The association of serum 25-hydroxyvitaminD level with skeletal muscle mass and function in elderly in north urban China
Liping Meng 1, Qingqing Man1^, Linhong Yuan2, Lingxia Shen3#, Guiyuan Guo4#, Lixiang Li 1, Shanshan Jia1, Yixiong Gao1, Pengkun Song1, Fu Ping1, Jian Zhang 1,*
1Institute for Nutrition and Health, National Center for Disease Control and Prevention, China (China CDC). 2School of Public Health, Capital Medical University, Beijing, P.R.China. 3Wulituo Community Health Center, Shijingshan District, Beijing, China. 4Lugu Community Health Center, Shijingshan District, Beijing, China.
^ Co-first author.
# These Authors equally contributed to the work.
* Corresponding author, Email:
Abstract:Objectives:Toinvestigate the association of serum 25-hydroxyvitamin D levelwith skeletal muscle mass(SMM) and function in elder people in northern urban area of China. Design:Cross sectional study. Setting:The study was conducted in 2013 inShijingshan District, Beijing, China. Population:912elderly subjects aged 60 years old and above from 4 communities.Main Outcome Measure:Serum concentration of25(OH)Dwas measuredwith radioimmunoassay.Body composition including SMM was assessedby bioelectrical impendence analysis (InBody720). Grip strength and 4-meter regular gait speed were measuredfor the assessment of the skeletal muscle function. Low muscle mass was defined as relative skeletal mass index (RSMI) below 7.0kg/m2 for male and below 5.7kg/m2 for female, based on the expert consensus of Asian Working Group for Sarcopenia (AWGS).Results:Serum 25(OH)D level was positively associated with grip strength (β=0.16,SE=0.05) and upper quartile of 25(OH)D level was negatively associated with loss of grip strength (OR=0.05, 95%CI: 0.01-0.48) in malebut not in female.There were no significant association between 25(OH)D level with appendicular skeletal muscle mass (ASM), relative skeletal mass index (RSMI) and gait speed in both gender (P>0.05) .Conclusion:The present study indicated the role of vitamin D on skeletal muscle strength for male, which highlights a new possible way to improve the skeletal muscle function.
Keywords Vitamin D; Skeletal muscle mass; Skeletal muscle function; The elderly; Sarcopenia
China has been stepping into aging society with
There are approximately 202 million old people in China in 2013and this figure is expected to be doubled in 2050[1]. Aging is accompanied by significant body composition changes that are often linked to sarcopenia, which isa syndrome characterized by progressive and generalized low skeletal muscle mass and function (muscle strength and performance) with a risk of adverse outcomes such as physical disability, poor quality of life and death [2,3]. It is reported that sarcopenia has been estimated to cost $18.4 billion per year in USA[34].
Multiple mechanisms and risk factors contribute to the development of sarcopenia, such as physical inactivity, poor nutrition, gene, hormone and metabolism [5,6]. With associations between low vitamin D levels and various extraskeletal conditions found by a variety of epidemiological and prospective cohort studies over the past several years[现57],the potential effect of vitamin D on skeletal muscle mass and function (muscle and physical performance) is receiving much attention in recent years [现6-108-14]. Some recent reports indicated that muscle mass, strength, and performance reduce and the risk of falls increases in older individuals with low serum 25-hydroxyvitamin D levels[68-108].A population-basedstudyreported that after adjustment for confounders, persons withlowbaseline 25(OH)Dlevels(<25nmol/l) were 2.57 (with 95% CI 1.40-4.70, based on gripstrength) times more likely to experiencesarcopenia, compared with those withhigh(>50 nmol/l)levels[79]. However, this knowledge is limited in China.Furthermore, the conclusion on this topic was not harmonious even in the current literatures [13,14].
So a better understanding of the relationship between vitamin D level on muscle mass and function in the elderly would be meaningful for exploring a new way to improve the muscle mass and function in the elderly, and it would be particular necessary for Chinese population. Therefore, we developed the present study to investigate the association of 25(OH)D level in serum with skeletal muscle mass, grip strength and gait speed in the elderly in north urban China.
In this introduction section, it should spend more words on the situation about about vitamin D deficiency and muscle mass reduction in older Chinese people. And then lead to the hypothesis and importance of your study.
