Association between weight-adjusted-waist index and dyslipidemia among Japanese adult residents: a retrospective study

The Waist-adjusted Weight Index (WWI) is a novel anthropometric marker, its association with dyslipidemia in Asian populations remains unclear. This study examines the relationship between WWI and dyslipidemia in Japanese adults. Grounded in adipose tissue dysfunction and metabolic syndrome mechanisms, WWI, an index of central adiposity independent of body weight, serves as a biologically plausible predictor of dyslipidemia. We retrospectively analyzed 15,453 adults, undergoing health examination from Gifu Murakami Memorial Hospital (1994–2016). Logistic regression and fitted smooth curve analysis assessed WWI and dyslipidemia associations. Stratified analyses were performed based on sex, age, exercise, alcohol consumption, and smoking. WWI was positively associated with dyslipidemia (Adjusted OR = 1.30, 95% CI: 1.21–1.39). Risk increased across quartiles: Q2 (OR = 1.20), Q3 (OR = 1.36), Q4 (OR = 1.44). Smooth curve analysis indicated a nonlinear, accelerating increase. Associations were stronger in men, adults >60, smokers, drinkers, and those with insufficient exercise (P < 0.05). The findings support mechanistic links proposed by the adipose tissue disease theory and metabolic syndrome model, highlighting WWI as a simple, effective early screening tool for dyslipidemia. Prospective studies are needed to validate its predictive value in clinical and public health practice.