This story was originally written in Portuguese, and published to the website of Revista Questão de Ciência. It appears here with permission.
A sign of the shrinking space for science in the Brazilian press is the lack of attention that this year’s IgNobel Award received – announced on the night of 12 September 2024, there hasn’t been a single prominent mention of it in any of our major newspapers. Which is a shame, because among this year’s winners there is a researcher who exploded a myth that Brazillian journalism had swallowed hook, line, sinker, and dock: the myth of “blue zones” of longevity.
Over a year ago I criticised the concept of “blue zones”: the idea that certain regions of the planet, supposedly inhabited by a disproportionate number of people over 100, could hold the “secret of supercentenarian life.” The idea has even been the theme of a successful documentary released by Netflix.
My criticism was based on the naive interpretation of the apparent correlation between certain habits (such as eating honey, or taking long walks) and supposed longevity. It is the fallacy of survival bias: seeing who has succeeded in some activity and trying to reverse engineer the process that led to their success.
It sounds like pure common sense, but it fails to adopt proper controls: just because two or three billionaires have the habit of waking up at four in the morning, that doesn’t mean that getting up at dawn can make someone get rich – just ask bus drivers or garbage collectors. Such markers of success (or “longevity”) are only reliable if there a significantly increased likelihood of success among the population that adopt them, compared to a significantly lower chance of success among the population who do not. And what if, while there are a few outspoken billionaires who get up before the sun, the rest all sleep until noon, but don’t give interviews about it?
The recent IgNobel-winning study, published in the bioRxiv repository and authored by the demographer Saul Justin Newman, from University College London, went beyond this philosophical criticism; Newman sought other “common factors” present in the supposed zones of high longevity and discovered a strong prevalence of what he called “anti-health” factors: poverty, misery, high unemployment, high rates of illiteracy, low life expectancy, and high crime.
It is worth noting that, like all material available in bioRxiv, Newman’s study did not go through peer review – but neither, of course, have the many books, reports and documentaries that have credulously promoted the cult of the “blue zones”.
In the United States, the largest “predictor” of the prevalence of supercentenaries (people over 100 years) in a population is the absence of birth certificates in the early 20th century. “In total, 82% of supercentenary records in the US are prior to the adoption of birth certificates in their states. When these states have full coverage of birth certificates, the number of supercentenarians falls 82% per year.”
“I’ve tracked 80% of people over 110 in the world (the other 20% are from countries you can’t significantly analyze). Of these, almost none have a birth certificate. In the US, there are more than 500 of these people; seven have birth certificates,” he said in an interview with The Conversation after receiving IgNobel.
Newman documents several clerical errors going on in places that purportedly contain “blue zones”. In Costa Rica, it was found, by 2008, that 42% of the population registered as over 99 years of age had ‘made mistakes’ when declaring their ages in the 2000 census. In 2010, more than 230,000 centenarians from Japan were found to have been fictional, were the product of bureaucratic errors, or were actually already dead. In 2012, Greece determined that 72% of its centenarians had already died – a likely indication of pension fraud.
According to Newman, the marketing of blue zones – including tourism, the trade of “natural” products from these areas or “inspired” by them, plus books, courses, and television programs – lacks scientific basis, but also the demographic research on extreme longevity is based on highly contaminated data: there are strong indications of fraud, lying or deception by a significant part of those who declare themselves supercentenarians.
He cites a study conducted in the US that showed that centenarians have similar (or worse!) body mass index, physical activity rates, smoking and alcohol consumption levels versus the population that served as a basis of comparison, which was 35 years younger. Newman offers four hypotheses to explain how it would be possible to survive from the age of 65 to 100 by smoking more, drinking more, eating worse, and doing less physical activity each year: 1/ either these behaviors do not cause mortality, or 2/ they cause mortality, but the lives lost are “compensated” in the published statistics by bureaucratic errors in the age records, or 3/ the centenarians are actually more likely to drink and smoke more, or 4/ that older drinkers and smokers lie about their age.
The author gives a hypothetical example to show 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, saying he is 60, perhaps to claim some kind of social security benefit. When other people who were actually 60 at the time of the fraud began to die – say, from the age of 85 – 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, only a few of such situations are enough to distort statistics – and the places where there is more incentive for such fraud are exactly those where the dependence on social security benefits due to poverty is greater, which is 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 recordkeeping,” explained Newman.
Reading Newman’s article and recalling the Netflix series, it occurred to me that the allure of the “blue zones” derives – among other things – from a romantic fascination with the way of life of “simple people”, from a lyrical view of the supposed purifying merits of poverty, rustic life and rural isolation (views that only held, of course, by those who are not poor, but live in comfort in urban areas). It is a condescending populism converted into the most crass commercialism.
