Association Between Weight-Adjusted Waist Index and the Prevalence of Low Back Pain: A Cross-Sectional Observational Study from National Health and Nutrition Examination Survey

BACKGROUND: The weight-adjusted waist index (WWI) is a novel obesity index that is calculated as the waist circumference (WC) divided by the square root of body weight (kg). Previous studies have revealed that higher body mass index (BMI) and WC increase the risk of low back pain (LBP). However, no research explores the relationship between WWI and LBP. METHODS: Data utilized in this cross-sectional study were drawn from the National Health and Nutrition Examination Survey. Three logistic regression models were used to evaluate the association between WWI and LBP. Stratified analysis was applied to assess the stability of the results. Receiver-operating characteristic (ROC) curves were employed to visually assess and compare the predictive effectiveness of WWI, BMI, WC, and weight on LBP. RESULTS: A significant positive correlation was observed between WWI and LBP, model 1 (odds ratio [OR] = 1.222,95% confidence interval (95% CI) [1.164, 1.283], P < 0.0001), model 2 (OR = 1.187, 95% CI [1.118, 1.261], P< 0.0001), and model 3 (OR = 1.129, 95% CI [1.056, 1.207], P< 0.001). Relative to the Q1, Q3 (model 1 (OR = 1.241, 95% CI [1.114, 1.382], P < 0.001), model 2 (OR = 1.192, 95% CI1.310], P = 0.047)) and Q4 (model 1 (OR = 1.524, 95% CI [1.341, 1.733], P< 0.0001), model 2 (OR = 1.422,95% CI [1.233, 1.640], P< 0.0001), model 3 (OR = 1.333, 95% CI [1.149, 1.547], P < 0.001)) all showed a significant positive correlation between them. The area under the receiver-operating characteristic curve (AUC) for WWI is 0.5447536, the AUC for BMI is 0.5466724, and the AUC for WC and weight is 0.5501341 and 0.5376615, respectively. CONCLUSIONS: This cross-sectional study revealed a significant positive association between WWI and LBP, but WWI did not show better predictive efficacy than BMI and WC.