Longer Life Ahead for Senior Citizens Who Build
Clinicians need to focus on ways to improve body
composition, rather than on BMI alone, when counseling older adults on
March 14, 2014 – There seems to be no end to the
conflict among those who research senior citizens between deciding if
seniors should be thin or a little on the heavy side to achieve a longer
life. The latest opinion from UCLA researchers says the more muscle mass
older Americans have, the likely they are to die prematurely. They add
to the growing evidence that overall body composition is a better
predictor of longevity that using the body mass index (BMI) measurement.
The study, published in the American Journal of
Medicine, is the culmination of previous UCLA research led by Dr.
Preethi Srikanthan, an assistant clinical professor in the endocrinology
division at the David Geffen School of Medicine at UCLA, that found that
building muscle mass is important in decreasing metabolic risk.
"As there is no gold-standard measure of body
composition, several studies have addressed this question using
different measurement techniques and have obtained different results,"
"So many studies on the mortality impact of obesity
focus on BMI. Our study indicates that clinicians need to be focusing on
ways to improve body composition, rather than on BMI alone, when
counseling older adults on preventative health behaviors."
The researchers analyzed data collected by the
National Health and Nutrition Examination Survey (NHANES) III, conducted
between 1988 and 1994. They focused on a group of 3,659 individuals that
included men who were 55 or older and women who were 65 or older at the
time of the survey. The authors then determined how many of those
individuals had died from natural causes based on a follow-up survey
done in 2004.
The body composition of the study subjects was
measured using bioelectrical impedance, which involves running an
electrical current through the body. Muscle allows the current to pass
more easily than fat does, due to muscle's water content. In this way,
the researchers could determine a muscle mass index - the amount of
muscle relative to height - similar to a body mass index.
They looked at how this muscle mass index was
related to the risk of death. They found that all-cause mortality was
significantly lower in the fourth quartile of muscle mass index compared
with the first quartile.
"In other words, the greater your muscle mass, the
lower your risk of death," said Dr. Arun Karlamangla, an associate
professor in the geriatrics division at the Geffen School and the
"Thus, rather than worrying about weight or body
mass index, we should be trying to maximize and maintain muscle mass."
This study does have some limitations. For
instance, one cannot definitively establish a cause-and-effect
relationship between muscle mass and survival using a cohort study such
as NHANES III.
"But we can say that muscle mass seems to be an
important predictor of risk of death," Srikanthan said. In addition,
bioelectrical impedance is not the most advanced measurement technique,
though the NHANES III measurements were conducted in a very rigorous
fashion "and practically, this is the best situation possible in a study
of this size," she noted.
"Despite these limitations, this study establishes
the independent survival prediction ability of muscle mass as measured
by bioelectrical impedance in older adults, using data from a large,
nationally representative cohort," Srikanthan and Karlamangla write,
adding that BMI's association with mortality in older adults has proven
"We conclude that measurement of muscle mass
relative to body height should be added to the toolbox of clinicians
caring for older adults. Future research should determine the type and
duration of exercise interventions that improve muscle mass and
potentially increase survival in (healthy), older adults."
The research was funded by
National Institutes of Health.
The UCLA Division of
Endocrinology, Diabetes and Hypertension, part of the department of
medicine at the David Geffen School of Medicine at UCLA, provides
consultative, diagnostic and therapeutic services for the full range of
The UCLA Division of Geriatrics,
within the department of medicine at the David Geffen School of Medicine
at UCLA, offers comprehensive outpatient and inpatient services at
several convenient locations and works closely with other UCLA programs
that strive to improve or maintain the quality of life of seniors. UCLA
geriatricians are specialists in managing the overall health of people
age 65 and older and treating medical disorders that frequently affect
the elderly, including falls and immobility, urinary incontinence,
memory loss and dementia, arthritis, high blood pressure, heart disease,
osteoporosis, and diabetes. As a result of their specialized training,
geriatricians can knowledgably consider and address a broad spectrum of
health-related factors - including medical, psychological and social -
when treating their patients.