Blue Zone, a Demographic Concept and Beyond

Abstract

The concept of Blue Zone (BZ) refers to regions with exceptionally high concentrations of centenarians, often in good health. Four BZs have been validated, Okinawa (Japan), Sardinia (Italy), Nicoya (Costa Rica), and Ikaria (Greece), with Martinique recently emerging as the fifth. Despite their popularity, BZs face criticism regarding data reliability, particularly the accuracy of centenarians' ages. This article reviews the process used to identify a BZ through a three-step methodology. First, it outlines the strict age validation procedures used to confirm longevity claims. Second, it reviews key demographic indicators to assess population longevity. Third, it defines BZ criteria, using the Sardinian BZ as a reference and requiring the eligible area to show a longevity level at least 50% higher than the national average. Martinique meets these criteria, while Galicia’s validation is still ongoing. The study also highlights core longevity factors—diet, physical activity, social support, and environment—and underscores the importance of adopting the 7 BZ principles to foster longer, healthier lives worldwide. The BZ thus remains a valuable model for understanding the impact of lifestyle on aging and for applying these insights in public health and lifestyle medicine strategies.

“A demographic analysis of more than 2000 centenarians confirmed Martinique’s exceptional longevity and its BZ status.”

Introduction

The Blue Zone (hereafter BZ), an area where the population lives longer—a demographic concept initiated 25 years ago ¹ —has become a key topic and an inspiration for Lifestyle Medicine. Even more important than the discovery of exceptionally long-lived populations, the BZ concept serves as a global benchmark for understanding the factors that contribute to a healthy and long life, such as diet, social relationships, cultural traditions, and environmental factors. The philosophy that has emerged from the study of BZ populations encourages people to embrace a more natural lifestyle, prioritize social connections, and cultivate a sense of purpose, which can help improve our daily lives. Nowadays, the BZ philosophy has become an umbrella term for a wide range of initiatives and activities that could be developed in local communities to help people live longer and healthier together.

In 2005, a groundbreaking article was published in National Geographic describing the environment and lifestyle of BZ populations. ² In 2008, explorer and journalist Dan Buettner, the author of this article, founded Blue Zones LLC ³ and launched Blue Zone projects in several communities across the United States ⁴ to promote the lifestyle principles followed by populations living in BZs. In 2020, Blue Zones LLC was acquired by Adventist Health, a non-profit corporation that provides health care in the western United States, and advocates for a holistic approach to public health at the community level to enhance well-being and extend lifespan. ⁵

On May 14, 2024, Blue Zones LLC and the American College of Lifestyle Medicine (ACLM) announced a partnership to accelerate a lifestyle-first approach within the entire health care system. ⁶ This partnership is positioned as an alliance that champions lifestyle medicine as a catalyst for longevity by building healthy communities together. In this announcement, Blue Zones LLC is described as the global leader in longevity research and well-being solutions, while ACLM is the leading organization for promoting lifestyle medicine. Together, they propose an evidence-based roadmap for living a longer and healthier life, drawing from their research on BZs—the world’s longest-lived, healthiest, and happiest communities. This new partnership is considered to be a monumental leap forward in preventive health as each physician and primary care provider who becomes trained in lifestyle medicine will promote BZ principles and contribute to the well-being of the population at the local community level. ⁶

Despite the positive messages conveyed by BZs to enhance societal well-being, the concept has recently been widely criticized in the media. On October 24, 2024, New York Times published an article written by Dana G. Smith titled “Do People in ‘Blue Zones’ Actually Live Longer?”, with the following subtitle: “The premise is catchy, but some think it’s based on faulty data.” ⁷ This question arose in connection with a preprint circulated by a demographer who long criticized longevity studies by questioning the validation of the age of alleged centenarians. This type of information attracts journalists eager for sensational stories. Dana G. Smith, for instance, wrote that BZs are poor areas that generally had terrible outcomes at old age, and are the epitome of bad record keeping, inflating the number of centenarians. In the same article, Nir Barzilai from the Albert Einstein College of Medicine confirmed that the concept of Blue Zones is consistent with what we know about aging but nevertheless argued that the Blue Zones themselves have not necessarily been validated scientifically. This statement serves as the primary motivation for writing this paper, which aims to detail the methodology used to identify a BZ—a demographic concept introduced in 2000 to define populations worldwide with exceptional longevity. Refuting this claim is the main motivation behind this article, which introduces the demographic concept of BZ and details the methodology introduced in 2000 to define exceptionally long-lived populations worldwide.

Individual Longevity and Population Longevity

Longevity research has long focused primarily on the individual level, analyzing each centenarian individually. Validating the claimed ages of centenarians has always been a crucial aspect of such studies. To ensure accuracy, the Committee for Age Validation of Exceptional Long-Livers (CAVE) was established in Tallinn in June 2016 as part of the group of scientists managing the International Database on Longevity (IDL). ⁸ Demographers are strict when handling age; age misreporting, particularly age exaggeration, must be ruled out before research can be conducted to understand and explain why these individuals live longer. ⁹ Consequently, demographers specialized in extreme longevity review all administrative documents, carry out interviews, and check available statistical data to validate the ages of numerous exceptionally long-lived individuals worldwide. ¹⁰ A more detailed explanation of the validation process is provided later in this paper. Once the ages of individual centenarians have been successfully validated, researchers turn their focus to identifying the determinants of individual longevity. To do this, the characteristics of validated centenarians are compared with a suitable control group consisting of individuals whose ages are also validated, but who did not reach 100 years of age.

