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Epidemiology of Factors Associated with Low Muscle Mass in Elderly

In a collaborative research, funded by the Singapore Economic Development Board, Changi General Hospital, and Abbott, the first part of the SHIELD study aimed to identify factors that are associated with muscle mass loss in community-dwelling elderly Singaporeans, through a cross-sectional study.

by Deborah Seah

The Singaporean population has been seeing a steady growth its elderly population, with an increase from 13.7 percent of those aged 65 and above in 2018 to 14.4 percent in 2019. Median age of the resident population has also risen from 40.8 years in 2018 to 41.1 in 2019.1

Growth in the ageing population will contribute to a paradigm shift in healthcare demands, as age-related disease will naturally be on the rise. Proving the need for an evidence-based strategy in addressing these healthcare needs of an ageing population, which will translate into better establishment of public health interventions.

Age-Related Muscle Loss

Proposed in 1989 by Irwin H. Rosenberg, the term ‘sarcopenia’, is used to describe age-related degeneration of muscle mass. The word stems from the Greek root words, ‘sarx’ for flesh and ‘penia’ for loss. It has been recognised to expound the loss of skeletal muscle mass and reduced muscle strength in relation to increasing age.2 A systematic review and meta-analysis estimated a prevalence of 10 percent in both men and women worldwide. This analysis was conducted on a total of 58,404 individuals.3

Cross-sectional study conducted in from May 2015 to February 2016 on 115 Singaporean patients of 65 years and older found that within the sample, 44.3 percent of patients had sarcopenia.4 Sarcopenia is often also associated with frailty and fall risk due to the loss of muscle strength. The same study also found a higher comorbidity, increased dependency and the need for special medical care.

These studies underlie the impetus for further research on factors associated with sarcopenia and the development of specific public health interventions to improve or maintain muscle health, encourage healthy ageing and thereby reducing burden on healthcare resources.


The SHIELD Study

Strengthening Health In ELDerly through nutrition (SHIELD) study first started in 2017 aimed to gather information and gain understanding of factors associated with low muscle mass among community-dwelling elderly Singaporeans aged 65 and older. Such information can be essential for formulating public health policies and measures to help the elderly prevent or even slow down the rate of muscle degradation with normal nutritional status.

The study was jointly conducted by Changi General Hospital, Abbott, and SingHealth Polyclinics, to provide collaborative efforts to investigate the effects of nutritional intervention. In the first part of the research a cross-sectional study was conducted on 400 patients recruited from the general public, community centres, polyclinics and hospitals. It was hypothesized that community-dwelling elderly with normal nutritional status would have a lower risk of muscle loss compared to those who are at risk of malnutrition.5

“Community-dwelling older people with normal nutritional status were chosen as they may represent the ideal target for effective interventions before the onset of significant malnutrition and loss of muscle mass, leading to adverse health outcomes.” Said Dr Low Yen Ling.

Objectives of the study were to describe anthropometry, body composition, appendicular skeletal muscle mass index (ASMI) and the prevalence of low ASMI among elderly with normal nutritional status. Other information such as the socio-demographic data, blood samples and other comorbidities were collected to determine any other associated factors to ASMI.


Data Collection and Results

Participants for the study were selected base on defined inclusion and exclusion criteria. For eligibility, males or females had to be 65 years old or above and shown to have independent mobility with or without aid. Nutritional status was another criteria for inclusion to the study, this was essential as it would fulfil the study objective in determining the prevalence of low ASMI in elderly with normal nutrition.

“Participant’s malnutrition status was determined using the Malnutrition Universal Screening Tool (MUST). It consists of three components, namely Body Mass Index (BMI), weight loss and acute disease that can affect the risk of malnutrition due to no nutritional intake.” Dr Low Yen Ling explains the inclusion criteria of participants to the study.

She adds that, “In order to qualify as normal nutritional status, participants’ overall MUST score has to be ‘zero’, indicating that they are not at risk of malnutrition.”

Those who were excluded were elderly with diseases or disorders such as dementia, Type 1 or Type 2 Diabetes, any active infectious disease, severe gastrointestinal disorders, cystic fibrosis, end stage organ or pre-terminal diseases, acute myocardial infarction within the last 30 days from the screening, or active malignancy in the last five years.5

To determine the lean muscle mass of the participants, Appendicular Skeletal Muscle Index (ASMI) was measured using bioimpedance analysis (BIA). This method was selected due to its low cost, safe, convenient, and non-invasive approach to measuring body composition. Measurements were defined based on the Asian Working Group for Sarcopenia (AWGS) recommendation that states the advised cut-off values using BIA are 7.0 kg per m2 for men and 5.7 kg per m2 for women.6 BIA makes use of the obstructive properties in biological tissue against electric current to estimate fat mass, muscle mass, and bone mass.7

Anthropometric tape was also used to measure mid-upper arm circumference and calf circumference. Other socio-demographic data were also collected during the initial baseline visit. Co-morbidities, and blood samples were also collected.

Overall, within the study population, the prevalence of low ASMI was 20.6 percent with higher prevalence seen in females (24.9%) compared to males (15.5%). From the analysis of data, it was found that gender, age, Body Mass Index (BMI), and calf circumference showed an association with low ASMI. Age is a known major risk factor for low ASMI, the researchers adjusted this association for gender, BMI, and calf circumference. Using logistic regression models, for every one-year increase in age there would be a 13 percent increase in odds of having low ASMI. For every ten-year increase there is a 3.4-fold increase in the odds of having low ASMI.


