Anticholinergic Medication Use and Fractures in Postmenopausal Women: Findings from the Women’s Health Initiative

Background: Anticholinergic medication use has been associated with several negative health outcomes in older adults, but little is known about its risk for fractures. Objective: To examine the association between anticholinergic medication use and fracture outcomes in community-dwelling postmenopausal women. Methods: Utilizing a prospective cohort design, we examined data collected from 137,408 women aged 50–79 years from the Women’s Health Initiative observational study and clinical trials not reporting hip fracture at baseline. Medications with moderate or strong anticholinergic effects were identified directly from drug containers during in-person interviews. The main outcome was fractures (hip, lower arm/wrist and total fractures). We performed multivariable Cox proportional hazard survival modelling to assess the association between anticholinergic use and the risk of fractures. Results: At baseline, 10.6 % of the women were using an anticholinergic medication, of which antihistamines were the most common medication class (48.4 %). The multivariable-adjusted hazard ratios for anticholinergic medication use were 1.08 (95 % confidence interval [CI] 0.89–1.30) for hip fracture, 1.01 (95 % CI 0.91–1.13) for lower arm/wrist fracture and 1.03 (95 % CI 0.98–1.09) for total fractures. We observed no association according to subclass or count of anticholinergic medications, or trends between the duration of anticholinergic use and any of the fracture outcomes. Conclusion: Anticholinergic medication use was not associated with an increased risk of fractures among community-dwelling women. Future research should make efforts to capture over-the-counter medication use and the cumulative anticholinergic burden in relation to important health outcomes for older adults.