It’s insufficient. For example, the people who develop Alzheimer’s may for whatever reason may be less likely to survive the profession where Alzheimer’s is the cause of death (eg getting into a fatal car accident where undiagnosed early onset is the problem). Bus drivers typically drive the same route over and over and probably have safer trips overall than taxi and ambulance drivers.

It’s a plausible hypothesis but it’s really really hard to tease things out and controlling for age is the obvious thing but that doesn’t get you the conclusive result you think it does.