原版参考文献
[4] Siddiqui SM, Chang E, Li J, Burlage C, Zou M, Buhman KK, et al. Dietary intervention with vitamin D, calcium, and whey protein reduced fat mass and increased lean mass in rats. Nutr Res 2008;28(11):783-90.
[5] Rolland Y, Czerwinski S, Abellan Van Kan G, Morley JE, Cesari M, Onder G, et al. Sarcopenia: its
assessment, etiology, pathogenesis, consequences and future perspectives. J Nutr Health Aging
2008; 12(7): 433-50.
Subjects and methods
Participants
912elderlysubjects aged60 years old and above from 4 communities in Shijingshan district, Beijing were invited to participate in this survey duringNov. to Dem., 2013, except that: ①the individualswho suffer from serious illnesses, such as severe obesity（BMI≥30）or diabetes with serioussyndrome, serious liver, kidney or neural disease;②with the history of stroke or myocardial infarction within one year or being suffering progressive cancer.; ③sufferingjoint disease with restricted activity, hyperthyroidism or receiving estrogen therapy;④heavy smoker and alcohol addict.
Theis study protocol was approved by the Ethical Review Committee of the National Institute for Nutrition and Food Safety, Chinese Center for Disease Control and Prevention.All participants signed informed consent voluntarily.
General information
Information on demography (sex, age, previous occupation and education), lifestyle (smoke, alcohol drinking, frequency of breakfast per week, times of out-eating) and physical activity (times of moderate-to-vigorous exercise/housework per week and the duration of each time of exercise/housework) of the participants were collected with a questionnaire in a face to face interview. Moreover, the information on family socioeconomics,durationof sun explore in summer and winter separately, sleep duration per day and nutrients supplements intakes was also collected by this questionnaire.
Dietary Survey
A verified semi-quantified food frequency questionnaire (FFQ) with 45 food items was used to assess dietary energy and protein intake (cited reference) . FFQ was validitied a reliable method to assess dietary energy and protein in Chinese [15]. The subjects’ habitual diets during the past one year were asked by well trained interviewers in the face to face interview. Food photos with measured portion size were used to aid participants in estimating intake amounts for improving the quality of the data. Energy and protein intake was calculated based on food intakes from FFQ and Chinese food composition table (2002).
Anthropometry measurement
Height was measured to the nearest 0.1 cm with a freestanding stadiometer mounted on a rigid tripod (GMCS-I, Xindong Huateng Sports Equipment Co. Ltd., Beijing, China). Fasting body weight was measured to the nearest 0.1 kg using a balance-beam scale (RGT-140, Weighing Apparatus Co. Ltd. Changzhou Wujin, China) with participants wearing only underwear. Body mass index (BMI, kg/m2) was calculated as weight (kg) divided by the square of height (m).
Muscle mass and functionmeasurement
Muscle mass measurement
Body composition was assessedby Bioelectrical Impendence Analysis (BIA), with abody composition analyzer (InBody720,Biospace, Korea).InBody 720 is asegmental multiple frequencies bioelectrical impedance device measuring the voltage drop in the upper and lower body. The InBody720 uses
eight points of tactile electrodes (contact at thehands and feet) and six frequencies (1, 5,50, 250, 500 kHz and 1MkHz)to detect the segmentalbody composition, including body water, fat, muscle and mineral, and so on. The subjects were asked tobe fasting over two hours, put off the shoes and socks, ware underwear only and then standover the electrodes of the machine and wait for the results for 3‐5 minutes. Based on the output of InBody720, we calculated skeletal muscle mass (SMM), appendicular skeletal muscle mass (ASM), and relative skeletal mass index (RSMI) with ASM (kg) divided by the square of height (m).
Handgrip strength
A handgripdynamometer(EH101, CAMRY, Guangdong Xiangshan Weighting Apparatus Group LTD, Zhongshan, China).The participants were instructed to holdthe dynamometer in the dominant hand with standing posture and were strongly encouraged to give a maximum isometric effort, which is maintained for about 5 seconds. Maximum strength was measured twice and the higher recorded value was considered maximal grip strength. At least a rest of 5 minuteswas required between each measurement.
Gait speed
The 4-meter regular gait speed was measured to assess the muscle performance. The elderly were asked to walk with the regular speed intheir ordinary shoes for 4 meter. The timetaken was recorded in seconds (S). The gait speedtest was performed once.
