Such a small number of outcomes matter because statistical precision depends on the number of relevant events. With only 10 Alzheimer’s deaths, even a small change in the count could substantially alter the estimated association.

Taxi drivers provided more robust data, with 171 Alzheimer’s deaths among 16,658 decedents, but death-certificate Alzheimer’s mortality may not reflect how often taxi drivers develop the disease. Differences in diagnosis or cause-of-death reporting across occupations could influence the observed association.

The large overall sample does not eliminate uncertainty in the much smaller occupational subgroups, particularly among ambulance drivers.

Nonetheless, this is an interesting study and merits further investigation.

In addition there's the social component of driving - you may not always want to talk to a Taxi driver but many people do. And ambulance drivers are often socializing with their colleagues

Driving also has a mix of reaction time based skills and hand eye and hand foot coordination. Overall it's pretty complicated.

Writing this I'm realising the final "Turing" test for AI might actually be just replacing the average Taxi driver. Can it drive a car, choose a route dynamically based on day and traffic and weather, and have a conversation with a wide variety of people and topics all at the same time ?