Muscle composition as a possible biomarker for chronic back pain

edited by Lisa Lock, reviewed by Andrew Zinin

Back pain affects more than 80 million people in Europe and is the most common cause of disability. If the pain persists for more than three months, it is referred to as chronic back pain, which not only reduces the quality of life of affected individuals, but also places a heavy financial burden on the health care system.

Researchers at the Technical University of Munich (TUM) have investigated the relationship between muscle quality and chronic back pain using whole-body magnetic resonance imaging (MRI) and artificial intelligence (AI) methods.

The analysis of MRI data from approximately 30,000 participants in the German National Cohort (NAKO) showed that a higher proportion of adipose tissue in the back muscles and lower muscle mass were associated with chronic back pain.

The study, published in The Lancet Regional Health – Europe, underlines that assessing muscle composition could be helpful in evaluating the risk of chronic back pain.

“Back pain, especially in its chronic form, is a multifactorial problem and often co-occurs together with other musculoskeletal disorders. Identifying modifiable factors such as physical activity, diet and everyday habits is not only essential for therapy management, but also offers enormous potential for primary prevention. Radiological whole-body imaging, using MRI, allows the precise quantification of individual body compartments through AI-supported models.

“The focus of our investigation was the skeletal muscles in the back area. These muscles are not only strongly influenced by lifestyle factors but, according to our hypothesis, also show altered composition in chronic back pain,” reports Dr. Sebastian Ziegelmayer, scientist and physician at TUM University Hospital.

The whole-body MRI data of 27,518 NAKO participants aged between 19 and 74 were analyzed. 21.8% reported chronic back pain. Using MRI-based, AI-supported muscle segmentation, the back muscles were delineated and classified into fatty and non-fatty components. In the statistical analysis, the researchers adjusted for various factors such as age, gender, physical activity and comorbidities (diabetes, dyslipidemia, osteoporosis and osteoarthritis), all of which have been proven to influence muscle composition.

The researchers’ analyses showed that a higher level of intermuscular adipose tissue was associated with an increased likelihood of chronic back pain, whereas greater muscle mass was linked to a lower likelihood. The study also provides evidence that physical activity—at a level consistent with World Health Organization (WHO) recommendations of 150 minutes of moderate to strenuous exercise per week—correlated with the lowest incidence of back pain, while both too little and too much exercise increased the risk.

“However, our work also has limitations: The study design, which is based on data from a single time point, only allows us to draw conclusions about associations. Especially for back pain, which can be influenced by many factors, further studies are needed to investigate causal relationships and underlying mechanisms in more detail,” says Ziegelmayer.

“Muscle composition is often neglected in routine diagnostics, but it appears -particularly in combination with other factors such as lifestyle, psychological and biomechanical aspects- to be a possible piece of the puzzle for chronic back pain. We hope that our results will provide an impulse for further studies, enabling the development of individualized management strategies and thereby reducing the economic and social burden of chronic back pain.”

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