Vitamin D measurement
4.5 ml fastingvenous blood samples were obtained and serum was stored at–70℃until analysis. The serum concentration of 25-hydroxy vitamin D(25(OH)D) was used as a measure of vitamin D status.Serum concentration of25(OH)Dwasmeasuredwith an immunoradiometric assay(DIAsource ImmunoAssays S.A., Louvain-la-Neuve, Belgium).All samples wereanalyzed at the same time. According to the manufacturer,the reference range is 6.6-24.5 ng/ml (16.5–61.3 nmol/l) for 25(OH)D, Intra- and inter-coefficient of variation (CV) for 25OHDis 4.7% and 9.1%, respectively.
Definition of Variables and Outcomes
In the present study, sarcopenia was defined by the expert consensus of Asian Working Group for Sarcopenia (AWGS) [1116].Participants who were low muscle mass at the same time either low grip strength or low gait speed were defined as sarcopenia. Low muscle mass was defined as RSMI<7.0kg/m2 for male and RSMI5.7kg/m2 for female. Low grip strength was defined as handgripstrength below 26kg for men and below 18kg for women. Low gait speed was defined as 0.8 m/s for both gender.
According to the widely used criteria[1217], the following ranges for the classification of 25(OH)D status: Deficiency: 20 ng/mL;Insufficiency: 20-29.9 ng/mL; Sufficiency:≥30ng/ml.
Statistical analysis
SAS packageversion 9.1 (SAS Institute Inc, Cary, NC) was used foranalyses.Covariance analysis with General Linear Model (GLM) was used to calculate the mean and 95%CIofgait speed, grip strength SMM, ASM and RSMI by vitamin D quartileafter adjustment for covariates such as sex, age, sun explore and physical activity. The prevalence of sarcopenia and its’ components were described as prevalence and 95% CI.Wald chi-square test was used to compare the difference of the prevalence among vitamin D quartiles.Non-condition Logistical Regression Model wasemployed to explore the association of vitamin D withmuscle mass and function.Four models were explored with low SMM, low grip, low gait speed and sarcopenia as a dependent variable, respectively.No other variable except vitamin D level was included as independent variable in Unadjusted Model. We drew 11potential confounders (gender, age, occupation, sun exposure, physical activities, education, body fat percentage, smoke, alcohol drinking, dietary protein and energy intake) as independent variables in Model I.On the basis of Model I, low grip strength, low gait speed and Low SMM, wereadditionally adjusted foreach other in Model II.
P values of less than 0.05 were considered statistically significant.
Results
General Information
A total of 912 elderly residents (316 males and 596 females) aged sixty years and above participated in the survey. A major proportion of the subjects were those with 60-79 years old (94.8%), with mean age 67.9 years old (with standard deviation 6.2 y). The percentage of education in middle school and technical secondary school and belowwas 96.4%, andprevious occupation of manual worker andmental workeraccounted for 80.6%. The percentage of smoking and alcohol drinking was 13.8% and 21.6%, respectively.
Serum 25(OH)D level of the elderly was 14.7ng/ml, which was 15.1 in male and 14.6in female, respectively. The prevalence of vitamin D deficiency was 74.7% in male and 78.5% in female. Dietary mean intake of energy was 1512.0 Kcal/d and protein intake was 61.1 g/d, respectively (Table 1).
