Project objectives 

Aims and objectives

The aim of this project is to identify a simple screening test to assess the risk for sarcopenia in primary care using a cohort of 1722 men aged 72-91 years drawn from general practices across 24 British towns and to assess the association between diet quality, physical activity and sarcopenia. The proposal’s aims are:

1. To estimate the prevalence of sarcopenia in older community dwelling men using the  EWGSOP (the European Working Group on Sarcopenia in Older People) definition
2. To evaluate the use of objective and subjective measures of gait speed in predicting  risk of having sarcopenia (EWGSOP definition) and whether they are effective in predicting adverse outcomes including incident functional outcome and mortality
3. To develop an easy-to-use screening tool for detecting sarcopenia or those at high risk of sarcopenia.
4. To examine the association between diet quality and objective measure of physical activity with sarcopenia using the EWGSOP definition

Changes to original proposal

The original project’s proposal has been carried out.

Methods 

This project was carried out in an established population based cohort study, the British Regional Heart Study (BRHS), comprising men aged 72-91 years drawn from general practices and followed up for morbidity, functional outcomes and mortality. The BRHS was established in 1978-80 in a socially and geographically representative prospective cohort of 7735 middle-aged men drawn from general practices in 24 British towns [17].  These men have been followed up and re-examined in 1998-2000 when aged 60-79 years and in 2010-2012 when aged 72-91 years.

Population: In 2010-2012, all surviving study men were invited to attend a 32 year follow-up examination at 72-91 years of age. In all, 1722 men (55% response) were examined.  Detailed measurements of anthropometry (including mid arm muscle circumference a proxy for muscle mass), blood pressure and an electrocardiogram were made and blood samples were collected. A detailed questionnaire was also completed including medical history, health behaviours, functional limitations, social circumstances, physical and social activities and diet.  Measures of grip strength and  3 metre gait speed were performed. This proposal is based on the use of this data on the cohort when aged 72-91 years and follow-up thereafter.

Exposure measures: The main exposure variable is objectively measured gait speed, subjective measures of walking speed, diet quality based on food frequency questionnaire and objective measure of physical activity (accelerometer). Diet quality based on a priori scores including the Mediterranean Diet score and Elderly Diet Score was calculated from the dietary data at 72-91 years.  Objective measurements of light, moderate and vigorous levels of activity was calculated based on the accelerometer data.

Outcome measures: Sarcopenia based on EWGSOP criteria of gait speed <0.8m or low hand grip strength and low muscle mass measured using mid arm muscle circumference (proxy for muscle mass).

Adverse outcomes - Functional limitation and mortality which are established adverse outcomes of sarcopenia.

