Humans age at remarkably different rates — and the process begins much earlier than one might think, according to a new study of 954 people tracked since birth.
At the tender age of 38, the "biological age" of the study volunteers ranged from 28 to 61 years old.
FOR THE RECORD
This post has been corrected to reflect that the Dunedin study was conducted in New Zealand, and that 954 subjects participated.
Fast-aging study members showed greater declines in IQ, increased sign of stroke and dementia risk, poorer balance, weaker fine-motor control and diminished strength.
The fast-agers knew they were getting old prematurely — they were more likely to report poor health. Their decline was evident to others as well — independent observers judged them to look older than slow-agers, according to a reporthttp://www.pnas.org/content/early/2015/07/01/1506264112 this week in the Proceedings of the National Academy of Sciences.
The research team, led by Daniel W. Belsky and Terrie E. Moffitt of Duke University in North Carolina, focused on what aging looks like in the third and fourth decades of life. The study participantshttp://dunedinstudy.otago.ac.nz/studies/assessment-phases/the-study-members were all born in Dunedin, New Zealand, in 1972 and 1973.
As members of the cohort reached 26, and again at ages 32 and 38, the researchers measured their metabolic and immune function and the state of their gums, hearts, lungs, blood vessels, kidneys and livers.
They also recorded such readily measurable items as body mass index and waist-to-hip ratio, and more esoteric items such as the length of certain telomeres — the shoestring-like ends of chromosomes that fray with age.
The researchers were able to detect heavy signs of aging in some, and age's light touch upon others. In all, the researchers found that 18 biomarkers likely provide enough information to judge a person's biological age well in advance of the onset of any age-related diseases.
Some measures of aging can be reversed with lifestyle changes. But having a way to recognize accelerating aging in younger adults may cast light on some of its earliest influences, including genes, prenatal circumstances, childhood experiences and socioeconomic influences.