It's not your imagination; some people really do age more slowly than others.
Duke researchers have analyzed a long-running study of a thousand people born the same year in Dunedin, New Zealand.
Dan Belsky is an Assistant Professor at Duke University School of Medicine and Social Science Research Institute, and led a team of researchers with members from the U.S, U.K., Israel and New Zealand. Their analysis found that 18 biological measures can help determine whether people are aging faster or slower than their peers.
Belsky and his team looked at health factors including people's:
- kidney
- liver
- cardiovascular health
- metabolism
- appearance
Belsky said some subjects were physically aging two-years at a time, while others were biologically younger than their real age.
"When they're all 38 years old chronologically, some are biologically as young as 30 and others are biologically as old as 60," Belsky said. "We don't know why that is yet. We're now doing the research to figure that out."
Belsky added that this information could be useful for sociologists and public health researchers as a tool to quantify how populations are aging in certain places and then change the area's environmental factors.
Despite possible improvements to people's environment, Belksy said it's probably inevitable that health deteriorates with age.
"I think the the question is whether things can fall apart more slowly than they are now. Whether we can make more of the population look like the slowest aging participants in the Dunedin Study."
Belsky said more research will need to be done to understand aging across demographics and environmental factors before the proper tools can be developed to determine biological age. The team's findings can be found in this week's issue of the Proceedings of the National Academy of Sciences.