AUTHOR=Deng Yu , Lin Xuechun , Zhou Jie , Li Mengchi , Fu Zhenmei , Song Dan 

TITLE=Concurrent serum lead levels and cognitive function in older adults

JOURNAL=Frontiers in Neuroscience

VOLUME=Volume 17 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/neuroscience/articles/10.3389/fnins.2023.1180782

DOI=10.3389/fnins.2023.1180782

ISSN=1662-453X

ABSTRACT=ABSTRACT
Introduction: In this study, we investigated the relationship between serum lead level and cognitive functioning in a sample of older adults in the US.
Method: Using the National Health and Nutrition Examination Survey (NHANES) 2011-2013, a total of 768 older adults aged ≥60 were included in the analysis. Lead concentrations in whole blood samples were assessed using mass spectrometry. We used the immediate and delayed memory portions of the Consortium to Establish a Registry for Alzheimer's Disease Word Learning Subtest (CERAD-WL), the Animal Fluency Test (AFT), and the Digit Symbol Substitution Test (DSST) to assess participants’ cognitive performance. Using sample averages and standard deviations (SDs), we computed test-specific as well as global cognition z-scores. In order to assess the relationships between the quartiles of serum lead level and cognitive performance, multiple linear regression models were built and adjusted for covariates including age, sex, race/ethnicity, education, depressive symptoms, alcohol usage, and body mass index. 
Results: The average age of the participants was 69.6 (SD 6.6). The participants were about half female (52.6%), non-Hispanic White (52.0%), and (51.8%) had completed at least some college. They had an average serum lead concentration of 1.8 g/dL (SD 1.6). The results of multiple linear regression using individuals in the lowest serum lead quantile as a reference group revealed that serum lead level was not associated with test-specific (CERAD-WL, AFT, and DSST) or global cognitive z-scores. 
Conclusions: In older persons, concurrent serum lead concentration is not related to cognitive performance. Early or continuous lead exposure may exert a greater effect on the etiology of accelerated cognitive decline in old age.