While individual longevity refers to a single individual, population longevity refers to an entire population. As with individual longevity, the first step in identifying an exceptionally long-living population is to examine the ages of its oldest members. Indicators of an exceptionally long-living population include high life expectancy, an unusually high prevalence of centenarians, and the presence of a significant number of individuals, either alive or deceased, who have reached an exceptionally old age, compared to those in other populations. However, these factors alone are not sufficient to determine whether a population is exceptionally long-living. Once the accuracy of the age of each centenarian within the population has been verified, the next step is to determine whether their number is relatively higher than that of other populations. A population can be classified as exceptionally long-living, and its region of origin can be called a longevity hotspot, only if a relatively higher number of people born in that region live to exceptionally old age, based on longevity indices discussed later in this article.

First Attempts to Discover Populations with Exceptional Longevity

Explorers and missionaries were the first to take an interest in the world’s longest-lived populations. In 1973, Alexander Leaf ¹¹ published an article in National Geographic magazine, in which he extolled the extraordinary longevity of the populations he had visited in Abkhazia in the Caucasus, the Hunzas in Upper Pakistan, and the community of Vilcabamba in Ecuador. According to Leaf, these regions had ten times the number of centenarians compared to most Western countries. He noted that all these areas were characterized by poor sanitation, high rates of infectious diseases, high infant mortality, illiteracy, and a lack of modern medical care, making the extreme longevity of the inhabitants even more astonishing.

A few years later, however, Mazess and Forman ¹² demonstrated that age exaggeration was prevalent in Vilcabamba, with many men and women exaggerating their age to improve their social status or to promote local tourism. Moreover, neither the Hunzas in Pakistan nor the Abkhazians in the Caucasus had sufficiently reliable data to confirm the alleged extraordinary ages of these centenarians.

Against this backdrop, demographers became increasingly concerned about the accuracy of longevity claims in the final decade of the 20th century. This scrutiny led to a systematic refutation of all previous claims about long-lived populations worldwide. Upon closer examination, most of them turned out to be false or impossible to verify due to insufficient documentation. As a result, the search for longevity hotspots in the closing decades of the 20th century was largely unsuccessful.

The Identification of the Four First Blue Zones

Sardinia

In 1999, the publication of data showing extreme male longevity in Sardinia ¹³ and their presentation at the IDL annual meeting in Montpellier raised sharp questions among demographers about the validity of the alleged ages of Sardinia’s oldest people. Michel Poulain, described in the journal Science as a “crack historical demographer,” ¹⁴ was invited to visit Sardinia to answer this question along with the Sardinian physician Gianni Pes. They applied a rigorous method to confirm the ages of Sardinian centenarians. Amazingly, and contrary to the prevailing opinion of most demographers, after thorough verification, these ages were confirmed to be accurate. ¹⁵

The successful age validation of a sample of 40 Sardinian centenarians was received with skepticism by demographers, even prompting a counter-validation investigation six years later. The conclusions of the final report written by Bertrand Desjardin and Bernard Jeune, both active members of CAVE, confirmed the existence of exceptional longevity in the mountainous regions of Sardinia. ¹⁶

In this context, the first BZ was identified by discovering that the spatial distribution of Sardinian centenarians based on their place of birth was far from random. ¹ During the validation process in the spring of 2000, an area comprising 14 villages in the mountainous regions of Ogliastra and Barbagia was identified as places where the probability of reaching 100 years of age was found to be twice as high as in the rest of Sardinia.

An article detailing these findings was published in September 2004 by Experimental Gerontology ¹ where this region was first referred to the Longevity Blue Zone, or simply Blue Zone (BZ). The term BZ was chosen simply because the villages with many long-lived individuals were marked on a map of Sardinia, with a blue pen.

Shortly after the validation of the first BZ in Sardinia, several sites worldwide were studied as potential hotspots of longevity, including mountain villages on the Greek islands of Crete and Rhodes, as well as a region in Cyprus, and the Caucasus Mountains of Georgia. In none of these locations the necessary data to confirm their alleged extraordinary longevity was found. Even, in Georgia, some documents were found (supplemental document # 1) that proved that the reported ages of some of the oldest people were incorrect and significantly exaggerated. ¹⁷

Okinawa

In November 2001, Makoto Suzuki and his research team presented their findings on more than 1000 centenarians who have been surveyed since 1975 in the Okinawan Centenarian Study. ¹⁸ In close cooperation with Okinawan researchers, the accuracy of the age and number of centenarians was collected to assess the level of longevity indices and their evolution in Okinawa. ¹⁹

Although Japanese data on centenarians, obtained from annual lists of centenarians taken from the Koseki, Japan’s population registration system, are considered reliable, ²⁰ the extraordinary longevity observed in Okinawa is still a matter of debate. The original Koseki was largely destroyed during the Battle of Okinawa in 1945 and was later reconstructed by American authorities. This has led to debates about the reliability of Okinawan longevity claims, ²¹ as errors may have occurred during the reconstruction process after World War II.

