Blood Inflammation Indexes Mediate the Association Between Weight-Adjusted-Waist Index and Cognitive Function Among Older Adults in the United States.

OBJECTIVES

This study explored the relationship between the weight-adjusted-waist index (WWI) and cognitive function among older individuals in the United States (US) and assessed whether blood inflammation indexes potentially mediate the association between WWI and cognitive function.

METHODS

The National Health and Nutrition Examination Survey data from 2011 to 2014 were collected. The WWI (waist circumference divided by the square root of bodyweight) was calculated, and cognitive performance was assessed using the Consortium to Establish a Registry for Alzheimer's Disease Word Learning (CERAD-WL) test, Delayed Recall (CERAD-DR) test, Animal Fluency Test (AFT), and Digit Symbol Substitution Test (DSST). Test-specific and global cognition z-scores were created. The evaluated blood inflammation indexes included systemic inflammatory response index (SIRI), systemic immune-inflammation index (SII), and neutrophil to lymphocyte ratio (NLR). Generalized linear regression models and mediation analysis were used to quantify the association.

RESULTS

After adjusting for covariates, the results of generalized linear regression analysis showed a significant negative connection between WWI and CERAD-WL (β = -0.47, 95% CI: -0.87, -0.07) and DSST (β = -1.59, 95% CI: -2.45, -0.72) among the 2026 participants. WWI correlated positively with SII, SIRI, and NLR (p < 0.05), whereas SIRI and NLR demonstrated a negative association with CERAD-WL and DSST (p < 0.05). The relationship between WWI and CERAD-WL performance was partially mediated by SIRI/NLR.

CONCLUSIONS

A negative association was observed between cognitive performance and WWI. The blood inflammation indexes were found to partially mediate the relationship between WWI and cognition. These findings warrant further evaluation in different populations.