Hypertension, diabetes and dyslipidemia exhibit high prevalence rates in the population and frequently coexist as comorbidity within individuals. The weight-adjusted waist index (WWI) represents a novel obesity assessment metric; however, its association with the comorbidity of the three diseases remains inadequately studied.

To investigate the association and predictive role of WWI for the comorbidity of hypertension, diabetes and dyslipidemia among community-dwelling adults.

Based on the Chronic Disease and Risk Factor Surveillance, a cross-sectional survey was conducted using multi-stage random sampling method among permanent residents aged ≥18 years in Bao'an District from October to December 2023. Data were collected through questionnaires, physical examinations, and laboratory biochemical tests, based on which the WWI was calculated, and the comorbidity of hypertension, diabetes and dyslipidemia was documented. Logistic regression was employed to analyze the association between WWI and the comorbidity of the three diseases. Restricted cubic spline (RCS) analysis was applied to explore the dose-response relationship between WWI and the comorbidity. Stratified analyses were conducted by sex, age and BMI, and interactions were explored. Receiver operating characteristic (ROC) curves were used to evaluate and compare the predictive performance of WWI, BMI and waist circumference (WC) for these diseases comorbidities, utilizing DeLong's test comparing differences in area under the curve (AUC).

A total of 1 882 individuals were surveyed, after excluding participants with missing key indicators such as height, body mass and WC, a final total of 1 846 participants were included in the analysis. The comorbidity rates of hypertension, diabetes and dyslipidemia was 17.06% (315/1 846). The Logistic regression analysis results indicated that, after full adjusting for covariates, each 1-unit increase in WWI was associated with a 174% increased risk of the comorbidity (OR=2.74, 95%CI=2.08-3.59, P<0.05). Compared with the Q1 group (WWI<9.69 cm/), the risk of comorbidity increased progressively in the Q2 (9.69 cm/ ≤WWI<10.19 cm/), Q3 (10.19 cm/ ≤WWI<10.66 cm/), and Q4 (WWI≥10.66 cm/) groups, with OR values of 2.62 (95%CI=1.26-5.42, P<0.05), 4.68 (95%CI=2.31-9.48, P<0.05), and 8.09 (95%CI=3.95-16.56, P<0.05), respectively. RCS analysis revealed a significant linear dose-response relationship between WWI and the risk of comorbidity (P_overall<0.001, P_nonlinear=0.079). Subgroup analysis revealed that, with the exception of the BMI<24.00 kg/m² stratum, individuals in the highest WWI quartile (Q4) exhibited a significantly increased risk of the comorbidity across the following strata: male, female, age<45 years, age≥45 years and BMI≥24.00 kg/m² (all P<0.05). Interaction analysis showed a significant interaction between WWI and age, with a stronger association between WWI and the comorbidity in the <45 years group compared to the ≥45 years group (P=0.003). The ROC analysis yielded that among males, the AUC (95%CI) for WWI, BMI and WC in predicting the risk of the comorbidity were 0.742 (95%CI=0.705-0.778), 0.705 (95%CI=0.667-0.742), and 0.738 (95%CI=0.702-0.774), respectively. Among females, the corresponding AUC (95%CI) for WWI, BMI and WC were 0.806 (95%CI=0.768-0.844), 0.717 (95%CI=0.669-0.765), and 0.804 (95%CI= 0.766-0.842). In the female population, WWI demonstrated significantly higher predictive accuracy than BMI (Z=-3.134, P=0.002).

WWI exhibits a significant positive and linear dose-response association with comorbidity of the three diseases, demonstrating favorable predictive efficacy. As a novel obesity metric, WWI offers valuable insights for the early prevention and intervention targeting this comorbidity.