Because of limited access to individual data in Japan for confidentiality reasons, it has not been possible to identify errors in age reporting or in calculating longevity indicators. Despite these uncertainties, the apparent longevity advantage of the Okinawan population over generations born before World War II remains remarkable. More recent investigations based on the most recent Okinawan cohorts of centenarians born up to 1923 have confirmed this finding, as well as Okinawa’s status as a BZ. ²²

At the same time, American writer and explorer Dan Buettner received support from National Geographic to visit Okinawa and investigate possible factors contributing to the exceptional longevity of this population. After the publication of the first article validating the BZ in Sardinia, ¹ Dan Buettner contacted the Sardinian team. In his 2005 article in National Geographic, ² he noted that demographers coined the term “Blue Zone” while discovering exceptional longevity in Sardinia. He also included the Adventist community of Loma Linda as the third longevity hotspot, following a specific request from the editor to include an American example. However, the longevity in Loma Linda cannot be measured by using the same methodology as for other validated BZs. Although the health study of Californian Adventists confirmed their advantage in life expectancy, ²³ these Adventists had been born all over California, while the whole population of Loma Linda was not involved in the study. Moreover, it is well known that religious communities—and more specifically monks and nuns—follow a strict lifestyle that favors their longevity. ²⁴

Nicoya

In 2006, Dan Buettner and National Geographic established closer cooperation to identify and validate other BZs around the world. Following the work initiated by Luis Rosero-Bixby, ²⁵ Costa Rica was selected as a potential candidate. Confirming his findings, it was found that male longevity in Costa Rica was exceptionally high compared to the United States and other developed countries.

More detailed data showed that in the Nicoya Peninsula in the northwestern part of the country, five cantones had a higher proportion of men aged 80 and over than the rest of Costa Rica, according to the 2000 census. However, due to possible age exaggeration, the census data alone were considered insufficient to confirm longevity in the region.

As a result, a comprehensive field study was conducted in early 2007, and a thorough analysis of the Civil Registry and vital statistics on deaths provided strong evidence that the population in these five cantones were indeed long-living. The possibility of age misreporting—often observed among the oldest-old worldwide—was considered highly unlikely after the systematic age validation of 35 centenarians interviewed in the region. Moreover, migration flows were limited in Nicoya due to the relative isolation of the peninsula, which reduced the potential impact of external demographic influences.

This study officially confirmed the five cantones as a validated BZ in February 2007. Unfortunately, data collection on new centenarians has not continued since then. Recent investigations by Rosero-Bixby ²⁶ suggest that the longevity advantage in Nicoya may be waning. This trend appears to be driven primarily by cohort effects: while Nicoyan men born in 1905 had an adult mortality rate that was 33% lower than that of other Costa Ricans, those born in 1945 had rates that were 10% higher. Rosero-Bixby concluded that hotspots of extreme longevity are likely transient and should be continually reassessed.

Ikaria

In the fall 2007, the search for a new BZ continued in Vilcabamba, Ecuador, the place Leaf had visited in the 1970s for its alleged exceptional longevity. However, a thorough analysis of statistical data from INEC, Ecuador’s National Institute of Statistics and Censuses, did not reveal any region in the country with extraordinary longevity.

At the request of National Geographic to identify another BZ, the attention was turned to Greece, where the media often highlighted the longevity of the Cretan population and the benefits of the island’s diet. At the time of visit to Crete in 2000, no place on the island qualified as a BZ due to a lack of reliable data. Fortunately, in 2007, the National Statistical Service of Greece (NSSG) made available more precise demographic data, including data from the population register (dimotologio) and the 2000 census by age and sex, as well as mortality data for each Greek municipality (dimoi). A detailed analysis of this data pointed to the island of Ikaria and its three municipalities as potential candidates for a BZ.

An initial visit to the island in February 2008 confirmed this hypothesis. Subsequently, in April 2008, an in-depth investigation on Ikaria in collaboration with Dan Buettner and with the support of National Geographic allowed us to interview more than 30 centenarians and confirm their ages. As a result, Ikaria was officially recognized as the fourth BZ. Even though several studies have been conducted since then on the local population across various disciplines, it has not been possible to update the necessary demographic data to confirm whether Ikaria can still be considered as a BZ.

Later, after the identification of Nicoya and Ikaria as the third and fourth BZs, studies were conducted in the Bama Valley and the region of Shangri-La in China, the island of Rodrigues in Mauritius, Menorca in Spain, various locations in Cuba and in Barbados in the Caribbean, several villages of the Cilento region of Campania in Italy, and others in the Parco delle Madonie in Sicily. In most of these locations, the available information and documents did not allow the alleged extraordinary longevity to be verified, and consequently the existence of another BZ could not be confirmed.

