Exploding the "Blue Zone" myth
What do the world areas of purported "super longevity" really have in common? Poverty, illiteracy and untrustworthy birth and death records
Among the 2024 winners of the IgNobel prize is a researcher who exploded the myth of the “Blue Zones”, and it’s high time someone calls that bullshit. Last year, writing for my Brazilian weekly science column, I criticized the whole concept of the so-called “Blue Zones”, then promoted in a Netflix “documercial” series: the idea that certain regions of the planet, supposedly inhabited by a disproportionate number of people over 100 years old, had unveiled the “secret of supercentenarian life.”
My criticism was based on the naive interpretation of the apparent correlation between certain habits (eating honey, taking long walks) and the supposed longevity. This is just the plain old “survival bias” fallacy: seeing who has succeeded in some activity and trying to “reverse-engineer” the process that led to that success.
It sounds like pure common sense, but it fails to adopt proper controls: just because two or three billionaires wake up at four in the morning doesn’t mean waking up early makes someone rich – ask bus drivers and street cleaners. “Recipes for success” (or “longevity”) only live up to the name if we know that there is a significant proportion of successful people within the total universe of those who adopt them, and more: that this proportion also significantly exceeds the success rate of those who do not follow any of the “recipes” recommendations.
What if, despite the few billionaires who rise before the sun, in fact 99% of the others sleep until noon?
The work awarded with the Ig Nobel Prize, authored by demographer Saul Justin Newman from University College London, went beyond this logical critique; Newman sought other “common factors” present in the supposed high-longevity zones and discovered a strong prevalence of what he called “anti-health” factors: poverty, misery, high unemployment, high illiteracy rates, low average life expectancy, high crime rates – and, crucially, the absence of reliable birth and death records.
In the United States, the biggest “predictor” of the prevalence of supercentenarians (people over 100 years old) in a population is the absence of birth certificates in their states of birth during the early 20th century.
“I’ve tracked down 80% of the people aged over 110 in the world (the other 20% are from countries you can’t meaningfully analyse). Of those, almost none have a birth certificate. In the US there are over 500 of these people; seven have a birth certificate. Even worse, only about 10% have a death certificate”, Newman said in an interview with The Conversation, after receiving the Ig Nobel.
Newman documents registration errors in several other “blue zone” hotspots, such as Costa Rica (“in 2008, 42% of Costa Rican 99+ year olds were revealed to have ‘mis-stated’ their ages in the 2000 census”); and “in 2010, over 230,000 Japanese centenarians were discovered to be missing, imaginary, clerical errors, or dead.” In 2012, Greece determined that 72% of its centenarians had, in fact, already died – a likely indication of pension fraud.
The researcher advances the thesis that not only is the marketing of blue zones – which involves tourism, the trade of “natural” products from these areas, or “inspired” by them, along with books, courses, television programs, etc. – lacking a foundation, but that all demographic research on extreme longevity is based on contaminated data: that there are strong indications of fraud, lies, mistakes or deception by a significant number of those who claim to be supercentenarians.
He cites a study conducted in the United States showing that centenarians have body mass index, physical activity rates, smoking, and alcohol consumption rates similar (or worse!) than those of the population that served as control group, which was 35 years younger.
Newman offers four hypotheses to explain how it could be possible to survive from 65 to 100 years old while smoking more, drinking more, eating worse, and doing less physical activity as the years pass: either these behaviors do not cause mortality; or they cause mortality, but the lost lives are “compensated” in the statistics by clerical errors in age records; or centenarians are indeed heavier drinkers and smokers; or older drunkards and smokers lie about their age.
The author provides a hypothetical example to illustrate how a small error (or fraud) rate in age records can, over time, generate a spurious overpopulation of supercentenarians. Imagine that a 50-year-old man decides to lie and to claim he is 60, perhaps to access some kind of pension benefit.
When most of the people who, at the time the fraud was committed, were actually 60 years old start to die – say, from age 85 onward – our character will still have, in fact, the biological age of 75. If he lives to 95, his official age, recorded in documents, will be 105. Given the small number of supercentenarians, just a few situations like this are enough to distort the statistics – and the places where there is the most incentive for such frauds are exactly those where the dependency on pension benefits, brought on by unemployment and poverty, is greater; alas, the case of most “blue zones.”
“Regions where people most often reach 100-110 years old are the ones where there’s the most pressure to commit pension fraud, and they also have the worst records”, Newman said in the same interview.
Reading Newman’s article and recalling the Netflix series, it occurred to me that the fascination with “blue zones” derives – besides, of course, from the narcissistic desire to stay down on Earth for as long as possible – from a romantic fascination with the lifestyle of “simple folks,” from a poetic and nostalgic view of poverty and rural isolation (which, of course, only those who are not poor and live in urban centers can have). It is a condescending and exploitative form of populism, and a highly profitable one.