There are several potentially modifiable risk factors for Alzheimer’s disease (AD), including obesity, diabetes and smoking, but the causality of these associations is unclear. New insights come from an analysis of the International Genomics of Alzheimer’s Project (IGAP) database, which includes 17,008 individuals with AD and 37,154 cognitively normal elderly controls.
Using a technique called Mendelian randomisation to test causality, the researchers found that gene variants that predict higher systolic blood pressure are associated with a higher probability of taking antihypertensive medication and with a decreased risk of AD.
“These findings suggest that higher blood pressure — or some environmental exposure associated with higher blood pressure, such as use of antihypertensive medications — may reduce AD risk,” the team concludes in PLoS Medicine
(online, 16 June 2015).
 Ãstergaard SD, Mukherjee S, Sharp SJ et al. Associations between potentially modifiable risk factors and Alzheimer disease: a Mendelian randomization study. PLoS Medicine 2015;12(6):e1001841. doi:10.1371/journal.pmed.1001841.