The table in Annex 1 lists all the places visited so far to verify the alleged extraordinary longevity of their populations. It also describes the different steps taken during the studies, and the results achieved.

Demographic Criteria for the Validation of a Blue Zone

The validation of a BZ is based on rigorous scientific research methods. Designating an area as a BZ first requires validation of the individual longevity of the oldest people living in the candidate area. Once this step is completed, the validated centenarians must be exhaustively counted in the second step. Importantly, a BZ, which is an area with an exceptionally high number of centenarians, cannot be identified simply by grouping municipalities with a high number of centenarians. Instead, more specific indicators and statistical methods should be used to validate population longevity, as presented below in the second step of the validation process. The third step completes the validation process, as described below for the most recently studied areas of Martinique and Galicia.

First Step: Validation of Individual Longevity

The first step in identifying a BZ and confirming exceptional longevity is to validate the individual ages of people in the population. This includes checking the exact age at death of each deceased centenarian, and confirming the date of birth of each living centenarian. For deceased persons, validation requires an unambiguous link between birth and death records. For living centenarians, a specific birth record must be attributed without ambiguity, ruling out any age misreporting or exaggeration.

Perls et al. ²⁷ noted that claims of extreme longevity often turned out to be false during verification. Young et al. ²⁸ documented various cases of extreme age invalidation, while Poulain ²⁹ applied strict validation criteria to a selection of allegedly long-living individuals. The most reliable sources for age validation are births and deaths records from civil registration. For living centenarians, additional evidence, such as a birth certificate or other official documents, is required to verify age. Marriage records can also help establish identity.

Civil registration of births, marriages, and deaths began in France after the 1789 Revolution, in Italy in 1866, and in Spain in 1871, continuing earlier church records dating back to the Middle Ages. These records provide legal confirmation, including name, birth and death details, and marital status. Two cases presented in supplemental documents #2 and #3 illustrate the challenges encountered when validating a person’s age based on registration records, as well as why other sources, such as population registers, family books, passports, identity cards, tax and military records, and census data, may be useful in some cases.

It is important to understand how these documents are created and updated. Errors may result from self-reported information, family declarations, or administrative transcription errors. Age exaggeration can also happen due to personal or social motivations. A case outlined in supplemental document #1 describes in detail how a person who died on September 17, 2002, in Georgia (Caucasus) at the alleged age of 111, appeared to have aged 20 years in just 10 years—from 1938 to 1948—as shown in successive family books.

All available information must be cross-checked for age validation. In some cases, reconstructing the centenarian’s family tree is necessary. Interviews with centenarians and their relatives can be useful, but due to possible memory impairments, age validation should not rely solely on them. The reported ages must correspond with demographic patterns for the given period and population.

As early as in 1873, Thoms ³⁰ argued that age validation should be beyond dispute. Jeune et al. ³¹ disagreed with the principle of “jusqu’à preuve du contraire” and concluded that it was more effective to focus on the conditions that could lead to falsification, rather than trying to corroborate possible false assumptions. If a critical piece of information is missing, it is impossible to conclude with absolute certainty that the validation is beyond doubt. However, if any element is found to be incorrect, the whole validation process must be considered as invalid. In the end, it is easier to disprove that someone is a centenarian than to prove it. While validation can never be considered final, revocation is final even if only one clear ground for invalidation is found.

Second Step: Validation of Population Longevity

In research and media coverage of populations with exceptional longevity, centenarian prevalence (CP)—the proportion of centenarians in a given population—is widely used, as the necessary data to calculate this indicator are usually available. However, CP is not always reliable for the validation of a BZ, as changes in demographic processes over time have an impact on its results. For example, in a population with high immigration or a baby boom, the proportion of older people is artificially reduced. Conversely, a population with significant emigration among younger generations or a lower number of newborns, will have a proportion of older people that is artificially inflated. Consequently, CP may be unreliable for cross-population comparisons, although it remains a preferred longevity indicator among gerontologists and media reports.

Compared to CP, life expectancy provides a somewhat better measure of longevity, and allows for better comparisons between different populations. A life table is traditionally calculated based on a hypothetical cohort to which the mortality rates for each age group at a given time are applied; accordingly, it does not account for mortality change over time. In practice, computing a life table is not a straightforward exercise, and the resulting life expectancy is not considered the best tool for comparing extreme longevity across time and space, or for identifying a potential BZ.

An alternative indicator, the centenarian rate (CR), introduced by Robine et al., ³² compares the number of 100-year-olds with the number of 60-year-olds in the same population 40 years earlier. Relatively easy to calculate using census data, CR is said to eliminate the impact of the size of the cohort, the role of migration, naturalization, fertility, and infant mortality. However, CR may still be biased if migration flows between ages 60 and 100 are significant. Such an indicator is useful for national comparisons, but less so for smaller populations. A broader approach could compare census cohorts over time, such as by comparing people aged 60-69 in 1970, and those aged 90-99 in 2000.

