Is it possible that neurosurgeons don't actually have a higher rate of Alzheimer's Disease, but just get correctly diagnosed more often than the general population? I suspect a lot of poor people with limited access to health care die of that disease but it never gets labeled or recorded. But neurosurgeons can recognize their own symptoms and generally have access to the best possible care.

The only way to be sure would be to perform detailed autopsies on a large random sample of the population.