Sure, sometimes people may mistake you for the older sibling when you’re actually the younger one. Or you may wonder why your good friend looks so much older than you when she’s almost a whole year younger than you. Common answers to these little mysteries tend to be genes, diet, (lack of) exercise, or picking up bad habits like smoking. Now, thanks to research published this year in the Proceedings of the National Academy of Sciences, there is proof that shows some people do age faster than others, and it isn’t just a mind trick.
This isn’t an April Fools’ Day prank published a few months late (in fact, the data came from the Dunedin study, which is a longitudinal research project that has studied people since each individual’s birth in 1972 or 1973 through now); this research about people aging studied roughly 1,000 men and women from Dunedin, New Zealand and monitored the individuals’ health for all of those years.
While we won’t go into the whole study, we will tell you what the scientists who conducted the study looked at in order to determine their findings. In this study, scientists from the United States, United Kingdom, New Zealand, and Israel looked at markers that designate chronological age and physical age. Undergraduate students from Duke University were even unbiased contributors, who looked at photos of Dunedin study participants and subsequently guessed the ages of the participants. These undergrads presumed the participants who were aging faster chronologically were the participants who were older physically. And although this was true for a handful of the photos the Duke students examined, it wasn’t always the case.
Still with us? It’s a little garbled, we know, but the assessments done by the Duke undergrads demonstrates that people do indeed age differently than their peers. Just because you both happen to be born within the same year as another person (in this case, 1972-1973), doesn’t mean the younger person chronologically is going to look younger physically. So why do some people age differently, sometimes age faster, than others? Unfortunately, this test didn’t answer why some people are aging faster than others.
It did tell, though, what the group of scientists looked at to determine which participants were aging faster physically than their actual chronological age. The scientists working on this study looked at 18 biological markers from participants of the Dunedin study for signs of aging. Among those biological markers include kidney, lung, liver, and metabolic immune function; as well as HDL cholesterol, dental health, blood vessel condition, telomere length, and cardiorespiratory fitness. The researchers then took the aging results from those biological markers; assigned each participant a “biological age” based on the results, and compared them to similar results from previous studies the participants had taken a part in. Comparing the results from this study to previous results allowed the researchers to see just how quickly each participant was aging and how some were aging differently than others.
Though this newly published research from the Dunedin study doesn’t answer why some people age differently than others, the next study may. The women and men who are a part of the Dunedin study will undergo another series of tests once they turn 45. Until then, you may just have to accept the fact that you look older than your older sibling.
To view the published research in the Proceedings of the National Academy of Sciences, click here. To see a more in-depth analysis on how the researchers concluded their results in this test, read Yahoo’s story on the research.