This is an excellent study that polices up a lot of implied
conjecture that has been already well accepted. The bonus however is
that it is only in the late stage that shortened telomere length is
associated with an increased death risk.
With our developing capacity to replace tissue with stem cells that
turn the biological clock back to zero, the possibility arises that
extended life is completely plausible. In fact, right now it is a
certainty.
In the meantime slowing telomere loss is good and telomere
restoration is better. Efforts in those directions are available at
excessive cost, but you get the idea. This will all be common
knowledge and also common practice in about a decade.
Significant
relationship between mortality and telomere length discovered
A team of researchers
at Kaiser Permanente and the University of California, San Francisco
(UCSF) has identified a significant relationship between mortality
and the length of telomeres, the stretches of DNA that protect the
ends of chromosomes, according to a presentation on Nov. 8 at the
American Society of Human Genetics 2012 meeting in San Francisco.
While a reduction in
telomere length is regarded as a biomarker of aging, scientists have
not yet determined whether it plays a direct causal role in
aging-related health changes and mortality or is just a sign of
aging.
In their prospective
study of 100,000 multi-ethnic individuals whose average age was 63
years, the researchers determined that an association between
telomere length and mortality existed and persisted even after the
data were adjusted for such demographic and behavioral factors as
education, smoking and alcohol consumption, said Catherine Schaefer,
Ph.D., director of the Kaiser Permanente (KP) Research Program on
Genes, Environment and Health (RPGEH).
Dr. Schaefer and Neil
Risch, Ph.D., director of the UCSF Institute for Human Genetics, are
principal investigators of the Genetic Epidemiology Research Study on
Adult Health and Aging (GERA). UCSF professor and Nobel laureate
Elizabeth Blackburn, Ph.D., led the research on telomere length
measurement.
The telomere research,
part of the GERA project, has genotyped over 675,000 markers of
100,000 KP Northern California patients and linked them with health
data from their electronic medical records. To obtain DNA for
genotyping and telomere measurement, the researchers collected saliva
samples from the patients, who volunteered for the project and
provided scientists with access to their electronic medical records.
Two years prior to
the saliva collection, the researchers conducted a detailed survey of
the patients' demographic and behavioral factors, providing a unique
opportunity to address questions of telomere epidemiology and aging.
"With these data,
we examined demographic relationships with telomere length,
behavioral influences and relationship of telomere length with all
causes of mortality following sample collection," said Dr.
Schaefer. "Although we found that shorter-than-average telomeres
were prospectively associated with mortality, only those with the
shortest telomeres were at increased risk of death."
Dr. Risch added,
"While this could indicate a direct effect of telomere length on
health, it will also be important to examine the extent of
pre-existing diseases in these individuals to understand their
possible role in the biological connection between telomere length
and longevity."
Dr. Risch said that he
and the other scientists expected to and did find that telomere
length was inversely correlated with age, and women had longer
telomeres than men except as young adults. All analyses controlled
for age and gender.
Harvard Medical School
scientist Cynthia C. Morton, Ph.D., who was not involved in the
study, commented, "The GERA study is especially impressive for
the large resource of DNA samples and corresponding electronic
medical records available from KP patients, and for the outstanding
group of scientists collaborating in the research.
"The intriguing
findings on telomere length in the GERA cohort are no doubt among
many yet forthcoming, prompting further investigations into the basis
for ethnic differences in telomere length such as whether specific
oral environmental exposures in ethnic groups might account for
differences in telomere lengths in saliva DNA samples," added
Dr. Morton, William Lambert Richardson Professor in Harvard's
department of obstetrics, gynecology and reproductive biology.
Like several other
investigations, GERA detected significantly longer telomeres among
African Americans than other groups, but did not reveal a significant
difference between European-Americans, Latinos and Asians.
According to the GERA
results, telomere length was positively correlated with such factors
as level of education and body mass index (BMI), and negatively
correlated with cigarette smoking and alcohol consumption. However,
telomere length was not associated with major depression or
stress-related disorders, although other studies have reported an
association between telomere length and depression and stressful
events.
Links between shorter
telomeres and risks for cardiovascular disease, diabetes, some
cancers, depression, pulmonary fibrosis, vascular dementia,
osteoarthritis and osteoporosis have been detected by Dr. Blackburn,
one of three scientists honored with the 2009 Nobel Prize in
Physiology or Medicine, and her research group as well as other labs.
Telomeres are special DNA sequences attached to the ends of each of
the 46 chromosomes in human cells. When telomeres become too short,
cells can no longer multiply.
The researchers'
presentation is titled "The Kaiser Permanente/UCSF Genetic
Epidemiology Research Study on Adult Health and Aging: Demographic
and Behavioral Influences on Telomeres and Relationship with
All-cause Mortality."
About ASHG
The American Society
of Human Genetics is the primary professional membership organization
for nearly 8,000 human genetics specialists worldwide. The ASHG
Annual Meeting is the world's largest gathering of human genetics
professionals and a forum for renowned experts in the field.
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