Association Between Ethylene Oxide Exposure and Cognitive Function in US Older Adults: NHANES 2013-2014.

Background: Ethylene oxide (EO) is a common organic compound associated with many adverse health outcomes. However, studies exploring the association between EO exposure and cognitive function are limited.

Objective: This study aims to examine this relationship between EO exposure and cognition in older adults.

Methods: This study enrolled 438 older adults from the National Health and Nutrition Examination Survey (NHANES) 2013-2014 cycle. EO exposure was quantified by the measurements of blood hemoglobin adducts of ethylene oxide (HbEO) concentrations. Cognitive function was measured by the Consortium to Establish a Registry for Alzheimer's Disease battery (CREAD), the Animal Fluency test (AFT), and the Digit Symbol Substitution Test (DSST). Linear regression model, generalized additive model, and smooth curve fitting were applied to examine the linear and nonlinear relationship between EO exposure and cognitive function. We used a two-piecewise linear regression model to detect the threshold effect of EO exposure on cognitive function.

Results: Participants with higher HbEO levels had lower AFT and DSST scores than those with lower HbEO levels. After adjusting for all confounding factors, log2-transformed HbEO levels were negatively associated with AFT score. The smooth curve fitting demonstrated the nonlinear relationship between EO exposure and DSST scores. When log-2 transformed HbEO levels >4.34 pmol/g Hb, EO exposure was negatively associated with DSST score.

Conclusions: This study indicated that high levels of HbEO were associated with cognitive decline in US older adults. Future cohort studies are needed to verify our findings.