Abstract
Background. Sarcopenia refers to the loss of skeletal muscle
mass with age. The objective of this study was to determine the prevalence of
sarcopenia in a population of older, community-dwelling research volunteers.
Methods. Appendicular skeletal muscle mass was measured by
dual x-ray absorptiometry in 195 women aged 64 to 93 years and 142 men aged 64
to 92 years. We defined sarcopenia as appendicular skeletal muscle mass/height2
(square meters) less than 2 standard deviations* below the mean for young,
healthy reference populations. We used two different reference populations and
compared prevalence in our population to that reported in previous studies.
Body mass index (BMI) was calculated and physical activity and performance were
measured with the Physical Activity Scale for the Elderly, the Short Physical
Performance Battery, and the Physical Performance Test. We measured
health-related quality of life by using the SF-36 general health survey. Serum
estrone, estradiol, sex hormone-binding globulin, parathyroid hormone, and
25-hydroxy vitamin D were measured in all participants and bioavailable
testosterone was measured only in men. Leg press strength and leg press power
were determined in men.
Results. The prevalence of sarcopenia
[sacro—flesh
or muscle + penia loss of] in our cohort was 22.6% in women and 26.8% in men. A
subgroup analysis of women and men 80 years or older revealed prevalence rates of
31.0% and 52.9%, respectively. In women, skeletal muscle mass
correlated significantly with BMI and levels of serum estrone, estradiol, and
25-hydroxy vitamin D; in men, it correlated significantly with BMI, single leg
stance time, leg press strength, leg press power, SF-36 general health score,
Physical Performance Test total score, and bioavailable testosterone levels.
With the use of linear regression analysis, BMI was the only predictor of
appendicular skeletal muscle mass in women, accounting for 47.9% of the
variance (p < .05). In men, BMI accounted for 50.1%, mean strength
accounted for 10.3%, mean power accounted for 4.1%, and bioavailable
testosterone accounted for 2.6% of the variance in appendicular skeletal muscle
mass (p < .05).
Conclusions.Sarcopenia is common in adults over the age of
65 years and increases with age. BMI is a strong predictor of skeletal muscle
mass in women and men. Strength, power, and
bioavailable testosterone are further contributors in men. These data
suggest that interventions to target nutrition, strength training, and testosterone
replacement therapy should be further investigated for their role in
preventing muscle loss with age.
* Two standard deviations means that 95%
of the reference groups (young men when comparing to their test group of
elderly men, and like with women). Thus
a man whose strength was found to be equal to or less than the weakest 2.5% of
the reference group of healthy young men was considered to suffer from
sarcopenia (and the same for comparing elderly women to healthy young
women).
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Journal of Gerontology: · Oxford Journals, · Life Sciences & Medicine,
·
The Journals of Gerontology: Series
A, · Volume 58, Issue 5, · Pp. M436-M440, Gerontol
A Biol Sci Med Sci (2003) 58 (5):
M436-M440. doi: 10.1093/gerona/58.5.M436 http://biomedgerontology.oxfordjournals.org/content/58/5/M436.short
Prevalence
of Sarcopenia and Predictors of Skeletal Muscle Mass in Non-obese Women Who Are
Long-Term Users of Estrogen-Replacement Therapy
Abstract
Background. Sarcopenia refers to the loss of skeletal
muscle mass with age. We have found a prevalence of sarcopenia of 22.6% in
older postmenopausal women not receiving estrogen. The objective of this study
was to determine the prevalence of sarcopenia in a population of older,
nonobese, community-dwelling women who had been long-term users of estrogen
replacement therapy (ERT).
Methods. We measured appendicular skeletal muscle mass by
dual x-ray absorptiometry (DXA) in 189 women aged 59 to 78 years old who had
been using ERT for at least 2 years (mean ± SD duration, 12.7 ± 8.2
years). We defined sarcopenia as an adjusted appendicular skeletal muscle mass
(ASM) (mass divided by height squared) more than 2 SDs below the mean
for a young healthy reference population. Health and menopause history were
obtained. Body mass index (BMI) was calculated, and physical activity and
performance were measured using the Physical Activity Scale in the Elderly, the
chair rise time, the 6-minute walk, and measures of lower extremity strength
and power. Serum estrone, estradiol, testosterone, and sex hormone binding
globulin were measured.
Results. The prevalence of sarcopenia in nonobese,
community-dwelling women who were long-term ERT users was 23.8%. Skeletal
muscle mass correlated significantly with BMI, age at the time of starting ERT,
hand grip strength, lower extremity strength and power, and testosterone level,
but not with estradiol level. In linear regression analysis, BMI, leg press
strength, and testosterone level contributed to adjusted ASM, accounting for
48.7% of the variance (p <.001).
Conclusions. Sarcopenia is as common in non-obese women who
are long-term ERT users as in community-dwelling women not using ERT, suggesting that ERT does not
protect against the muscle loss
of aging. BMI, strength, and testosterone level contributed to
appendicular skeletal mass in women. These data suggest that interventions to target nutrition, strength
training, and testosterone
replacement should be further investigated for their role in
preventing muscle loss with age.
