Angiotension receptor blockers reduce the risk of dementia

OBJECTIVE: Recent studies implied that angiotension receptor blockers (ARBs) not only have an antihypertensive effect but also have beneficial effects on dementia. The purpose of this study was to investigate the effects of ARBs on dementia and the subtypes. METHODS: We conducted a population-based cohort study with data from the Taiwan National Health Insurance Research Database. A total of 24 531 matching pairs (1 : 1) of ARB-exposed and non-ARB-exposed patients were included. Each patient was individually tracked from 1997 to 2009 to identify incident cases of dementia (onset in 1999 or later). Cox proportional hazard regressions were employed to calculate the hazard ratios and 95% confidence intervals (CIs) for the association between ARBs and dementia, Alzheimer's disease and vascular dementia, conditional for matching pairs. RESULTS: There were 1322 cases (5.4%) of dementia in the ARB cohort and 2181 cases (8.9%) in the non-ARB cohort identified during the 11-year follow-up period. The multivariate-adjusted hazard ratios for dementia, Alzheimer's disease and vascular dementia were 0.54 (95% CI 0.51-0.59), 0.53 (95% CI 0.43-0.64) and 0.63 (95% CI 0.54-0.73) for patients with ARB treatments, respectively. In terms of cumulative dosage, patients with more than 1460 defined daily dose of ARBs had less risk than those patients with less than 1460 defined daily dose (hazard ratio 0.37 vs. 0.61; P < 0.05). CONCLUSION: These results suggest that ARB may be associated with a reduced risk of dementia in high vascular-risk individuals. Patients exposed to ARBs for higher cumulative doses experienced more protection from dementia and the subtypes.