To better assess longevity, the extreme longevity index (ELI) was introduced. ¹ It measures the probability that a newborn in the observed area will become centenarian, simply by comparing the number of centenarians (alive or dead) to the number of newborns in the same cohort, a century earlier. Compared to the other indicators described above, ELI is more stable and reliable since it is based on individually verified centenarians, and the number of centenarians used in the calculation is much larger. Moreover, it cannot be overestimated as double counting is eliminated. However, it may be slightly underestimated if some newborns who emigrated abroad and became centenarians are unaccounted for.

For the practical assessment, ELI considers births a century ago (excluding stillbirths), and centenarians from the same birth cohorts, whether alive or dead. The total number of people born during the reference period, such as between 1907 and 1920, is used for comparison across BZs. Expressed as the number of centenarians per 100,000 newborns in the same birth cohort, ELI provides a more accurate measure of population longevity, and is essential for validating new BZs.

Third Step: Validation of a Blue Zone

A BZ was initially defined as an area where the population is characterized by a significantly higher level of longevity compared with neighboring regions, provided that the exceptional longevity of people in this population has been fully validated. In practice, it is a rather limited and homogeneous geographical area where the population shares the same lifestyle and environment, and its longevity has been proven to be exceptionally high. ³³

The Sardinian BZ validated in 2000 is used as benchmark for the validation of a new BZ. Birth cohorts involved in identifying the first Sardinian BZ were born between 1880 and 1900. To ensure a correct comparison between Sardinia and potential new BZ, the extent of the Sardinian BZ has been revised based on data provided by ISTAT, the Italian Statistical Institute, by considering the number of centenarians born between 1907 and 1920 in each municipality of birth in Sardinia. The same Gaussian smoothing method and a spatial deterministic model were used as for the identification of the first BZ. ¹ The updated Sardinian BZ shown (on the right in Figure 1) is larger than the original one (on the left). It covers 44 municipalities compared to 15 in the original BZ, and the value of the ELI is 1327 per 100,000 newborns, compared to 509 in the first exercise. The value of 1327 for ELI in the Sardinian BZ can be compared to the value of ELI 739 for Italy calculated with data extracted from the Human Mortality Database. ³⁴ This means that longevity in the Sardinian BZ is 67% higher than in Italy (Table 1).

Figure 1.

Spatial determination of the BZ in Sardinia based on the cohort born between 1880 and 1900 (left), and between 1907 and 1920 (right) (see Poulain et al. 2004 for the initial BZ, while the results on the new map elaborated by Claude Grasland are not yet published).

Table 1.

Calculation of ELI Values for the Different Areas Under Study, and the Ratio Between Each BZ or Alleged BZ and Their Corresponding Countries.

Blue Zone	Sardinian BZ	Martinique	Galicia	Alleged Galician BZ
Numbers of newborns (N)	31 727	68 711	848 598	61 583
Number of centenarians (C)	421	1 419	5 897	623
ELI (C/N per 100.000 newborns)	1 327	2 065	695	1 012
Country	Italy	France	Spain	Spain
Numbers of newborns (N)	14 176 430	8 764 797	8 752 492	8 752 492
Number of centenarians (C)	112 443	99 257	70 308	70 308
ELI (C/N per 100.000 newborns)	793	1 132	827	827
ELI BZ/ELI Country	167%	182%	84%	122%

Taking the Sardinian BZ as a reference, the following two criteria should be met for an area to be designated as a BZ:

• (1) The ELI value should be equal to or higher than the value of ELI computed for the Sardinian BZ.

• (2) The ELI value should be at least 50% higher than the corresponding value computed for the country as a whole.

Assessing Blue Zone Status in Martinique and Galicia

Inspired by the work of Jacques Vallin, ³⁵ who identified a significant number of supercentenarians in Guadeloupe and Martinique, the latter was considered as possible BZ, and investigated accordingly. In ten of the island’s 34 municipalities, centenarians were validated based on civil registration records, and several were interviewed in person to confirm their demographic data and genealogy. The data were then systematically updated using monthly mortality records from the French Government. ³⁶ A demographic analysis of more than 2000 centenarians confirmed Martinique’s exceptional longevity and its BZ status. Recently, in collaboration with the University of Vigo, longevity in the province of Ourense (Galicia, Spain) was investigated, and the reliability of the age of centenarians was confirmed by visiting them and verifying administrative records.

To test whether Martinique and Southern Galicia can be granted BZ status, the value of ELI was computed for the same birth cohorts, those born between 1907 and 1920. For Martinique, there were 1419 centenarians born between 1907 and 1920 per 68,711 newborns from the same birth cohorts. The computed ELI (2065 centenarians per 100,000 newborns) is higher than the ELI calculated for the Sardinian BZ, and higher than the one calculated for France based on data extracted from the Human Mortality Database (Table 1). The ELI for Galicia was calculated using data from the 2022 census, and the number of centenarians who have died during the last decades by municipality of birth, obtained from the IGE (Galicia’s Statistical Institute). The ELI was calculated for Galicia (ELI = 695) and for 34 municipalities in the south of the region, as suggested by the research team of the University of Vigo in Ourense (ELI = 1012). These values were compared with similar ones computed for Spain (ELI = 827), based on data extracted from the Human Mortality Database (Table 1).

