Increased risk of dementia in patients with osteoporosis: a population-based retrospective cohort analysis.

Osteoporosis is a common systemic skeletal disease that predominantly affects people older than 50 years and often co-occurs with dementia. The purpose of this study was to evaluate the risk of dementia in osteoporosis patients in Taiwan. Using data from Taiwan's National Health Insurance Research Database (NHIRD), we identified 23,941 patients with osteoporosis from 2000 to 2010 and 47,579 nonosteoporosis control patients, frequency-matched for age, sex, and index year, excluding patients with dementia at the baseline. We conducted univariate and multiple Cox proportional-hazards regression analyses to calculate the hazard ratios (HRs) and 95 % confidence intervals (CIs) of the association between osteoporosis and risk of dementia. After adjustment for potential risk factors, the osteoporosis patients exhibited 1.46-fold and 1.39-fold higher risk of dementia (95 % CI = 1.37-1.56) and Alzheimer's disease (95 % CI = 0.95-2.02), respectively, compared with the matched nonosteoporosis patients. We observed increased risk of dementia in both men and women with osteoporosis. The osteoporosis patients receiving bisphosphonate treatment or estrogen supplementation were associated with significantly lower risk of dementia compared with the osteoporosis patients who did not receive any treatment. Overall, our results suggest higher risks of dementia in osteoporosis patients than in nonosteoporosis patients. Osteoporosis could thus be considered an early risk factor for dementia. Future large-scale double-blind randomized clinical trials are required to clarify the role of medication in osteoporosis-related dementia.