I would greatly appreciate any comments and suggestions on our new research project "Exceptional Longevity in the United States", which we are developing now, see text at:
: I wonder if you found Leaf's reference. All long-lived communities in : the world are at altitude. : : Sci Am. 1973 Sep;229(3):44-52.
I have made this observation too after seeing the high life expectancy of people living in Andorra. Many long-lived populations are also islanders, eating fish. Fish contains omega-3 fatty acids, which reduce mortality, and phospholipids which may prevent from cognitive decline.