Association between Weight-Adjusted Waist Index and Chronic Pain in U.S. adults: a Cross- Sectional Study

Background Chronic pain is associated with significant levels of disability and is widely considered an important public health problem. Current evidence implicates a significant link between chronic pain and obesity, along with associated metabolic dysfunctions. The weight-adjusted waist index (WWI) is an innovative measure for obesity. This study aims to explore the association between WWI and chronic pain among American adults. Methods This study used data from the 1999–2004 National Health and Nutrition Examination Survey (NHANES). Chronic pain was defined as self-reported pain lasting for ≥ 3 months in the past year. Weighted multivariate linear regression and smoothed curve fitting were conducted to investigate the linear associations between WWI and chronic pain. Threshold effects were determined using a two-part linear regression model. Subgroup analyses were conducted to investigate factors influencing the relationship between WWI and chronic pain. Results Among the 12,694 participants, 1,856 (14.62%) experienced chronic pain. After complete adjustment, every unit increase in WWI correlated with a 10% higher odds of chronic pain prevalence (OR 1.10, 95% CI 1.01–1.19, P  = 0.036). Individuals in the highest WWI quartile (11.54–15.52) cm/\(\:\sqrt{\text{k}\text{g}}\) had a 31% increased odds of chronic pain prevalence compared to those in the lowest quartile (7.90–10.36) cm/\(\:\sqrt{\text{k}\text{g}}\) (OR 1.31, 95% CI 1.08–1.60, P  = 0.016). The positive association between WWI and chronic pain remained persisted across all subcategories except for race. The saturation effect between WWI and chronic pain was observed, with the inflection point at 11.88 cm/\(\:\sqrt{\text{k}\text{g}}\) for all participants and 11.79 cm/\(\:\sqrt{\text{k}\text{g}}\) for females. Conclusions Our research demonstrated a notable positive association between WWI and chronic pain. These findings help public health officials better understand of importance of controlling abdominal obesity in alleviating chronic pain, aid in the development and evaluation of pain management programs, and develop optimal interventions to diagnose and treat chronic pain.