Based on the established criteria, Martinique qualifies as a BZ, while neither Galicia nor the alleged Galician BZ meet the threshold for this designation as a BZ. However, research is ongoing with data from INE (Spain’s National Statistical Institute) to identify a homogeneous cluster of municipalities in Galicia or elsewhere in Spain where longevity levels, as measured by the ELI, could justify BZ status.

Figure 2 illustrates ELI trends in 14 birth cohorts for the Sardinian BZ, Martinique, and the Galician alleged BZ compared to their respective countries, using a 3-year moving average (see Annex 2). The data reveal:

• • A general upward trend in ELI values, underscoring the importance of analyzing identical birth cohorts for comparative studies.

• • A significant increase in the number of centenarians across all regions, regardless of the post-WWI baby boom.

• • A widening longevity advantage between the Sardinian and Martinique BZs and their respective national averages.

• • A sharp increase in ELI for the most recent birth cohorts in the Galician alleged BZ, suggesting that further longevity research in Galicia is crucial.

Figure 2.

Evolution of ELI for the generations born from 1907 to 1920 for the six areas under study (three years mobile averages). Detailed figures are proposed in Annex 2.

The Blue Zones and Beyond

The concept of BZ has sparked extensive research across various disciplines. In these regions, the factors or behaviors contributing to increased life expectancy are widely shared among the population, thereby increasing the likelihood of identifying key explanatory variables. Many individuals are born and spend their entire lives in these areas, making them ideal for studying longevity. Researchers are increasingly focusing on understanding the relative contributions of genetics, lifestyle, social interactions, diet, and the physical environment, all of which are considered crucial to exceptional longevity. Several studies have specifically explored the higher longevity observed in various BZs, leading to the development of a field now known as Blue Zone Science.

Blue Zone Science

Blue Zone Science has developed rapidly, with over 100 scientific papers exploring the factors behind exceptional longevity in these regions. However, few studies have examined the various factors associated with longevity in specific BZs, such as Ikaria,^37,38 Nicoya, ³⁹ and Sardinia, ⁴⁰ or conducted comparative perspective, such as those between Nicoya and Sardinia. ⁴¹ These studies suggest that the exceptional longevity observed in different BZs results from a set of interrelated factors that affect diet, physical activity, social life, and psychological well-being.

Many studies have specifically examined nutrition and dietary habits in BZs. The diet in these regions is rich in vegetables, whole grains, and healthy fats (olive oil, nuts), with moderate consumption of animal proteins and refined sugars.^42,43 Polyphenol intake and the use of wild plants play key roles in protecting against cellular aging.^44,45 In addition, certain gut microbiota profiles have been associated with longevity, influenced by local dietary habits, particularly fermented dairy products and fiber-rich vegetables. ⁴⁶ Further research is needed to confirm that diet is a direct cause of longevity, considering that the typical BZ diet is often neither homogeneous across the population nor stable over time. Moreover, it differs significantly between various BZs. ⁴⁷

Stress management in BZs involves cultural and spiritual practices. Religious faith, gratitude, and family support enhance well-being, life satisfaction, and community ties. These populations share a positive philosophy of life, characterized by a sense of purpose and a serene approach to aging, which helps reduce depression and enhance resilience.^48,49 In Okinawa, this concept is known as ikigai, referring to the “reason for being” that motivates people every day. In Nicoya, the term “plan de vida” reflects a similar approach. ⁵⁰ In Sardinia, the integration of and respect for older people contribute to their psychological well-being. ⁵¹

The genetic specificity of populations in different BZs is also considered a potential factor in their longevity. Epigenetics, the study of how environmental factors influence gene expression, although often viewed secondary to lifestyle, remains an area that requires further attention and exploration.^52-54

These studies show that longevity in BZs does not stem from a single factor but on a holistic combination in which diet works in conjunction with regular physical activity, a strong social network, and proactive stress management. Despite medical advances, many deaths in industrialized societies occur between the ages of 60 and 80, suggesting that improvements in health care are often offset by less healthy lifestyles. The BZ lifestyle model provides valuable guidelines for global well-being and healthy aging, referred to as the “Living Blue Zone.”

Living Blue Zone

In BZ populations, remarkable health and longevity may result from a balance between the benefits of modernity and the preservation of traditional lifestyles. Promoting the fundamental principles of a natural and simple life found in BZs could contribute to longer and healthier lives in modern societies, aligning with pillars of Lifestyle Medicine.

