Musculoskeletal functional ability in three diverse Sub-Saharan Africa Populations; assessing muscle strength & function to understand healthy ageing

Around the world people are living longer than ever before. There are now 1 billion people aged over 60 years. In Africa, rising life expectancy is most rapid. The United Nations declaration of the Decade of Health Ageing 2021-2030 states there has never been a timelier opportunity to act to ensure the health of ageing adults, their families and communities. But ageing brings risk of disease, with muscles, bones and joints commonly affected (musculoskeletal disease), which limits walking and daily life. Often diseases exist together, such as with HIV and/or diabetes, this is known as multimorbidity. Multimorbidity is a high priority for global health research. Importantly, one third of all multimorbidity cases across the world include musculoskeletal disease. Currently musculoskeletal diseases account for disability than cancer and heart disease combined.

Loss of muscle strength and function is a common manifestation of ageing (known as sarcopenia), which leads to falls and fragility fractures (broken bones from low impact injuries), disability, frailty, and sometimes death. Despite this, little is known about how muscle ages in people living in sub-Saharan Africa (SSA), nor the risk factors for muscle loss or the impact on quality of life. We will study three different populations in The Gambia, Zimbabwe and South Africa. Aiming to:
i. How commonly muscle strength is impaired, physical functional is limited and sarcopenia is experienced.
ii. Understand to what extent losses in muscle strength and ability reduce the ability to perform activities of daily life, increase the risk of frailty and disability and how these impact quality of life.
iii. Identify clinical, nutritional and metabolic risk factors for losses muscle function, to inform approaches to reduce future disability, and promote healthy ageing in SSA.

Work package 1: What is the epidemiology of muscle strength, mass and function in each country? We collaborate with a team currently planning extensive community surveys in The Gambia, Zimbabwe and South Africa, which will measure spine fractures in 5040 men and women aged 40 years and over. We have a unique and time-limited opportunity to add to these surveys, data collection and detailed measurements of muscle strength, mass and function, to answer our specific study questions. We will collect data from questionnaires (e.g. joint and back pain, ability to work around the house, quality of life), body composition scans (to quantify fat and muscle mass), X-rays (to quantify osteoarthritis), muscle strength, walking and balance tests (to measure frailty), and blood tests. We will quantify levels of all musculoskeletal multimorbidities including sarcopenia, and determine how these affect disability and quality of life.
Work package 2: What are the clinical, nutritional and metabolic risk factors for low muscle strength, mass and function? Identifying risk factors for muscle impairment will aid understanding of the mechanisms underlying muscle dysfunction and highlight biomarkers that can predict disease and disability, with potential use in clinical settings. We will examine clinical (e.g. HIV, diabetes, physical inactivity, osteoarthritis) and nutritional risk factors (e.g. malnutrition, food insecurity, obesity), and measure 184 markers of metabolism and inflammation using the latest proteomic analysis of blood samples, to see which predict age-related losses in muscle.

We will feedback our findings to local communities, national health leads and policy makers, and international researchers.

This project grant offers a unique and highly-cost effective opportunity, taking advantage of a funded research platform. This MRC investment would permit detailed and novel study of muscle in some of the most rapidly ageing populations in the world. This presents a time-limited opportunity to answer these important research questions focusing on muscle health and functional ability.

In sub-Saharan Africa (SSA) shifting demographics, rapid urbanization and associated lifestyle changes are generating an exponential rise in non-communicable diseases of ageing, of which musculoskeletal diseases are a significant proportion. There is an urgent need to reduce the time people spend living with locomotor disabilities and dependence, and to maximize functional ability amongst the growing ageing populations in resource poor countries in SSA. This proposal focuses on three countries, The Gambia, South Africa and Zimbabwe. Hypothesis: In the diverse ageing populations, high levels of adiposity and chronic infection with low levels of dietary diversity and physical activity are, in differing combinations, responsible for growing levels of sarcopenia and poor functional ability.
WP1: What is the epidemiology of muscle strength, mass and function in each country? We collaborate with a team currently planning extensive community-based population prevalence surveys in The Gambia, Zimbabwe and South Africa. We have a unique and time-limited opportunity to add to these surveys. We will collect data from questionnaires, DXA scans, muscle strength and function, physical performance and blood tests. We will quantify musculoskeletal multimorbidities including sarcopenia and determine associations with disability and HRQoL.
WP2: What are the clinical, nutritional and metabolic risk factors for low muscle strength, mass and function? Identifying risk factors for muscle impairment will aid understanding of mechanisms underlying muscle dysfunction. We will examine clinical, nutritional and metabolomic markers, and determine predictors of sarcopenia.
Findings fed-back to local communities, national health leads and policy makers.
This project grant offers a highly-cost effective opportunity, taking advantage of a funded research platform. This MRC investment would permit detailed and novel study of muscle in some of the most rapidly ageing populations in the world.