A preliminary study finds drugs already used to treat hypertension may help delay Alzheimer's, researchers at the University of Bristol suggest. Dr. Patrick Kehoe, co-leader of the Dementia Research Group at Frenchay Hospital in England, Richard Martin, Yoav Ben-Shlomo and Neil Davies in the University's School of Social and Community Medicine, used the General Practice Research Database, which holds anonymous data on approximately 10 million people treated by British primary care physicians. The study, published in the Journal of Alzheimer's Disease, found people age 60 and older who had ever taken one of two different groups of drugs that target the renin angiotensin system in the previous 10 years, had a 50 percent lower risk of developing Alzheimer's, with a more modest 25 percent reduced risk for forms of vascular dementia, compared to patients on any other types of hypertension drugs. The renin angiotensin system regulates blood pressure and fluid balance. This suggests that the benefits, if truly causal, are not merely due to a blood pressure lowering effect, and may involve specific biochemical alterations, Kehoe said. "Whilst our findings are interesting, these are not conclusive findings," Martin said in a statement. "We now need to do the clinical trials to properly test our observations."