Blue Zones: FACT SHEET

Blue zones are geographically defined areas with some of the healthiest, longest-living populations in the world. Sardinia was the first identified blue zones region in 1999, verified by an 18-year collaboration demonstrating that the island’s longevity was genuine. Since 2005, the concept of Blue Zones has extended to other regions of the globe. Using strict demographic criteria, long-lived communities have been validated in five locations: Okinawa, Japan; Sardinia, Italy; Ikaria, Greece; Nicoya, Costa Rica; and Loma Linda, California.  

Numerous peer-reviewed scientific papers have validated the demographic origins of blue zones. Recent criticism has been raised about the accuracy of the ages of centenarians within these communities. However, the findings below – based on the complex research methodology of Giovanni Mario Pes, a longevity researcher and Associate Professor at the University of Sassari – prove that the principles discovered in these areas are not only valid but still hold true more than a quarter-century later. 

 

How does the age verification process work?

The age verification process involves finding areas with high numbers of long-living people using public demographic data, counting the number of people born in those areas sorted by sex and birth year, identifying people of a certain age, and calculating the ratio of these people to the total number of births during the same period.

 

• Sardinia: The age validation process used written records, including civil status databases, ecclesiastical archives, and genealogical reconstructions. At least two independent data sources must be verified, making errors in age very unlikely. 
• Nicoya: Age validation was conducted using detailed electoral registers and civil status data dating back to 1949 and 1970, respectively, excluding individuals with unverifiable birth records. Each person was assigned a unique identification number at birth or naturalization, which appears on their identity card or cédula, and is impossible to tamper with. Additionally, in Nicoya, civil status data can be compared with those available in the ecclesiastical archives. 
• Ikaria: The age validation involved comparing mortality statistics from Greek central institutes with data from the ‘dimotologion,’ an administrative registry. Additionally, exhaustive interviews were conducted with residents aged 90 and above, using detailed questions about demographic events and relatives’ ages.
• Okinawa: Age validation sources included Japan’s National Directory of the Elderly, official population censuses, and regional life tables. Despite WWII bombings destroying many birth records, preserved and reconstructed documents allowed age validation for 94.2% of a sample of centenarians.

• Loma Linda: Subjects were identified and enrolled in a longitudinal study between 1976 and 1988 via church directories. Health was verified through hospital data and deaths were verified through computer matching to California state death tapes until 1979, when the National Death Index became available.

 

The truth behind seven blue zones misconceptions

The recent media articles stem from an opinion paper written by a critic with no demographic training. It was not, as covered by some media outlets, a new study or research. Below is extensive research that addresses these misconceptions, which are academically misleading and deeply flawed.

 

Record-Keeping Misconceptions:

1. Myth: The evidence and databases from organizations such as the Gerontology Research Group (GRG), which point to an exceptional proportion of centenarians and supercentenarians in the blue zones, are flawed.

Truth: While it is true that some such databases may include errors, this statement inaccurately implies that Blue Zones research does not include rigorous age verification requirements and statistical analysis. Blue Zones has firmly established and refuted such discrepancies. Avoiding the distinction between partially validated databases, such as GRG, and scientific organizations, like the International Database on Longevity (IDL), is scientific misconduct.

 

1. Myth: Very few centenarians in the blue zones have original birth certificates, and most have no reported birth documents of any kind. 

Truth: The blue zones regions are NOT areas with supercentenarians. Newman’s reasoning behind this false equivalency states that only about 6% of supercentenarians have original birth certificates, and 74% have no reported birth documents. However, he cites places like Manchester, Tyneside, and Liverpool. These places are full of false supercentenarians but are not blue zones regions.

 

1. Myth: Birthdates and records for several supercentenarians in Japan and the U.S. databases exhibit “age heaping” patterns or reporting ages in groups divisible by 2, 5, or 10.

Truth: Again, the blue zones regions are NOT areas with supercentenarians. Within identified blue zones, age verification methods rule out similar mistakes and age-heaping patterns. A study assessing age heaping in centenarians from Okinawa used several techniques, such as the mortality risk ratio and Whipple’s Index for centenarians. They found no evidence of age heaping in the Okinawan centenarian data. Verified records, not self-reported ages, confirm true blue zones regions. 

 

1. Myth: Blue zones correspond to areas with socioeconomic indicators of abnormally high prevalence of unhealthy factors, such as high illiteracy, poverty, and crime rate, indicating a primary role of fraud and error in generating age records and calling into question the validity of records for such individuals.

Truth: The claim that low income predicts around 40% of the variation in supercentenarian abundance might be generally valid, but it does not apply to certified blue zones areas. In Sardinia, researchers hypothesized that the low trend in early mortality found in their study is explained not by economic development but rather by the positive effect of prolonged breastfeeding and limited participation of women in external works. Additional studies on regional data and selected villages confirmed this trend of low early mortality.

 

Lifestyle Misconceptions:

1. Myth: Blue zones are known to be lower-income, high-poverty areas, which calls into question the well-established “social gradient theory.” It posits that individuals with lower socioeconomic status (SES) experience poorer health outcomes and shorter lifespans compared to those with higher SES. 

Truth: It is true that a certain degree of economic underdevelopment has historically characterized blue zones. However, the cases of Okinawa and Sardinia demonstrate that the highest longevity is observed where the modernization process began later and developed more slowly, not necessarily due to SES.

 

1. Myth: The Blue Zones research falsely implies that poverty, a condition generally linked to worse health outcomes, is positively associated with a higher probability of reaching an extreme age.

Truth: Although some blue zones, such as Nicoya and Sardinia, have traditionally been considered lower-income regions, it does not necessarily equate to poor health. 

 

1. Myth: The anomalously high percentage of smokers (up to 17-50%) and alcohol consumption in some areas populated by centenarians raises doubts about the authenticity of the longevity phenomenon.

Truth: In a paper on nonagenarians – those aged 90-99 – from Sardinia, the percentage of current smokers was 1% in males and zero percent in females. In longevity surveys outside the blue zones, the duration of the smoking habit is not always specified. This lack of data does not correlate with longevity. Moreover, there is no evidence that long-lived people drink alcohol or smoke excessively in the blue zones regions. In Sardinia and Ikaria, moderate drinkers were predicted to be protected from cardiovascular diseases due to the polyphenol content in red wine. Notably, Sardinians consumed Cannonau wine on a daily basis, which has two to three times the levels of flavonoids as other wines – and one flavonoid in this wine, procyanidin, has been shown to help maintain vascular elasticity and normal blood pressure. The concurrent adoption of the Mediterranean diet could bring other positive effects.