Table 1 Basic characteristics of the study population (%)a
Descriptive Variables / Male / Female / Totaln / % / N / % / n / %
Age group
60-69 / 203 / 64.2 / 399 / 67.0 / 602 / 66.0
70-79 / 90 / 28.5 / 173 / 29.0 / 263 / 28.8
>=80 / 23 / 7.3 / 24 / 4.0 / 47 / 5.2
Education
Primary school and below / 57 / 18.0 / 180 / 30.2 / 237 / 26.0
Middle/technical secondary school / 240 / 76.0 / 402 / 67.5 / 642 / 70.4
College and above / 19 / 6.0 / 14 / 2.3 / 33 / 3.6
Previous occupation
Manual worker / 194 / 61.4 / 317 / 53.2 / 511 / 56.0
Peasant / 16 / 5.1 / 80 / 13.4 / 96 / 10.5
Mental worker / 85 / 26.9 / 139 / 23.3 / 224 / 24.6
Others / 21 / 6.6 / 60 / 10.1 / 81 / 8.9
Smoking
Yes, every day / 85 / 26.9 / 24 / 4.0 / 109 / 12.0
Yes, but not everyday / 14 / 4.4 / 2 / 0.4 / 16 / 1.8
No / 217 / 68.7 / 570 / 95.6 / 787 / 86.2
Alcohol drinking
Yes, everyday / 81 / 25.6 / 10 / 1.7 / 91 / 10.0
Yes, 1-6 times per week / 36 / 11.4 / 10 / 1.7 / 46 / 5.0
Yes, <1 times per week / 42 / 13.3 / 18 / 3.0 / 60 / 6.6
No / 157 / 49.7 / 558 / 93.6 / 715 / 78.4
Vitamin D category
Deficiency / 236 / 74.7 / 468 / 78.5 / 704 / 77.2
Insufficiency / 49 / 15.5 / 82 / 13.8 / 131 / 14.4
Sufficiency / 31 / 9.81 / 46 / 7.72 / 77 / 8.4
Physical exercise at least once a week
No / 220 / 69.6 / 442 / 74.2 / 662 / 72.6
Yes / 96 / 30.4 / 154 / 25.8 / 250 / 27.4
Mean / SE / Mean / SE / Mean / SE
Serum 25(OH)D（ng/ml） / 15.1 / 0.6 / 14.6 / 0.4 / 14.7 / 0.3
BMI (Kg/m2) / 25.2 / 0.2 / 25.2 / 0.2 / 25.2 / 0.1
Sun exposure in Winter (hr) / 2.3 / 0.1 / 2.0 / 0.1 / 2.1 / 0.0
Sunexposurein Summer (hr) / 2.0 / 0.1 / 1.6 / 0.0 / 1.8 / 0.0
Sleep duration per day / 7.2 / 0.1 / 6.7 / 0.1 / 6.9 / 0.0
Energy intake (Kcal/d) / 1719.1 / 35.8 / 1399.3 / 24.7 / 1512.0 / 21.0
Protein intake (g/d) / 72.4 / 1.6 / 55.0 / 1.1 / 61.1 / 0.9
aContinuous variables were expressed as meanand standard error and categorical variables were expressed as cases and prevalence.
Skeletal muscle mass and function distribution by vitamin D level
There was a significant difference of grip strength among vitamin D quartiles. While no significant difference was found eitherin mean gait speed, SMM, ASM and RSMI, or in the rate of low SMM, low gait speed and sarcopenia among vitamin D quartiles (P>0.05) , Table 2.
Table 2Muscle mass and function by selected serum vitamin D quartileb
Vitamin D Quartile c / F / PQI / Q2 / Q3 / Q4
Gait speed (m/s) / 1.01(0.95, 1.06) / 0.94(0.90, 0.98) / 0.94(0.89, 0.98) / 0.95(0.89, 1.00) / 2.20 / 0.09
Grip strength (kg) / 26.44(25.26, 27.62) / 27.07(26.21, 27.92) / 27.97(27.09, 28.86) / 28.07(26.93, 29.21) / 2.90 / 0.03
SMM (kg) / 24.18 (23.49, 24.87) / 23.68 (23.17, 24.18) / 23.52 (22.99, 24.06 ) / 23.47 (22.78, 24.16) / 1.20 / 0.31
ASM (kg) / 17.78 (16.76, 18.80) / 18.12 (17.52, 18.73) / 17.93 (17.35, 18.50) / 17.72 (17.00, 18.44) / 0.41 / 0.75
RSMI (kg/m2) / 6.94(6.77, 7.11) / 6.83(6.71, 6.95) / 6.80(6.67, 6.93) / 6.81(6.65, 6.98) / 0.85 / 0.47
Low SMM (%) / 12.00(11.84, 12.16) / 16.04(15.94, 16.14) / 12.29(12.18, 12.40) / 7.32(7.15, 7.49) / 5.45 / 0.14
Low grip strength (%) / 20.00(19.84, 20.16) / 23.89(23.79, 23.99) / 18.09(17.99, 18.19) / 15.45(15.29, 15.61) / 6.46 / 0.09
Low gait speed (%) / 15.20(5.43, 5.77) / 20.48(20.38, 20.58) / 23.21(23.11, 23.31) / 17.07(16.91, 17.23) / 4.35 / 0.23
Sarcopenia (%) / 5.60(15.04, 15.36) / 8.53(8.42, 8.64) / 8.53(8.42, 8.64) / 4.88(4.71, 5.05) / 5.93 / 0.12
b Continuous variables were described as mean and 95%CI. Covariant analysis adjusted by sex, age, sun explore and physical activity was used to test the difference among vitamin D quartiles. Categorical variables were described as prevalence and 95%CI.Chi-square test for the difference of the prevalence among vitamin D quartiles was used.
c Mean and standard error of 25(OH) D in Q1, Q2, Q3, Q4 was 3.5±0.1 ng/ml, 9.0±0.1 ng/ml, 17.0±0.2ng/ml, and 33.4±0.8ng/ml, respectively.
