Ever wonder why you got your first wrinkles years before your friends, even though you're the same age?
The pace of aging differs from person to person, according to a study published last week in the journal Proceedings of the National Academy of Sciences.
The study is one of the first to quantify aging in young people, and it suggests that aging research, especially on treatments to slow aging, can and should be done in younger populations.
Most studies of aging focus on older adults with chronic diseases of aging, such as arthritis, heart disease, dementia, says Daniel Belsky, an aging researcher at Duke University in North Carolina who led the study. "If we want to intervene most effectively to prevent age-related diseases, we may need to start earlier in life."
Belsky and colleagues at five universities studied a group of 954 individuals in New Zealand who had been tracked since birth as part of a long-term study of human health and development.
When the participants turned 38 in 2010-11, Belsky's team collected blood from each and measured a slew of physical characteristics, such as lung function, dental health. To assess how the participants' bodies had changed over time, the team compared the most recent information to physical exams and blood samples done when the participants were age 26 and 32.
Looking at 18 different biological markers — from kidney function to immune-system activity — the researchers saw a huge range in the pace of aging. While many aged the expected one biological year per chronological year, others aged zero years per year, actually staying younger than their chronological age. "For them, time was standing still," says Belsky.
There were also those who aged faster than normal, as quickly as three years per chronological year. To find out whether that speedy aging affected health, the researchers conducted a series of physical and cognitive tests, such as balance, coordination, and memory, on each of the participants.
Compared to those who had slow or no biological aging, those who aged quickly were physically less strong, had worse balance and motor coordination, and had decreased IQ scores compared to their youth. They also looked older to unbiased observers.
In other words, faster agers showed their age.
The big question is why some people age faster than others. If researchers can figure that out, Belsky says, they may be able to determine how to slow aging as soon as it starts.