Inflammatory Mediators and Pain in the First Year After Acute Episode of Low-Back Pain in Elderly Women

Objective The aims of this study were to determine the course of plasma levels of inflammatory mediators (interleukin 6 [IL-6], tumor necrosis factor α [TNF-α], soluble TNF receptor 1 [sTNF-R1]) and the severity of low-back pain (LBP) over 6 to 12 months after an acute episode of LBP in elderly women and to establish an association between inflammatory mediators and LBP recovery. Design This was a longitudinal study of a subsample (155 elderly women with acute LBP, aged ≥65 years) of the international Back Complaints in the Elders cohort study. Plasma levels of IL-6, TNF-α, and sTNF-R1 were measured using enzyme-linked immunosorbent assays and pain severity using the numerical pain scale. Results There was a decrease in the severity of LBP (P = 0.033) and in the levels of IL-6 and TNF-α (P < 0.001) and an increase in sTNF-R1 (P < 0.001) in the first year after an acute episode of LBP. The probability of occurrence of pain relief at the 12-month follow-up was 2.22 times higher in elderly women who had low levels of IL-6 (<1.58 pg/mL) at baseline. Conclusions Our findings showed a relationship between inflammation and LBP by establishing that low IL-6 plasma levels preceded outcome (LBP recovery), supporting the concept that proinflammatory cytokines promote pain.