Nonlinear association between waist-to-height ratio and Alzheimer's disease among middle-aged and older adults: A cross-sectional study from NHANES.

BackgroundThe association between waist-to-height ratio (WHtR) and Alzheimer's disease (AD) remains unclear in the general population.ObjectiveThis study aimed to investigate the relationship between WHtR and AD using data from the nationally representative National Health and Nutrition Examination Survey (NHANES).MethodsThis cross-sectional study included participants aged ≥45 years from NHANES. Weighted multivariable logistic regression, restricted cubic spline (RCS), subgroup, and sensitivity analyses were performed to evaluate the association between WHtR (scaled by 10) and AD.ResultsHigher WHtR was significantly associated with greater odds of AD after adjustment for potential confounders (OR = 1.30, 95% CI: 1.18-1.42, p < 0.001). Significant interactions were observed for age (p for interaction = 0.017) and physical activity (p for interaction = 0.02). RCS analysis revealed a significant nonlinear U-shaped association between WHtR and AD (p for nonlinearity = 0.005), with the lowest odds observed at a WHtR value of 5.46 on the 10-fold scale. Sensitivity analyses showed generally consistent results.ConclusionsHigher WHtR was significantly associated with greater odds of AD among middle-aged and older adults. A nonlinear U-shaped association was also observed, suggesting that both lower and higher WHtR levels may be associated with increased odds of AD. Further prospective studies are warranted to confirm these findings.