Association between pain intensity and body composition in adults with chronic non-specific low back pain: A systematic review and meta-analysis

Introduction: This systematic review and meta-analysis evaluated the association between pain intensity and different body composition measures in adults suffering from chronic non-specific low back pain (CNLBP).
Methods: A systematic literature search across five databases—PubMed, Embase, CINAHL, Web of Science, and the Cochrane Library—was conducted. It identified observational studies published until January 2024. A meta-analysis was conducted incorporating a random-effects approach with Fisher's Z transformation. A critical appraisal of the included studies' quality was conducted.
Results: Twenty-two studies were included. Of those, 20 were meta-analyzed, revealing positive, very weak correlations between pain intensity and body mass index (r = 0.11; 95% CI: 0.04 to 0.18), waist–hip ratio (r = 0.10; 95% CI: 0.14 to 0.34) and waist circumference (r = 0.09; 95% CI: 0.28 to 0.44). Not pooled study findings (e.g., hip circumference and body fat percentage) were narratively summarized, revealing 13 positive and four negative associations between pain intensity and body composition measures. Studies showed a substantial risk of bias due to unadjusted confounding factors and limited transferability of findings.
Conclusion: This systematic review and meta-analysis provided very low-quality evidence for a positive, very weak association between pain intensity and body composition measures in adults with overweight and obesity suffering from CNLBP. The included studies had a substantial risk of bias due to their observational and crosssectional study designs, which prevents recommendations for clinical practice. Randomized controlled trials are needed to investigate the causal effect of interventions on body composition measures and pain intensity.