A recent study in California showed a correlation between the altitude at which people live and the rate at which they die of Alzheimer's disease.
But before you pack your bags and move to the Himalayas, it's important to note that correlation is not causation.
In other words, high altitude alone may not be the reason people seem to develop Alzheimer's at a rate up to 50 percent lower. It could be the lifestyle associated with living at higher altitudes, including the rural environment and more physical activity.
It's also important to understand that the study only takes into account where people die, not where they have lived most of their lives.
As with almost everything, more research is needed, but if high altitude alone proves to be a significant factor in reducing the rate of Alzheimer's disease, then "head for the hills" will take on a whole new meaning.