[Environmental Risk Factors for Dementia].

Owing to recent advancements in imaging techniques and biomarker research, the natural history of Alzheimer's disease (AD) has become clear from the very first preclinical stage. According to the study, more than 20 years before the onset of AD, Aβ starts to accumulate in the brain. This induces neurofibrillary tangle formation in the cerebral isocortex, leading to cognitive decline. If this process is suppressed, disease activity can be controlled. However, at this point, the best and most realistic way to deal with AD is to target the environmental factors that have been identified as risk factors by epidemiological studies.