Why do certain areas of the world seem to have such large concentrations of people who live past 110 years old? According to a working paper, the answer may be bad record-keeping, Kelsey Piper writes for Vox.
Why supercentenarians may not be as common as we think
Researchers have long sought to identify why some people, known as supercentenarians, live to 110 years old and beyond. They've even zeroed in on a few regions of the world—such as Okinawa, Japan, and Sardinia, Italy—that are home to a disproportionate number of supercentenarians, speculating that there might be something special about these regions' diets or climate.
But a paper recently released on bioRxiv, an open access site for prepublication biology papers, offers a different explanation: Maybe those regions just do a poor job of recording when their residents were truly born.
To explore this possibility, the paper's author, Saul Justin Newman from the Biological Data Science Institute at Australian National University, began by looking at official record-keeping in the United States.
Until the early 20th century, many states didn't maintain reliable records of births, Piper writes—and accurate birth certificates were introduced at different times in different states. By examining the variations in state-level policies, Newman discovered that "the state-specific introduction of birth certificates is associated with a 69-82% fall in the number of supercentenarian records."
In other words, seven or eight out of every 10 people who were believed to be supercentenarians were actually younger than 110 years old—whether because an individual lost track of their age, accidentally double-counted some years, were told they were born in the wrong year, or deliberately misrepresented their age, Piper writes.
Next, Newman turned his attention to the supercentenarian "hot spots" in Italy and Japan. He found that, in each case, the areas with the most supercentenarians had high overall crime rates and low life expectancy.
Newman suggests that it's unlikely that living in a high-crime, low-life-expectancy area makes someone likelier to reach age 110. Rather, a more likely explanation is that these areas have poor official record-keeping—making it easier for supposed supercentenarians to misremember or misrepresent their age.
One lucrative reason why someone might lie about their age, according to Newman, is pension fraud. For example, an individual might claim a dead person is actually alive in order to continue receiving their pension benefits, or someone may take on the identity of their parent or older sibling to obtain their benefits, Piper writes.
What does this mean for research into supercentenarians?
Overall, Newman concludes that "[r]emarkable age attainment is predicted by indicators of error and fraud," rather than being correlated with access to high-quality medical care or a healthy population of elderly people.
"As a result, these findings raise serious questions about the validity of an extensive body of research based on the remarkable reported ages of populations and individuals," Newman writes.
The paper, which has yet to undergo peer review, also "illustrate[s] an interesting statistical phenomenon," Piper writes. When looking for something that's very rare, a data set is likely to include a large number of false positives. "For example, if you're looking for a disease that affects only one in a million people, and your test for the disease is 99.99% accurate, then it'll turn up 100 false positive for every true positive," Piper writes.
Similarly, while the majority of people are not likely to engage in fraud or identity theft, "if one in 1,000 people would do that, then fraudulent supercentenarians will be more common than bona fide supercentenarians," Piper writes (Piper, Vox, 8/8).