Why do some people
seem to age more rapidly than others? Does accelerated raging exist? Why do some 40-year-olds look 60 and yet
others look 35? What is the difference between actual (chronological) age and
biological age? What is the pace at which we age?
A report in the
Proceedings of the National Academy of Sciences (PNAS) on July 1, 2015,
documented the work of researchers at Duke University in America. Researchers
tracked aging traits to determine what causes the pace of aging. They wanted to
determine whether people do age at different paces, when does this start to
occur, and why.
The study –
Quantification of biological aging in young adults – led by Daniel Belsky,
assistant professor of medicine at the Duke University School of Medicine’s
division of geriatrics, assessed people born within a year of each other over
12 years as they aged. Researchers followed a group of 954 people from the same
town (Dunedin) in New Zealand who were all born in 1972-1973. The scientists
looked at 18 different aging-related traits at different ages – when the
participants were 26 years old, 32 years old, and 38 years old. The traits
measured were markers for physical age, meaning that those who aged faster also
looked older (according to unbiased assessments by random people looking at
photographs of the study participants).
Most studies on aging
start with people in their 50s and older. This study looked at a younger cohort.
Each participant agreed to be ‘tracked’ over the years against 18 different
traits, including weight (body mass index – BMI), blood pressure, cholesterol,
lung function, kidney function, dental (gum) health, inflammation, and the
integrity of their DNA. Based on these scores, researchers calculated a
biological age for each volunteer when they were 26 years old. They compared
these biological ages against their physical age – chronological agee – at 26,
32, and 38 to calculate their pace of aging.
The findings showed
that indeed people do have varying paces at which their bodies age, and that some showed signs of accelerated aging. Most participants’
biological age was within a few years of their chronological age. However, some
had a huge difference between their biological age and their chronological age
– at 38 years, the biological ages ranged from late-20s to nearly 60. Professor
Terrie Moffitt said some volunteers looked ‘lacking in vitality.’ While some
people seemed to stop aging in the 12-year period, others were gaining nearly 3
years of biological age for each year of the study.
Researchers
administered that same tests of balance, thinking (mental agility), and strength
(physical grip) that gerontologists give to aging (older) adults. They found
that people who looked almost 60 tended to do worse in tests of brain function
and physical strength.
Researchers said it
was unexpected to find such differences so early in the volunteers’ lives, but
this would provide relevant information for further studying the pace at which we age. It is the first
step to detect factors that influence the rate or pace of aging. Belsky said
that 80% of the factors that were influencing aging were not genetic –
therefore they were within people’s control.
The next step is to
identify the causes of accelerated aging so that people can slow it down. Belsky
said the research team would continue to follow the study group and re-evaluate
them again when they are 45 years old.
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