The seven scientifically studied BZ principles^55,56 are closely aligned with the six pillars of lifestyle promoted by the ACLM, ⁵⁷ and with the seven Lifestyle Medicine pillars proposed by Stanford University. ⁵⁸ Table 2 compares all these with the Power 9 recommendations from Blue Zones LLC. ⁵⁹ There is a clear similarity between the seven BZ principles and the Lifestyle Medicine pillars, all grounded in evidence-based science aimed at promoting behavioral change. However, a primary distinction lies in their perspective: the Lifestyle Medicine pillars focus on individual care using person-centered techniques, while the BZ principles prioritize public health at the community level. ⁶⁰ The Power 9 recommendations ⁵⁹ also show similarities, but include elements that have not been scientifically observed in BZs. For example, “Plant Slant,” a very low-meat diet that favors beans, resembles vegetarian or vegan lifestyles, but is not consistently prominent in BZs. Similarly, “Wine@5” which encourages moderate alcohol consumption, may not fully align with Blue Zone Science.

Table 2.

Comparing the 7 Principles for Living Blue Zone, the 6 Pillars of the ACLM, the 7 Pillars of the Standford LM and the Power-9 of Blue Zones LLC.

7 BZ Principles55,56	6 Pillars of the ACLM 57	7 Pillars of the Standford Lifestyle Medicine 58	9 Power Principles 59
1. Move naturally	2. Physical activity	1. Movement & exercise	1. Move naturally
2. Eat wisely	1. Whole food, Plant-based nutrition 4. Avoidance of risky substances	2. Healthful nutrition	4. 80% Rule 5. Plant Slant 6. Wine @ 5
3. Avoid stress and get plenty of sleep	3. Stress management 5. Restorative sleep	4. Stress management 3. Restorative sleep 7. Cognitive enhancement	3. Downshift
4. Strong family ties and community support	6. Social connection	5. Social engagement	7. Belong 8. Loved Ones First 9. Right Tribe
5. Respect the planet
6. A purpose in life		6. Gratitude & reflection	2. Purpose
7. Ensure the legacy for future generations

In addition to the demographic significance and exotic appeal of BZs, their popularization has made them an important source of inspiration for shaping the future of modern society. The idea of a “Living Blue Zone” should be promoted in communities, as emphasized by Appel, ⁶¹ who concluded that what is currently limited to a few populations could 0become commonplace. However, the critical question remains: how can the lessons from the BZs be applied to promote healthy aging in post-industrial societies? The BZ model offers a framework for integrating evidence-based lifestyle principles into modern life. With the adoption of the seven BZ principles, societies can expect significant improvements in health, longevity, and well-being.

In 2008, following the publication of the book “The Blue Zones: Lessons for Living Longer From the People Who’ve Lived the Longest,” Dan Buettner trademarked the term “Blue Zone,” founded Blue Zones LLC, and thereafter launched the Blue Zones Project. ⁴ The Blue Zones Project is a community-led initiative that transforms neighborhoods and social networks to encourage healthier choices, helping individuals identify their passions, talents, and values while fostering a sense of purpose. It aims to facilitate the inclusion of socio-economically vulnerable populations and neighborhoods by providing a comprehensive holistic approach that addresses key behavioral factors, and empowers communities to improve health and well-being.

Since its pilot program in Albert Lea, Minnesota, the Blue Zone Project has expanded to 58 communities across North America and Hawaii, impacting millions of people, according to its promoters. ⁴ Cities that successfully implement these changes received a “Blue Zone Community” certification, which shows improved health outcomes, lower costs, and increased civic pride—all of which support economic growth.

As an organization that promotes the lifestyles and environment of the world’s longest-living people, Blue Zones LLC has evolved into a lifestyle brand that offers numerous branded products and services designed to enable people to live longer and better by improving their environment. To reinforce business interests, the use of the term “Blue Zones” is restricted across various goods and services. However, as the term is widely used, Blue Zones LLC has not been able to monopolize it, or to prevent its use in scientific literature.

Nevertheless, the Blue Zones Projects have faced scrutiny. Carter ⁶² described these projects as public-private initiatives that focus on self-responsibility. From a neoliberal perspective, such initiatives may overlook health disparities related to poverty, unemployment, education, and other social factors. Furthermore, they lack direct connections to the health care sector but focus on promoting lifestyle without consistently providing medical evidence.

Regarding the Iowa BZ project, Carter noted inequalities in access to potential benefits, while in Cedar Rapids, a BZ certified in 2016, local authorities decided not to renew their contract due to excessive costs. Recently, criticism has focused on the commercialization of the concept. Dana Smith ⁷ notes that over the past 20 years, the BZ brand has created books, a Netflix series, and a multi-million-dollar city certification program, while the original goal of engaging socio-economically vulnerable populations has been largely overlooked.