Recommendations for Public Health Strategy

Through the SHIELD study, the researchers aimed to tackle information gaps in nutritional needs for ageing Asian populations as well as identifying the effect of good nutrition management on health among the elderly in Singapore. With the study results the team hoped to be able to demonstrate to healthcare professionals the need for recommending good lifestyle practices in physical activity and diet to support muscle health in the elderly.

“Healthcare professionals should be aware of the importance of muscle health in older people and encourage their patients to consider early screening of their muscle mass and adopt a lifestyle that incorporates physical activity along with a high-protein, well-balanced diet.” Said Adjunct Associate Professor Tan Ngiap Chuan.

He also shares that it is important for “first line” healthcare professionals such as primary care providers to include muscle health screening for the elderly during clinic consultations and direct patients who are at risk of low muscle mass for physiotherapy sessions at local polyclinics or hospitals.

The findings will also help to provide an evidence-based approach to emphasise the requirements in development of public health strategies in ensuring maintenance and improvement of muscle health in the Singaporean population.

Adjunct Associate Professor Tan Ngiap Chuan added on saying that in the future, “muscle health checks including calf circumference measurement and muscle grip strength test will be incorporated in regular health checks in the clinics to standardise the way we chart the progress of muscle health for the elderly and shield them from any muscle less.”


SHIELD Study Stage 2

Following the first part of the SHIELD study, a second part will be conducted over a period of 18 months this will evaluate the effect of nutritional intervention in elderly who are at risk of undernutrition. The second part of the SHIELD study will be using a randomised double-blind controlled clinical trial.

“This group of elderly participants will be split into two groups – one taking oral nutrition supplements and the other taking a placebo supplement. The study will investigate how nutritional interventions affect health outcomes and healthcare costs of community living older people at risk of undernutrition.” Shared Adjunct Assistant Professor Samuel Chew.

Providing an overview of the second part of the SHIELD study, Adjunct Assistant Professor Samuel Chew explained that the results from the clinical trial aims to devise interventions and guide practise for better nutrition and muscle health in older people in Singapore. Through these interventions they hope to potentially achieve improved clinical outcome, prevent early disability, improved recovery from illness and promote healthy ageing. [APBN]


  1. Department of Statistics, Singapore, (September 2019). Retrieved from: https://www.singstat.gov.sg/-/media/files/publications/population/population2019.pdf
  2. Cruz-Jentoft, A. J., Baeyens, J. P., Bauer, J. M., Boirie, Y., Cederholm, T., Landi, F., … European Working Group on Sarcopenia in Older People (2010). Sarcopenia: European consensus on definition and diagnosis: Report of the European Working Group on Sarcopenia in Older People. Age and ageing, 39(4), 412–423. doi:10.1093/ageing/afq034
  3. Shafiee, G., Keshtkar, A., Soltani, A., Ahadi, Z., Larijani, B., & Heshmat, R. (2017). Prevalence of sarcopenia in the world: a systematic review and meta- analysis of general population studies. Journal of diabetes and metabolic disorders, 16, 21. doi:10.1186/s40200-017-0302-x
  4. Li Feng Tan, Zhen Yu Lim, Rachel Choe, Santhosh Seetharaman, Reshma Merchant (2017). Screening for Frailty and Sarcopenia among older person in Medical Outpatient clinics and its Associations with healthcare burden. Journal of the American Medical Directors Association, Vol 18, Issue 7, p583-587. doi: 10.1016/j.jamda.2017.01.004
  5. Tey, S. L., Chew, S., How, C. H., Yalawar, M., Baggs, G., Chow, W. L., … Huynh, D. (2019). Factors associated with muscle mass in community-dwelling older people in Singapore: Findings from the SHIELD study. PloS one, 14(10), e0223222. doi:10.1371/journal.pone.0223222
  6. Liang-Kung Chen, Li-Kuo Liu, Jean Woo, Prasert Assantachai, Tung-Wai Auyeung, Kamaruzzaman Shahrul Bahyah, Ming-Yueh Chou, Liang-Yu Chen, Pi-Shan Hsu, Orapitchaya Krairit, Jenny S.W. Lee, Wei-Ju Lee, Yunhwan Lee, Chih-Kuang Liang, Panita Limpawattana, Chu-Sheng Lin, Li-Ning Peng, Shosuke Satake, Takao Suzuki, Chang Won Won, Chih-Hsing Wu, Si-Nan Wu, Teimei Zhang, Ping Zeng, Masahiro Akishita, Hidenori Arai (2014). Sarcopenia in Asia: Consensus Report of the Asian Working Group for Sarcopenia. Journal of the American Medical Directors Association, Vol 15, Issue 2, p95-101. doi: 10.1016/j.jamda.2013.11.025
  7. Khalil, S. F., Mohktar, M. S., & Ibrahim, F. (2014). The theory and fundamentals of bioimpedance analysis in clinical status monitoring and diagnosis of diseases. Sensors (Basel, Switzerland), 14(6), 10895–10928. doi:10.3390/s140610895

About the Interviewees

Dr Low Yen Ling, Director, Research & Development, Abbott Nutrition Asia Pacific Centre


Adjunct Associate Professor Tan Ngiap Chuan, Director, Research, SingHealth Polyclinics and Vice-chair, Research, SingHealth-Duke NUS Family Medicine Academic Clinical Programme


Adjunct Assistant Professor Samuel Chew, Senior Consultant Geriatric Medicine, Changi General Hospital