LAUSR

The development of low back pain (LBP) is often associated with obesity and sarcopenia. However, the mechanisms of this association remain unclear. To clarify this, we measured circulating levels of a selected panel of soluble factors, presumably involved in obesity and sarcopenia pathogenesis, and correlated them with several LBP-related characteristics, taking into account body composition and other relevant covariates. In the cross-sectional study of 1078 individuals, we collected data on self-reported LBP, body composition (including fat and skeletal muscle mass) assessed by the bioimpedance method and anthropometrically, and measured plasma levels of several cytokines by ELISA. In the statistical analysis, we took into account familial composition of the sample and possible putative genetic effects. We report that LBP-affected individuals were significantly older, with increased obesity and decreased skeletal mass, respectively, compared with the non-affected group. In univariate analyses, plasma concentrations of Growth and differentiation factor 15 (GDF-15), leptin, chemerin and follistatin were found significantly elevated in the LBP-affected groups (with or without sciatic pain) and were highly significantly (p < 0.001) associated with other LBP-related phenotypes, specifically, disease duration, disability and physician consults. However, after adjustment for one another, age, sex, body composition and putative genetic factors, the only associations between GDF-15 and LBP disability and medical consulting phenotypes, remained significant. In conclusion, we report for the first time, a significant and independent association between plasma GDF-15 concentrations and LBP-associated disability. Longitudinal studies are needed to determine whether GDF-15 could be a novel therapeutic target for prevention and/or treatment of LBP.