Meanwhile, in US death certificate data…

Taxi drivers rarely die of Alzheimer's theconversation.com

Of hundreds of occupations tracked in death records, taxi and ambulance drivers show among the lowest rates of dying from Alzheimer's disease. The proposed explanation is that a career spent building and rebuilding mental maps of a city keeps the hippocampus, the first region the disease usually attacks, unusually busy. It is a correlation, not a prescription, but it is a strange and specific one.