Deciphering the Causal Relationships Between Low Back Pain Complications, Metabolic Factors, and Comorbidities.

PURPOSE: Low back pain (LBP) is one of the major disabling health conditions in aging societies presenting significant cost burdens to health and social care systems. Its complications and associated disability are often accompanied by mental disorders, metabolic comorbidities, changed body composition, and inflammation. However, their mutual relationships in LBP-associated disability remain unclear. METHODS: In the present case-control study, a self-report validated questionnaire was used to collect LBP disability data in an ethnically homogeneous Israeli Arab sample (489 males and 589 females). Body composition parameters were assessed through bioelectrical impedance analysis and plasma levels of soluble markers by EISA. Comorbidity status was assessed in personal interview and from the individual medical files. RESULTS: Our mixed multiple regression analysis identified that GDF-15 (β = 0.160, p = 2.95×10-8), vaspin (β = 0.085, p = 0.003), follistatin (β = 0.076, p = 0.001), extracellular water (β = 0.096, p = 0.001), waist hip ratio (β = 0.072, p = 0.009), mental disorders (β = 0.077, p = 0.001), and metabolic comorbidities (β = 0.059, p = 0.02) were significantly associated with LBP disability scores, when controlling for age and sex effects. Additive Bayesian network modelling further suggests that LBP disability appears to be directly influenced by age, sex, GDF-15, and extracellular water, and indirectly by mental and metabolic disorders, waist-hip ratio, and follistatin. LBP, in turn, seems to affect the vaspin levels directly. CONCLUSION: Our data suggest the existence of a complex, age-associated, and probably hierarchical, relationship between LBP disability and mental and metabolic disorders, inflammation-related soluble markers, and body composition parameters.