Relationship between the levels of metabolites of organophosphate flame retardants in adult urine and NAFLD

Abstract

Objective

Based on the data from NHANES database, the relationship between the levels of metabolites of five organophosphate flame retardants (OPFRs) in adult urine and non-alcoholic fatty liver disease (NAFLD) was analysed to provide scientific foundation for the prevention and control of the development of NAFLD.

Methods

Data from 3287 adults (NHANES 2011–2018) were analysed, and the presence of NAFLD was determined based on the fatty liver index. R4.3.2 software was utilized to explore the correlation between the levels of metabolites of urinary OPFRs and NAFLD. The gWQS package in R was employed to perform weighted quantile sum regression analysis. Subjects were further stratified by sex to conduct binary Logistic regression analysis and weighted quantile sum regression analysis.

Results

In sex-stratified logistic regression analyses, higher urinary bis(1-chloro-2-propyl) phosphate (BCPP) levels were positively associated with NAFLD in men, with participants in the highest exposure category of log-transformed BCPP concentrations showing an increased risk of NAFLD (OR = 4.117, 95% CI: 1.160-14.606). No other urinary OPFR metabolites showed significant positive associations with NAFLD. WQS regression further suggested that BCPP, and to a lesser extent di-n-butyl phosphate (DBUP), were the main contributors to the OPFR mixture effect on NAFLD, particularly among men.

Conclusion

BCPP and DBUP may influence the development of NAFLD, and BCPP appears to be closely associated with NAFLD in men, suggesting that it may represent a potential risk factor for NAFLD.

Graphical abstract