In Europe, the implementation of BZ principles began in the Netherlands in 2017, with the concept of “Positive Health” aligning closely with BZ characteristics. ⁶³ In April 2018, the Centre of Expertise Healthwise (University of Groningen) organized the first Healthwise Lustrum Conference, titled “Man-Made Blue Zones: Healthy Ageing Together,” in collaboration with the Healthy Aging Network Northern Netherlands. ⁶⁴

The “Living Blue Zone” concept became tangible with the first urban Blue Zone in Cartesiusdriehoek, Utrecht, which includes 2600 homes, a central park, and various well-being facilities. The first inhabitants of the “Nicoya Block” celebrated their opening launch in May 2025. ⁶⁵ In June 2024, the first Blue Zone Festival in Zwolle brought together architects, scientists, and urban planners to discuss healthy living environments. Inspired by BZs, themes under discussion included housing, social interaction, exercise, nutrition, and well-being. The second edition took place in May 2025 in Amersfoort. ⁶⁶

Conclusion

Originally a purely demographic concept introduced in 2000, the BZ has gained popularity since 2005, following an article in National Geographic. ² Since then, interest has grown, but along two different paths. While researchers have pursued their rigorous age validation methodology recently applied to Martinique and South Galicia, and studied factors that contribute to exceptional longevity, Blue Zones LLC, the company that initiated the Blue Zone projects in the US, has moved in a lucrative business direction by branding various services and goods labeled as BZ products.

However, this increased recognition and popularity have also triggered criticism, some of which questioned the reliability of the data used to define BZs or challenged deeply rooted assumptions that claim exceptional longevity is unlikely in largely illiterate or economically underdeveloped populations.

Criticism is an integral part of the scientific process, and should be welcomed. The age validation process is never final, even if the outcome appears to be generally favorable. The limitations concerning the data used are clearly presented in the present contribution, and some cases of errors are presented in supplemental documents. The results of age validation based on methodology described above, and the exceptionally high number of people reaching 100 years of age in BZs allow us to conclude with reasonable confidence that these BZs of exceptional longevity do indeed exist, even if there are indications that this exceptionality is transient and may be transitory. Given the rapid aging of populations in many modern societies, BZs should be considered as a valuable model for promoting longer, healthier, and happier lives.

Appendix.

Annex 1.

List of Alleged and Confirmed BZ with Details on the Different Steps of the Validation Process by Year of Initial Information.

Alleged areas	Information on an alleged BZ	Preliminary investigation	First visit on the field	Meeting centenrians	Checking administrative registers	Age validation completed	Number of births accounted	Conclusion	Notes
Italy Sardinia	1999	x	x	x	x	x	x	BZ	1
Greece Crete	2000	x	x	x					2
Japan Okinawa	2001	x	x	x				BZ	3
Spain Menorca	2002	x	x	x	x				2
Georgia	2002	x	x	x					2
Costa Rica Nicoya	2005	x	x	x	x	x		BZ	4
Ecuador Vilcabamba	2006	x							2
South Korea Sunchang	2006	x	x	x					2
Norway Dalh Valley	2007	x	x	x					2
Cuba	2007	x	x	x					2
Greece Ikaria	2008	x	x	x	x	x		BZ	4
Greece Rhodos	2008	x	x	x					2
USA Loma Linda	2008	x	x						2
Cyprus	2008	x	x	x					2
Mauritius Rodrigues	2010	x	x	x					2
China Bama Valley	2011	x	x	x					2
Italy Sicily	2012	x	x	x	x	x	x	In progress	5
China Shangri la	2015	x	x						2
Italy Cilento	2016	x	x						2
UK Guernesey	2017	x	x						2
Barbados	2018	x	x	x					2
Denmark Langeland	2019	x	x	x	x				2
France Martinique	2019	x	x	x	x	x	x	BZ	1
France Guadeloupe	2019	x							6
Chile Los Lagos	2024	x	x	x					2
Spain Galicia	2024	x	x	x	x	x		In progress	5
Peru	2025	x							6
Brazil Veranópolis	2025	x							6
NOTES	1	The complete validation process was successful
	2	In these areas, the validation process was not successful
	3	The exceptional longevity in Okinawa have been demonstrated by ORCLS (https:\\www.orcls.org)
	4	In both Nicoya and Ikaria, the births were not accounted, and the exceptional longevity was proved on the base of statistical data
	5	In both Sicily and Galicia, the validation of an alleged BZ is still in progress
	6	In both Brazil and Peru, the validation process has not yet started

Annex 2.

Values of ELI for Each Generation of Newborns and Centenarians Born Between 1907 and 1920 Displayed in Table 1.

	Sardinian BZ	Italy	Martinique	France	Galicia 34	Spain
1907	470	551	1412	757	606
1908	394	570	1153	828	599	522
1909	852	656	1403	882	646	578
1910	964	693	1173	955	398	640
1911	1260	760	1580	1005	683	692
1912	1747	799	1876	1090	1034	744
1913	1293	817	1954	1173	793	796
1914	1409	865	1974	1308	293	852
1915	1369	844	2179	1296	1392	814
1916	1673	853	2120	1294	1280	891
1917	1097	911	2879	1354	1007	951
1918	1576	882	2630	1417	1251	979
1919	2668	991	2398	1477	1444	1102
1920	2083	1054	2439	1666	2106	1254

ELI, the extreme longevity index, is the probability for a newborn to become centenarian expressed per 100,000 newborns. It is calculated by dividing the number of centenarians born in the area by the corresponding number of newborns, the ratio being multiplied by 100,000.

ORCID iDs

Michel Poulain https://orcid.org/0000-0003-2642-7523

Anne Herm https://orcid.org/0000-0003-1716-5453