Association between a body shape index and low back pain: a cross-sectional study highlighting gender-specific differences in NHANES data

This study aimed to investigate the association between A Body Shape Index (ABSI) and low back pain, with a focus on gender and age differences, using cross-sectional data from the NHANES database. A total of 14,268 participants were included from four NHANES cycles (1999–2004 and 2009–2010). Low back pain was assessed based on self-reported pain over the past three months, and ABSI was calculated using waist circumference, height, and weight. Multivariate logistic regression models were used to evaluate the association between ABSI and low back pain, adjusting for potential confounders. Restricted cubic spline (RCS) analysis was conducted to assess non-linear relationships, and subgroup analyses were performed based on gender, age and BMI. Higher ABSI was significantly associated with an increased risk of low back pain (OR for highest quartile = 1.27, 95% CI: 1.07–1.50, p = 0.008). RCS analysis indicated a linear relationship between ABSI and low back pain, with the risk significantly rising when ABSI exceeded 0.85. Subgroup analyses revealed that this association was more pronounced in males (OR = 25.89, 95% CI: 3.11-215.86, p = 0.004) and participants aged ≥ 60 years (OR = 11.11, 95% CI: 2.61–47.26, p = 0.002), while no significant association was observed in females. The ABSI was associated with low back pain. This association was more prominent in males and older adults. Our findings suggest that ABSI may provide a more nuanced understanding of low back pain risk, particularly in populations with abdominal obesity. Further studies are needed to explore the underlying mechanisms and potential clinical applications of ABSI in low back pain risk assessment.