ABlue zone is a places in the world which has a high concentration of centenarians in addition to clusters of people who have lived beyond the age of 60-years without disease and/or other health conditions such as obesity, cancer, diabetes, and heart problems.[1] Examples of blue zones are listed below. The name "blue zones" derived simply during the original survey by demographers, who used a blue marker on a map to mark the villages with long-lived population.[1][2]
Initial analysis was that the apparent longevity of blue zone populations resulted from practice of a traditional lifestyle involving intense physical activity beyond the age of 80-yers in predominantly rural areas, with low levels of stress, excellent family and community support, who consume locally produced, seasonal, fresh foods. It was postulated that the remarkably good health status during ageing could be the result of a delicate balance between the benefits of a traditional lifestyle with those of modernity (increased wealth and better medical care).[1]
The epidemiological study "AKEntAnnos. The Sardinia Study of Extreme Longevity" (AKEntAnnos is a Sardinian phrase which means approximatively “Health & life up to 100”) of centenarians living in a large island in the Mediterranean sea [3] was enhanced by the experimental gerontological study in Sardinia which led to the introduction of the concept of the "Blue Zone" by Michel Poulain with Gianni Pes, Luca Deiana and other colleagues in terms of locations with populations experiencing rates of above-average longevity funded by the US National Institute on Aging (Duke University) the MaxPlanck Institute for Demographic Research (MPIDR) the government of Sardinia.[2][1] This seminal work that developed the concept of blue zones grabbed global attention when first presented at the International Union for the Scientific Study of the Population conference in 2000 where a short paper by Poulain was presented about the validation of exceptional male longevity in Sardinia and then again with the full article on the Identification of a geographic area characterized by extreme longevity in the Sardinia island: the AKEA study (AKEA being an acronym for AKEntAnnos) in the journal of Experimental Gerontology in 2004.[2] The work identified Sardinia's Nuoro province as the region with the highest concentration of male centenarians, referring to the area as the "blue zone" (a term chosen simply because the authors happened to use blue ink to mark a map of the regions with many centenarians).[1][2] Author Dan Buettner added to this work with his article for National Geographic in 2005 that really popularised the concept outside of the academic realm [4]
In the original study of centenarians living in 14 mountain villages of Sardinia (the first proposed blue zone), the research team developed an Extreme Longevity Index (ELI) representing the ratio between the number of eventual centenarians born between 1880 and 1900, and the total number of births recorded during the same time interval for the region.[1] The ELI was defined as the number of centenarians per 10,000 newborns, and was equated to the probability for any person born in that municipality to reach 100 years old and remain functional.[1]
During the period of births between 1880 and 1900 in the Sardinia blue zone, 47 men and 44 women eventually reached age 100, giving an average ELI value per 100,000 births of 508 for the blue zone location, whereas the rest of Sardinia had ELI values 2–4 times lower (less longevity).[1]
Another longevity index applied was the Centenarian rate (CR) for the 1900 birth group (number of persons surviving to 100 years old per 10,000 people alive at age 60) in December 2000.[1] The Sardinia and Okinawa blue zones had CR values for men substantially higher compared to several other countries, whereas values for women were mostly above those in other countries, while comparable to others.[1]
Several possible errors or limitations exist for these estimates, such as unreliability or absence of birth records.[1]
Life expectancy in blue zones is proposed to be as much as a decade or longer, compared to the average world life expectancy of 73 years in 2019.[7][8][medical citation needed]
Eat wisely, without surfeit and locally available seasonal fresh foods
Avoid stress and sleep well following the diurnal cycle of the sun, going to sleep at sunset and waking at sunrise
Maintain strong family ties, sharing lives with children/grandchildren and enjoying frequent celebrations together
Strong social networks & community support, where elders are valued for their continuing contributions to the community
Deep traditions that include respect for nature and community
Life purpose based in spiritual beliefs
Marketing
Dan Buettner's extensive exploration, writings and collaborations led to founding the marketing company, Blue Zones® LLC, with Poulmais and trademarking the term. Buettner also added Loma Linda, California, to Poulain's list of blue zones. Buettner describes the Seventh-Day Adventist community there as having unusual longevity due putatively to a healthy lifestyle and plant-based diet.[7][8] In 2020, Blue Zones® was acquired by the Seventh-Day Adventist health care system, Adventist Health.[10]
Critiques
The concept of blue zones having exceptional longevity has been challenged by the absence of the scientific method being used to produce evidence-based information[11] and by the substantial decline of life expectancy during the 21st century in one of the blue zones, Okinawa.[12]
Harriet Hall, writing for Science-Based Medicine, stated that there are no controlled studies of elderly people in the blue zones, and that blue zone diets are based on speculation, not evidence through a rigorous scientific method.[11]
A study validate the claims of longevity in Okinawa was unable to verify whether residents were as old as they reported due to many records not surviving World War II.[13] When analyzed in the 21st century, life expectancy in Okinawa was deemed to no longer be exceptional when compared to the rest of Japan, as "male longevity is now ranked 26th among the 47 prefectures of Japan."[12]
^ abcdefghijklmPoulain, Michel; Herm, Anne; Pes, Gianni. The Blue Zones: areas of exceptional longevity around the world in: Vienna Yearbook of Population Research, vol. 11, 2013, p. 87–108. backup Quote: "...These populations succeeded in maintaining a traditional lifestyle implying an intense physical activity that extends beyond the age of 80, a reduced level of stress and intensive family and community support for their oldest olds as well as the consumption of locally produced food...Based on a strict validation method, the ages of Sardinian centenarians were thoroughly proven to be correct (Poulain et al. 2006)... [footnote 2:] The term was chosen simply because at the time the authors used a blue pen on a map to mark the villages with long-lived population... [definition:] In practice, a blue zone (BZ) is defined as a rather limited and homogenous geographical area where the population shares the same lifestyle and environment and its longevity has been proved to be exceptionally high. [] Other validated BZs have been found so far in Okinawa (Japan), on the Nicoya peninsula (Costa Rica) and on the island of Ikaria (Greece)...The extreme longevity area identified in Sardinia and named as Blue Zone (BZ) includes a group of 14 villages in Barbagia and Ogliastra, covering the highest mountain area of Sardinia.4...Starting from 2005, in cooperation with D. Buettner, a journalist writing for National Geographic, the BZ concept was extended to other relevant regions of the earth (Buettner 2012). Exceptional longevity at population level has been identified and validated so far in three other settings: the island of Okinawa in Japan, the peninsula of Nicoya in Costa Rica and the island of Ikaria in Greece (Figures 3)..."
^Deiana L, Ferrucci L, Pes GM, Carru C, Delitala G, Ganau A, Mariotti S, Nieddu A, Pettinato S, Putzu P, Franceschi C, Baggio G. AKEntAnnos. The Sardinia Study of Extreme Longevity. Aging (Milano). 1999 Jun;11(3):142-9. https://pubmed.ncbi.nlm.nih.gov/10476308/
^Buettner, D. (2005). The secrets of longevity. National Geographic, November 5–26. ngm.nationalgeographic.com/features/world/europe/italy/longevity-text
^Poulain, M., Naito, K. (2004). L’évolution de la longévité à Okinawa, 1921-2000 (2004). Cahiers québécois de démographie, 33,1 29–49 https://doi.org/10.7202/010851ar
