Supplementary Material for: Life's Crucial 9 Score and Cognitive Performance in Older Adults: The Mediating Role of Biological Aging

Abstract
Background: Cognitive decline is a pressing public health concern in older adults. The recently proposed Life’s Crucial 9 (LC9) score, which integrates cardiovascular and mental health metrics, may offer a novel framework for predicting cognitive impairment.
Methods: We analyzed data from 2,180 participants aged ≥ 60 years from 2011 to 2014 National Health and Nutrition Examination Survey (NHANES). LC9 was computed based on eight cardiovascular health metrics and depressive symptoms. Cognitive performance was assessed using the Animal Fluency Test (AFT), Consortium to Establish a Registry for Alzheimer’s Disease (CERAD) test, and Digit Symbol Substitution Test (DSST). Biological Age (BA) and Biological Age Acceleration (BAcel) were derived using a validated algorithm. Weighted logistic regression, receiver operating characteristic (ROC), restricted cubic spline (RCS) models, and mediation analyses were performed to evaluate the associations.
Results: Higher LC9 scores were significantly associated with lower odds of poor performance on the AFT (P = 1.5 x 10-2) and DSST (P = 1.4 x 10-2), but not CERAD (P = 1.2 x 10-1). ROC analysis showed that LC9 significantly outperformed Life’s Essential 8 (LE8) in predicting low AFT and DSST performance (AUC: 0.599 vs. 0.588 for AFT; 0.632 vs. 0.614 for DSST). The RCS models indicated no statistically significant nonlinear relationship between the LC9 and cognitive performance. Mediation analysis revealed that BA and BAcel accounted for 7.48% and 4.53% of the total effect of LC9 on DSST performance, respectively. The subgroup and sensitivity analyses confirmed the robustness of these findings.
Conclusion: LC9 is significantly associated with cognitive performance in older adults. This association with DSST is partially mediated by biological aging.