Caught a story on the Oprah TV show talking about why the people living on the Nicoya peninsula on the Pacific coast of Costa Rica are long lived. And I asked myself, are these people long-lived? I haven’t heard that before and I should know.
So I went looking, and the special on Oprah was touting a book, The Blue Zones: Lessons for Living Longer From the People Who’ve Lived the Longest by Dan Buettner. Buettner first reported the story for National Geographic. So why does Buettner think Nicoyaians are long lived?
Some populations have been studied and found to be long lived–for example, there are four times as many centenarians in Okinawa, Japan compared to Japan as a whole.
Buettner’s source is Dr. Luis Rosero-Bixby, a Costa Rican demographer. The sole published source I can find is The exceptionally high life expectancy of Costa Rican nonagenarians. I haven’t read the paper, but from the abstract national birth registry data was used to establish date of birth and census data was used to monitor survival, and life expectancy of 90-year olds was found to be half a year longer than anywhere else in the world, for males only.
This seems very thin evidence, I can’t find other studies by Rosero-Bixby or evidence that these people were studied by any other groups. It is especially odd that the effect is seen in males but not females–this was the pattern in other areas where long survival was reported but didn’t pan out-the Caucus region of Georgia, northern Pakistan, and the Andean village of Vilcabamba in southern Ecuador. Usually remote areas with poor record keeping.