Findings

1. It is estimated that about 14% of older men aged 70-90 have sarcopenia of which 2% are classified as having severe sarcopenia.  Sarcopenia and severe sarcopenia were defined using the European Working Group on Sarcopenia in Older People (EWGSOP). Both conditions required (i) low muscle mass and either (ii) low grip strength (<30 kg) or (iii) low gait speed (≤0.8 m/s). Severe sarcopenia required the presence of all three conditions. Participants in the lowest two-fifths of the mid arm muscle circumference (a proxy measure for muscle mass) were classified as having low muscle mass.
2. Objective measurement of gait speed was defined as time to walk 3 meter. Those in the lowest quintile of measured gait speed were over 6 times more likely to have severe sarcopenia than those in the highest quintile.  Reported subjective slow gait speed was associated with a two fold increase in risk of having severe sarcopenia.  However, gait speed alone was not sensitive in detecting people with mild or moderate  sarcopenia. Both measured and subjective measures of gait speed were associated with about a three-fold increase in risk of functional disability and a two fold increase in risk of all-cause mortality.   Thus gait speed which can be carried out in primary care may provide a first step in identifying those at high risk of severe sarcopenia and disability and who are at high risk of mortality. The findings on objective and subjective measures of gait speed and incident disability and mortality have been published in JAMDA (Papachristou et al 2016 ).
3. We have explored whether additional simple questions such as weight loss and simple measures such as BMI may improve specificity in the detection of people with sarcopenia. Additonal information on weight loss or obesity did not improve detection of moderate or severe sarcopenia beyond gait speed. However measurement of obesity improved prediction of disability beyond gait speed alone.  Thus measurement of gait speed and BMI may provide simple measures in primary care to identify those at high risk of severe sarcopenia and developing disability.
4. The associations between different intensities of objectively measured physical activity with sarcopenia using EWGSOP definition was examined in older British men. Each extra 30 minutes/day of moderate-to-vigorous PA (MVPA) was associated with a reduced risk of severe sarcopenia (adjusted relative risk [RR] 0.57, 95% confidence interval [CI] 0.32, 1.00). Each additional 1000 steps/day was associated with RR 0.79 [95% CI 0.68, 0.93]) for severe sarcopenia. No associations were seen between these physical activity measures and mild or moderate sarcopenia.  The findings indicate that regular MVPA may help reduce risk of severe sarcopenia. These findings have been presented as part of a poster entitled "Association of objectively measured physical activity and sedentary time with sarcopenia, severe sarcopenia and sarcopenic obesity in older men" at the Society of Social medicine 2016 Annual Scientific meeting in September.  In contrast to physical activity we found no association between diet quality as measured by the elderly diet index (EDI) and risk of having sarcopenia. The EDI was developed by Kourlaba et al (2009) specifically to address adherence to nutritional recommendations for older adults on the basis of the frequency of consumption of specific foods/food groups in the Modified MyPyramid for Older Adults. The EDI consists of 9 components (meat, fish and seafood, legumes, fruit, vegetables, cereals, bread, olive oil, and dairy).

Plain English summary

Sarcopenia, the loss of skeletal muscle with age, is now recognised as a major clinical problem in older people and leads to frailty, falls, disability, hospital admissions and increased mortality. The European Working Group on Sarcopenia in Older people (EWGSOP) has defined sarcopenia on the basis of low physical performance (walking speed, hand grip strength) and low muscle mass, which are not easily measureable  in routine clinical practice in primary care.  Risk assessment for sarcopenia in old age within primary care has received little attention and a simple easily applied measure to identify sarcopenia specifically in primary care settings has yet to be developed. We used data from a cohort of 1722 older men aged 72-91 years from general practices in 24 British towns to develop an easy-to-use tool to identify those with or at high risk of sarcopenia. We evaluated the use of objective and subjective measures of walking speed in predicting sarcopenia and whether they are effective in predicting adverse outcomes including disability and death and assessed whether a combination of walking speed together with simple questions and measures such as weight loss and BMI would improve the accuracy of detecting sarcopenia and predicting adverse outcomes. Finally, we examined the association between overall diet quality and physical activity and sarcopenia to assess the scope for prevention through dietary change and physical activity.

We have shown that low measured gait speed was a strong predictor of severe sarcopenia but was not sensitive in detecting people with mild or moderate sarcopenia.   Measured gait speed strongly predicted future disability and mortality in those who were free of mobility limitation.  A combination of measured gait speed and BMI improved prediction of disability but not mortality beyond gait speed alone. Whereas gait speed and weight loss improved prediction of mortality (but not disability) beyond gait speed alone.  We have shown that regular physical activity may help reduce risk of severe sarcopenia.  However there was no evidence that diet quality reduced risk of sarcopenia in this group of older men. In conclusion our findings suggest that 1) measurement of gait speed and BMI may provide useful simple measures in primary care to detect sarcopenia and identify those at high risk of disability and that 2) physical activity may reduce the risk of having severe sarcopenia. The early identification of patients with low or declining physical performance offers potential to prevent disability and frailty.

Dissemination

The project key findings will be published in our annual newsletter  in  2017 which is sent to the General Practitioners  who are key stakeholders in our research and follow-up.

Impact

These findings need to be replicated in other cohorts of elderly subjects and may provide a useful simple tool to identify those with severe sarcopenia at high risk of disability

This project was funded by the National Institute for Health Research School for Primary Care Research (project number 278)

Department of Health Disclaimer

The views and opinions expressed therein are those of the authors and do not necessarily reflect those of the NIHR School for Primary Care Research, NIHR, NHS or the Department of Health.