Low-grade systemic inﬂammation and musculoskeletal pain
Our understanding of the multiple systems and their interactions that contribute to musculoskeletal pain has evolved considerably in recent years. There is considerable interest in the role of the immune system in both acute and persistent musculoskeletal pain states. Systemically elevated levels of proinflammatory cytokines and chemokines have been revealed in people with musculoskeletal pain. In various musculoskeletal disorders this low-grade inflammation has been demonstrated , such as low back pain, neck pain and radicular pain. Moreover, a first study suggests that inflammatory reactions in the acute phase of low back pain may also be related to recovery.
Levels of inflammatory biomarkers are influenced by multiple factors such as demographic variables, psychological factors and various diseases in people with and without musculoskeletal pain. These factors may increase systemic cytokine concentrations via their direct or indirect action on immune cells and the subsequent release of inflammatory cytokines and chemokines. Adaptation to potential confounders is essential to determine the degree of association between low grade systemic inflammation, musculoskeletal pain and recovery.
In a study in people with multisite persistent pain the importance of correction for confounders in the measurement of systemic cytokine levels is illustrated. These studies show that the association between inflammatory biomarkers and the presence of musculoskeletal pain may be disrupted by sociodemographic variables, lifestyle and disease, and anxiety and depression.
Levels of inflammatory biomarkers are likely to arise from a complex interaction between the central nervous system, the immune system, the endocrine system, psychological factors, sociodemographic factors, lifestyle and behavior.