Associations between anthropometric indices and biological age acceleration in American adults: insights from NHANES 2009-2018 data.

Population aging has become a global phenomenon with significant implications for public health. Aging accelerates the development of age-related diseases, leading to increased social and economic burdens. Obesity further exacerbates these effects by increasing the risk of comorbidities and reducing life expectancy. This study examines the relationships between various anthropometric indices-A Body Shape Index (ABSI), Body Roundness Index (BRI), Body Mass Index (BMI), and Conicity Index (C-index)-and biological age acceleration, providing insights into the effectiveness of these indices in predicting biological aging. Data were sourced from the National Health and Nutrition Examination Survey (NHANES) 2009-2018, involving 22,921 participants after exclusions. Biological aging acceleration was assessed using Phenotypic Age Acceleration (PhenoAgeAccel) and Klemera-Doubal Method Age Acceleration (KDM-AA) algorithms. Associations between anthropometric indices and biological aging acceleration were evaluated using weighted multiple linear and logistic regression models, adjusted for potential confounders. Restricted Cubic Spline (RCS) regression explored non-linear associations. Receiver Operating Characteristic (ROC) curve analysis assessed the predictive capabilities of the anthropometric indices. Higher values of all four anthropometric indices (ABSI, BRI, BMI, and C-index) were significantly associated with increased biological aging acceleration (both PhenoAgeAccel and KDM-AA), even after adjusting for covariates. Significant non-linear relationships were observed in all four anthropometric indices. Subgroup analyses revealed robust associations across various demographics and health conditions. The area under the ROC curve (AUC) showed that the C-index exhibited the highest predictive capability for biological age acceleration. This study reveals significant associations between higher anthropometric indices and biological age acceleration in American adults, with the C-index being the most effective predictor.