Anthropometric evaluation of trunk parameters in chronic low back pain: a comparative study with age- and sex-matched controls

Low back pain (LBP) is a complex and multifaceted condition influenced by factors such as obesity, skeletal deformities, and abdominal muscle dysfunction, though the exact occurrence and interrelationships of these factors remain unclear. The aim of this study is to investigate the anthropometric differences in the trunk between LBP sufferers and healthy controls, exploring the association with obesity and respiratory function. This cross-sectional study evaluated 50 adult patients with chronic LBP and 50 age- and sex-matched healthy controls. Anthropometric parameters including waist circumference, waist-to-height ratio, respiratory amplitude, sternum length, and the distance between the xiphoid process and pubic symphysis were measured, and the occurrence of diastasis recti was investigated. Group differences were analyzed using independent t-tests and chi-square tests. The LBP group exhibited significantly larger waist circumferences (p = .016), higher waist-to-height ratios (p = .004), and reduced respiratory amplitudes (p < .001) compared to controls. No significant differences were observed in sternum length and xiphoid process-pubic symphysis distance. The study found no significant link between LBP and diastasis recti, but post-hoc analysis indicated that larger waist sizes are associated with a 10.7% higher likelihood of diastasis. LBP is significantly associated with increased waist circumference and waist-to-height ratio, as well as decreased respiratory amplitude, highlighting the potential role of obesity and compromised respiratory function in LBP. No significant differences were observed in measures related to postural development, such as sternum length and the distance between the xiphoid process and the pubic symphysis. Although our findings highlight associations between LBP and increased waist circumference, waist-to-height ratio, and reduced respiratory amplitude, the cross-sectional nature of this study does not allow for causal conclusions. These results suggest areas for further research into whether targeted interventions focusing on weight management and respiratory function training could benefit individuals with LBP.