Association of vitamin D with skeletal muscle mass and function
As shown in table 3,serum 25(OH)D level was positively associated with grip strength with β= 0.16 in male but not in female. There were no significant association between 25(OH)D level with ASM, RSMI and gait speed in both gender (P>0.05).
Table 3 Multiple linear regression results
Male / Femaleβ / SE / P / β / SE / P
Gait speed (m/s) / -0.002 / 0.002 / 0.267 / -0.001 / 0.001 / 0.343
Grip strength (kg) / 0.160 / 0.046 / 0.001 / 0.013 / 0.019 / 0.493
ASM (kg) / -0.010 / 0.026 / 0.696 / -0.007 / 0.007 / 0.341
RSMI (kg/m2) / -0.005 / 0.006 / 0.414 / -0.005 / 0.003 / 0.120
The OR of sarcopenia and its components with vitamin D was shown in table 4. The rate of sarcopenia, low SMM and low gait speed were not significantly associated with serum vitamin D level in both gender whetherthe model was adjusted or not (P>0.05).While a negative association between low grip strength andserum vitamin D level was found in the in male but not in female while low quartile of 25(OH)D as a reference. Though OR decreased from 0.13 in unadjusted model to 0.05 in model II with more confounders added, the P value of significant test was quite low (p<0.0001).
Table 4 Logistic odds ratio for skeletal muscle mass and function with serum vitamin D percentiles
Male / FemaleUnadjusted / Model I / Model II / Unadjusted / Model I / Model II
Low gait speed
Q1 / 1.00 / 1.00 / 1.00 / 1.00 / 1.00 / 1.00
Q2 / 0.87(0.37, 2.07) / 0.61 (0.22, 1.65) / 0.64 (0.23, 1.74) / 1.72 (0.92, 3.21) / 1.82 (0.87, 3.79) / 1.63 (0.78, 3.44)
Q3 / 0.39 (0.15, 1.02) / 0.44 (0.15, 1.28) / 0.47 (0.16, 1.37) / 1.29 (0.69, 2.41) / 1.47 (0.70, 3.08) / 1.35 (0.64, 2.86)
Q4 / 0.37 (0.12, 1.16) / 0.24 (0.06, 0.99) / 0.31 (0.07, 1.29) / 1.36 (0.64, 2.88) / 1.61 (0.67, 3.90) / 1.52 (0.63, 3.71)
Low grip strength
Q1 / 1.00 / 1.00 / 1.00 / 1.00 / 1.00 / 1.00
Q2 / 0.78 (0.31, 1.94) / 0.73 (0.26, 2.08) / 0.58 (0.20, 1.65) / 2.37 (1.00, 5.59) / 2.22 (0.88, 5.64) / 1.98 (0.77, 5.08)
Q3 / 0.36 (0.13, 1.01) / 0.56 (0.18, 1.73) / 0.43 (0.14, 1.33) / 1.94 (0.82, 4.58) / 1.74 (0.68, 4.44) / 1.57 (0.61, 4.05)
Q4 / 0.13 (0.03, 0.67) / 0.07 (0.01, 0.66) / 0.05 (0.01, 0.48) / 1.71 (0.62,4 .72) / 1.73 (0.57, 5.31) / 1.65 (0.53, 5.08)
Low SMM
Q1 / 1.00 / 1.00 / 1.00 / 1.00 / 1.00 / 1.00
Q2 / 1.10 (0.45, 2.69) / 1.37 (0.53, 3.52) / 1.47 (0.56, 3.87) / 1.62 (0.78, 3.37) / 1.84 (0.86, 3.95) / 1.84 (0.86, 3.95)
Q3 / 1.05 (0.42, 2.66) / 1.12 (0.43, 2.95) / 1.25 (0.46, 3.36) / 2.15 (0.96, 4.38) / 2.43 (0.97, 5.12) / 2.43 (0.97, 5.12)
Q4 / 1.08 (0.38, 3.03) / 1.59 (0.52, 4.80) / 1.98 (0.63, 6.18) / 1.08 (0.43, 2.70) / 1.34 (0.52, 3.46) / 1.34 (0.52, 3.46)
Sarcopenia
Q1 / 1.00 / 1.00 / 1.00 / 1.00 / 1.00 / 1.00
Q2 / 0.46 (0.13, 1.67) / 0.63 (0.15, 2.69) / 0.90 (0.17, 4.72) / 0.57 (0.25, 1.31) / 0.49 (0.15, 1.66) / 0.89 (0.22, 3.44)
Q3 / 0.46 (0.13, 1.69) / 1.22 (0.26, 5.80) / 1.05 (0.16, 6.77) / 0.43 (0.19, 0.95) / 0.32 (0.10, 1.02) / 0.43 (0.12, 1.57)
Q4 / 0.36 (0.10, 1.40) / 0.64 (0.11, 3.77) / 0.25 (0.03, 2.12) / 0.76 (0.28, 2.08) / 1.05 (0.22, 5.14) / 1.23 (0.22, 6.78)
a Model I was adjusted for gender, age, occupation, sun exposure, physical activities, education, body fat percentage, smoke, alcohol drinking, dietary protein and energy intake. In Model II, low grip strength, low gait speed and Low SMM, wereadditionally adjusted foreach other.
Discussion
