The cells of people who
have had depression may age more quickly, a new study suggests.
Dutch researchers compared
cell structures called telomeres in more than 2 400 people with and without
Like the plastic tips at
the ends of shoelaces, telomeres cap the ends of chromosomes to protect the
cell's DNA from damage. Telomeres get a bit shorter each time a cell divides,
so they are useful markers for ageing.
The researchers found that
the telomeres of people who had ever been depressed were significantly shorter – about 83 to 84 base pairs of DNA shorter, on average – than those of people
who had never suffered from depression.
The results remained even
after researchers accounted for a host of lifestyle factors that can also
damage DNA, such as heavy drinking and cigarette smoking.
Since people naturally lose
about 14 to 20 base pairs of DNA in the telomeres each year, the researchers
said the difference represents about four to six years of advanced ageing.
The study showed only an
association between depression and shorter telomeres, and didn't prove a
cause-and-effect link. The researchers said they aren't entirely sure what the
shorter telomeres might mean in depression.
On one hand, study author
Josine Verhoeven said, it could be that having shorter telomeres somehow sets a
person up for mental troubles. But it's more likely that depression causes
damage that leaves traces even at the cellular level, she said.
Depression disrupts many systems
Depression is known to
disrupt many physical systems. It alters hormones, suppresses the immune
function and changes how nerves work. People with a history of depression have
greater risks for diseases of ageing, such as heart disease, type 2 diabetes,
dementia and cancer.
"Results like ours
suggest that psychological distress, as experienced by depressed persons, has a
large, detrimental impact on the wear and tear of a person's body, resulting in
accelerated biological ageing," said Verhoeven, a doctoral researcher at VU
University Medical Centre in Amsterdam.
The study was published
online in the journal Molecular Psychiatry.
One expert said the study
is significant in the number of people it involved.
"The strength of this
report is its size," said Etienne Sibellie, an associate professor of
psychiatry at the University of Pittsburgh. He is studying how depression ages
Sibellie said previous
research on the same question had mixed results – probably because the studies
were too limited to pick up the effect, which is small and varies from person
"It's a small effect,
but it's real," he said.
The next question science
needs to answer, Sibellie said, is whether telomere shortening really matters
and if reversing it could improve health. Other studies have shown that a
healthier diet, exercise and measures to control stress may lengthen telomeres.
"It's just not known
whether it has an impact on cell function," he said. "If that's the
case, it has potential therapeutic importance."
Head to the US Centres for
Disease Control and Prevention for more on healthy ageing.