Almost 10,000 Costa Ricans are over 90 years old, according to recent demographic data from the Central American Population Center at the University of Costa Rica. Luis Rosero Bixby, a researcher at the center, has followed ageing trends in the country since the 1970s, and has concluded that, for its income level, Costa Rica has one of the most long-lived populations in the world, reported the daily El País.

Rosero's research sparked interest by Dan Buettner, author of the best-selling book “Blue Zones: Lessons for Living Longer From the People Who've Lived the Longest,” published by National Geographic. Buettner traveled to Costa Rica's Nicoya Peninsula in 2007 with team of scientists and demographers to confirm Rosero's data. Buettner's Blue Zone Project now lists the Nicoya Peninsula along with Sardinia, Italy ; Ikaria, Greece ; and Loma Linda, California as one of the special places on the planet where conditions are allowing people to live beyond 90 and enjoy a higher quality of life.

How is it that Costa Rica, and its Nicoya Peninsula in particular, and have such a long-lived population? The answer is by no means clear or simple. El País quotes Rosero as saying, "For example, obesity levels in elderly men are especially low, but other indicators like blood pressure and cholesterol are not very good in Costa Rica, nevertheless people don't die from that." Buettner's Blue Zone study suggest a diet of whole corn tortillas, beans, and squash, combined with daily physical activity and a close social network contribute to the long and happy lives of an unusually high percentage of Nicoyans.

Some recent findings on youth lifestyles seem to suggest that the pattern of longevity among Nicoyans may be endangered. A recent study of 700 students aged 10-18 in Nicoya, Cañas, Santa Cruz and Liberia was reported on this week by the daily La Nación. The study found that youth watch up to 3.5 hours of TV per day and do less than an hour of exercise. Obesity averaged 14.2 percent, less than the national average for that age group of 21 percent, but a finding that 27.5 percent are underweight led to concerns of malnutrition. According to Pedro Ureña, the study's coordinator, family relations were cited as the most important factor in their quality life, reported La Nación.