1.This is the first study on the association between vitamin D status and skeletal muscle mass and function in the elderly in China, Prevalence of Vitamin D Deficiency
The present study showed that the mean concentration of 25(OH)D is 14.6-15.1 ng/ml and the prevalence of vitamin D deficiency in the elderly in north urban is 71.8%, which is close to similar studies in China. Two studies, conducted in Beijing and Shanghai respectively, reported that the mean level of 25(OH)D ranged from 14.4 to 18.1ng/ml and the rate of Vitamin D deficiency was 65%-72% in the elderly ((25OH) <20 ng/mL) [13, 14]. The prevalence of vitamin D deficiency in this study was similar to that in Northern Iran (70.1%) [15]. However, it was lower than that in Argentina (88% in women≥65 years old)[16] and most Europe countries[17]. Actually, there was a very large range of variation worldwide in vitamin D status in the elderly due to different latitude, religious, nutritional policy, culture, lifestyle, and so on[17-19].
Low serum 25(OH) D concentration was reported associated with greater all-cause mortality in older community-dwelling women [20]. Fortunately, studies showed that vitamin D level can be improved by effective measures, such as vitamin D supplement or sufficient sun exposure [21, 22]. The poor status of vitamin D in Chinese population, especially in ageing people is getting much more attention and several approaches have been taken to address this problem. A higher Recommend Nutrients Intake (RNI) of vitamin D for the elderly was revised in 2013, which would raise more concerns for vitamin D intake. More public health policy and action should be further developed to reduce the high prevalence of vitamin D deficiency in Chinese people.
Vitamin D insufficiency is prevalent in all ages, especially in older adults. Older adults are more easily suffering vitamin D deficiency because of various risk factors: decreased dietary intake, diminished sunlight exposure, impaired intestinal absorption, and impaired hydroxylation in the liver and kidneys [yuan4].
2. The prevalence of sarcopenia
Research on sarcopenia was limited. According to our knowledge, this is the first study on the prevalence of sarcopenia in the elderly in China. The prevalence of sarcopenia in Chinese urban elderly was 4.88-8.53%, ranged by vitamin D percentile, which was similar to that in Taiwan [23] but lower than that in Barcelona (33%) [24]. There was a large variety of the prevalence of sarcopenia and low muscle mass worldwide [23-25]. On average, it is estimated that 5–13% of elderly people aged 60–70 years are affected by sarcopenia and the numbers increase to 11–50% for those aged 80 or above [25]. The diversity of the prevalence of sarcopenia could be partly interpreted by its’ etiology [26,27]. Furthermore, the difference of diagnosed criteria, status of the sampling subjects and the methods of measurement might contribute to the diversity of the prevalence.
Though sarcopenia bring more health risk, it can be preventable. An increasing number of evidence from clinical trials showed that skeletal muscle strength and function, even muscle mass was improved by physical exercise and/or dietary intervention [21, 28,29]. More emphasis should be put to increase the awareness, screening, prevention and control of sarcopenia and to improve the health and quality of the elderly.