Being male, stress, lifestyle all increase biological age
A 'biological age' score predicts that being male, overweight, a smoker and having depression all contribute to biological aging, a new study finds.
Biological ageing or functional ageing is the
progressive decline in physiological ability to meet demands and is influenced
by factors such as chronological age, nutrition, stress, exercise, and sleep
besides genetics.
Aging can be measured in different ways. While
chronological age is measured by date of birth, scientists have developed a
range of measurements to determine our biological age. These include measuring
the length of telomeres (little caps on the end of our chromosomes that shorten
as we grow older), chemical changes to our DNA (epigenetics), and changes to
the proteins and metabolites in our bodies (proteomic and metabolomic
measures).
Although studies have linked these individual
measurements to physical and mental health, it is not known whether they
influence each other—a or whether they have a cumulative effect on our overall
well being as we age. This new research, published in eLife, is the first to
combine these individual measurements of biological age and show how they link
with mental and physical health.
"To develop a better understanding of the
mechanisms underlying biological aging, we wanted to examine how indicators of
biological aging relate to each other, how they link to determinants of
physical and mental health, and whether a combined biological clock, made up of
all age indicators is a better predictor of health," explains lead author
Rick Jansen, Assistant Professor at the Department of Psychiatry, Amsterdam
UMC.
The team used blood samples from nearly 3,000
people taking part in the Netherlands Study of Depression and Anxiety. They
applied computer modelling to create individual biological aging indicators
based on five commonly used measurements: telomere length, epigenetics, gene
levels, metabolites and proteomics. The five indicators were then linked back
to different factors such as sex, lifestyle factors and known physical and
mental disorders such as depression.
Of the five biological aging indicators, only
three were found to significantly interact in individuals, such that an
increase in one indicator also paralleled an increase in the other. There were
many overlapping and distinct links between particular aging indicators and
specific lifestyle factors or diseases. But being male, having a high body mass
index (BMI), smoking and having metabolic syndrome were most consistently
linked with more advanced biological aging.
The team also confirmed that depression was
linked to more advanced aging measured by epigenetics, gene levels and
proteomics. This suggests that biological aging is linked to both mental and
physical health.
When they combined all five measures into a
composite score of biological age, they found more and stronger associations for
the composite score than for each individual biological aging indicator. This
composite score had greater associations with BMI, sex, smoking, depression
severity and metabolic syndrome, highlighting the interplay between different
systems on cumulative biological aging.