Posts Tagged ‘blue zones’
human longevity stuff: Blue Zones
The other day, I was talking to friends about human health and longevity and the claim, in a book I use for teaching English to NESB adults, that Okinawans are known for their longevity and that this is likely due to self-sufficiency, physical activity, diet and regular human interaction. While this was generally accepted in our discussion, I received some mild push-back to the effect that this had been exaggerated somewhat, and that the concept of ‘blue zones’, which I’d never heard of, had been largely debunked. So, let me look into this.
A December 2025 article in The Gerontologist, also published in the National Library of Medicine, entitled ‘The validity of Blue Zones demography: a response to critiques’, and which has two named authors, opens with these remarks in its abstract:
Blue Zones are geographically and temporally defined areas with a history of disproportionately high concentrations of nonagenarians and centenarians. Nearly two decades ago, these zones gained international attention when the Blue Zone term was introduced in seminal articles published in Experimental Gerontology and National Geographic. Since then, numerous scientific papers have extracted valuable insights into human health from investigating the long-lived people who live there. However recently, validity of the ages of people living in the Blue Zones has been questioned. Here, we address these concerns by describing in detail the age validation process undertaken in Blue Zones and comparing it to the prevailing standards in gerontological demography.
The abstract goes on to point out what is fairly obvious, that ‘most self-reported claims of exceptional longevity are false’, and of course I remember reading in the Bible about 969-year-old Methuselah and his remarkable rellies. Well, at least their god is real, en it? Anyway, the abstract ends with the claim that ‘cross-checking multiple independent documentary sources’ has effectively minimised or eliminated ‘errors due to fraud, honest mistakes, poor memory, or identity switches, especially between homonymous [identically – or near identically-named] siblings’. And this, it’s claimed, leaves us with Blue Zones that are ‘valid and reliable’.
Reading on, the paper states that Japan has been accurately found to be the longest-lived country for at least the last century, but more importantly for this little essay, it highlights the work of a 19th century pioneering demographer and folklorist (he apparently coined the term ‘folklore’), William Thoms, who proposed these steps for verifying longevity claims:
(i) search for official birth records; (ii) check the records for other individuals with the same name; (iii) corroborate the birth record with additional forms of evidence; and (iv) if the person is still alive, verify as much as possible by quizzing the person about things such as public events that can be cross-checked with additional data sources.
These are a start; in the 21st century we generally have more effective record-keeping, at least in the ‘first world’. In those countries where, unsurprisingly, records aren’t so well kept, credulous investigators can be duped. This happened when National Geographic sent a Harvard physician, Alexander Leaf, to various soi-disant ‘longevity hotspots’, in Equador, Pakistan and the region now known as Azerbaijan, in the early 1970s. Leaf’s report, apparently, was a monument to credulity, and was soon invalidated by more experienced analysts, but it all eventually led to what became the ‘Blue Zone’ disputes. The term is explained in the Gerontologist article, referenced below.
When one of us … in 1999 presented for the first time data suggesting the existence of exceptionally long-lived communities in the central area of the Mediterranean island of Sardinia, where the proportion of centenarians was demonstrably higher than in the rest of the island (Pes, 1999), most demographers reacted with skepticism. From 2001 to 2019, a collaboration with the Belgian demographer Michel Poulain was able to demonstrate that Sardinian longevity in these areas was genuine. For instance, it was determined that people born in this longevity hotspot between 1880 and 1900 were nearly three times as likely to live to the age of 100 years as Sardinians living outside the area. The area was dubbed a Blue Zone because of the blue marker used to indicate the area on a map. The first scientific article mentioning this term was published in Experimental Gerontology in 2004 (Poulain et al., 2004).
So the Blue Zone concept has been extended to other regions based on careful research (I cannot, of course, confirm this, but the article goes to great lengths to present and justify its methodology – in fact that’s the article’s entire purpose, so all skeptics should read it). Four areas, in particular, have been confirmed, and are ‘generally accepted by the international scientific community’, along with the Blue Zone concept: Okinawa, Japan; Sardinia, Italy; Ikaria, Greece; and Nicoya, in north-western Costa Rica. These regions are separately dealt with in detail in the article, so I would be hard put to provide a summary here. The article also points out that Blue Zones can come and go, or weaken or strengthen, due to immigration, emigration, westernisation or other factors. Okinawa, for example, has recently been in dispute regarding its status due to some of these factors, as has the Nicoya zone.
Finally, I’ll just quote the age verification processes used:
… it requires: (i) identifying potential high-longevity target areas based on public demographic databases; (ii) accurately counting the number of people born in the target area, categorised by sex and year of birth; (iii) identifying and confirming the age, using additional data sources, of individuals who have reached a preset threshold age (e.g., 90 years); and (iv) calculating the ratio of the 90+ population to total births recorded during the same time interval. This ratio reflects the probability of people born in the target area to reach the threshold age. The process is designed to minimise the likelihood of false positives (type I errors) and ensure accurate identification of Blue Zones.
And I’ll just finish by mentioning a few points. The first-described Blue Zone, in Sardinia, as mentioned, doesn’t include the whole island, but ‘six villages located in the hills of a rural region in east central Sardinia called Ogliastra containing about 12,000 people’. The percentage of centenarians there…
was approximately five times as high as the percentage of centenarians throughout Europe and nearly three times the percentage in Sardinia as a whole. Equally surprising, although worldwide there are roughly three times as many female as male centenarians—in the Sardinian Blue Zone there were approximately equal numbers of male and female centenarians (Poulain et al., 2004). Since that original analysis, the proportion of centenarians in this Blue Zone has increased (Poulain & Herm, 2025).
That is really fascinating, as it brings to mind the general question of female longevity in comparison to that of males. Something for another post, perhaps. It also, of course, raises the question of why only one area of Sardinia qualifies as a Blue Zone. No answer is provided or attempted. And, to be fair, the article’s purpose is to validate the existence of Blue Zones, not to explain why they exist.
The Blue Zone in Nicoya, Costa Rica, has, on re-investigation, shrunk to about a quarter of its size compared to earlier studies, but ‘a new Blue Zone had emerged in three provinces in northern Costa Rica near the Nicaraguan border’. The Blue Zone on the mountainous Greek Island of Ikaria, which has a population of about 8,000, has been validated between 2008 and 2009, with details provided. And while there is evidence of false claims regarding centenarians in Japan, the data from Okinawa has been validated.
Of course there is speculation as to why these Blue Zones exist, and why they tend to occur in ‘under-developed’ regions. Often under-developed regions have high crime rates, and lower life expectancies, but more isolated and self-sustaining regions appear not to have experienced these problems. It does seem to be the case that community support and connection, physical activity, as well as some genetic elements as yet uncovered, are an important part of the answer.
Reference