When you turn up at your high school reunion and look around, you might notice something. Despite all of you being born within one year of each other, some will almost certainly look younger and some older.
Indeed, a recent study published in the Proceedings of the National Academy of Sciences has confirmed what many have already observed: People do actually age at a different rate – and some of us much more dramatically than others. While most people in the study had a biological age close to the 38 birthdays they’d racked up, some were significantly younger or older, reflected in the state of their organs, metabolism and mental abilities.
The researchers from Duke University followed 1,000 people who were born in the same town in the same year, and checked up on them when they were 26, then 32, and finally when they hit 38 years old. The team used 18 physiological markers of risk for age-related chronic diseases – such as organ function, metabolism, blood pressure, and even the length of their telomeres – to calculate the participant’s biological age, and then compared it with their actual age.
Out of the original group enrolled, 30 died before they had reached 38 due to a range of problems, from diseases such as cancer to accidents or suicide. For the rest of them, they took the data collected over the years for each variable and combined them to determine an individual’s pace of aging.
While many of the participants' biological years matched fairly accurately with how many birthdays they’d had, there were quite a few outliers. One had an impressive biological age of 28, meaning that they’d effectively aged zero years for each birthday, while another had a worrying biological age close to retirement at 61. This means that the individual had aged on average three years for every birthday.
Rather than studying aging in older people, as most studies normally do, the team wanted to specifically look at younger people. “Most studies of aging look at seniors, but if we want to be able to prevent age-related disease, we're going to have to start studying aging in young people,” explained Dan Belsky, lead author of the study.
The researchers didn't control for differences in lifestyle – such as smoking or exercise – and so now the scientists plan on looking back at these other factors in each person’s life to try and tease out what may have contributed to the dramatic differences in the aging process. “As we get older, our risk grows for all kinds of different diseases,” says Belsky. “To prevent multiple diseases simultaneously, aging itself has to be the target. Otherwise, it's a game of whack-a-mole.”