Risk of de novo severe carpal tunnel syndrome after bilateral oophorectomy: a population-based cohort study

OBJECTIVE: The incidence of carpal tunnel syndrome (CTS) is higher in women, and peaks around the age of menopause. Therefore, we investigated whether bilateral oophorectomy is associated with an increased risk of severe CTS. METHODS: We included all of the 1,653 premenopausal women who underwent bilateral oophorectomy for a nonmalignant indication between 1988 and 2007, and a random sample of 1,653 age-matched referent women who did not undergo bilateral oophorectomy in Olmsted County, Minnesota. Diagnoses of CTS assigned to women over their entire lifetime were identified in these two cohorts. The risk of de novo severe CTS after bilateral oophorectomy (or index date) was evaluated using Cox proportional hazards models adjusted for potential confounders. RESULTS: Bilateral oophorectomy was associated with an increased risk of severe CTS (adjusted hazard ratio 1.65, 95% confidence interval 1.20-2.25). The risk was suggestively greater in women with lower body mass index, nulliparity, and with a benign ovarian indication for oophorectomy (non-significant interactions). We did not observe a protective effect of estrogen therapy after the oophorectomy. The findings were similar in secondary analyses considering the incidence of CTS of any severity or idiopathic CTS. CONCLUSIONS: The risk of severe CTS, common in perimenopausal women, is increased after bilateral oophorectomy. The association may be causal or due to confounding. Therefore, the precise biological mechanisms explaining the association and the absence of a mitigating effect of estrogen therapy should be further investigated.