRR = 2.85 with 95% CI = 2.58-3.15). Endometriosis and Premarin use increased bipolar disorder incidence in the hysterectomy group (adjusted IRR = 3.17 [95% CI = 2.83-3.56] and 4.22 [95% CI = 3.71-4.80], respectively). CONCLUSION: This study concluded that women with hysterectomy have an increased risk of bipolar disorder. Endometriosis and hormone therapy may add to the risk of bipolar disorder after hysterectomy. Knowledge about how surgical or natural hormonal withdrawal influences mood is fundamental and emphasizes the importance of coordinated psychiatric and gynecological care.