Does regular caffeine use reduce the risk of cognitive disorders like dementia and Alzheimer's disease?

While some epidemiological studies find a relationship between greater long-term daily caffeine intake (through coffee or tea) and a lower risk of later life cognitive decline or cognitive disorders, others find an inverse relationship and some studies find no relationship at all.^[1][2][3][4] A main limitation in such epidemiological studies is that caffeine intake is based on a questionnaire-based retrospective recall of caffeine-containing beverages and foods overall several months or years. Furthermore, the epidemiological data finds no evidence of a dose-response relationship between long-term caffeine intake and cognitive function.^[2][3] Consequently, an overall conclusion cannot be made from the epidemiological data; well-designed randomized controlled trials or cohort studies are needed to make firm conclusions about the effects of long-term caffeine intake and the risk of cognitive disorders like dementia and Alzheimer’s disease.