When I read these headlines I wonder "Causation? Correlation?". Maybe it's addressed in the study but.....

Is it that navigating with you brain is good to prevent Alzheimers? Or are you just more likely to die from something else as a cabbie. Statically speaking your more likely to die, than average, from a traffic related accident. Maybe the all the fumes cause something else terrible that kills you, etc.

It does seem logical to me that using your brain more could help offset these dementia related diseases. But it also seems like if that made a huge difference, we'd see statistically vastly more alzheimers in "low thought" jobs like retail cashiers and people who don't work/retire early vs say... collegiate professors.