Exposure to Phthalate Metabolite Mixtures as a Risk Factor for Low Muscle Mass: Insights From the National Health and Nutrition Examination Survey (2011-2018).

OBJECTIVES

Ambient contamination may contribute to low muscle mass development, yet evidence regarding the detrimental impacts of phthalate metabolites on muscle wasting is scarce. This study aimed to investigate the relationship between individual and collective phthalate metabolite exposures and low muscle mass occurrence and assess the mediating role of body mass index (BMI).

DESIGN

Cross-sectional study.

SETTING AND PARTICIPANTS

Data from 3028 individuals (aged ≥20 years) who participated in the National Health and Nutrition Examination Survey (2011-2018) were examined.

METHODS

All participants provided data regarding 9 urinary phthalate metabolites, urinary creatinine levels, BMI, dual-energy X-ray absorptiometry measurements, and other pertinent covariates. Survey-weighted logistic regression, weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR) models were used to investigate the relationships between individual and collective chemical exposures and low muscle mass. Mediation analysis was conducted to examine the potential mediating effect of BMI in these associations.

RESULTS

Among the participants, 7.8% exhibited low muscle mass. A strong correlation was observed between monoethyl phthalate (MEP) and low muscle mass occurrence, with significant associations in the highest quartile for MEP and mono-n-butyl phthalate (MnBP). The WQS index was significantly linked to low muscle mass incidence, with MEP, MnBP, and monobenzyl phthalate (MBzP) emerging as the predominant contributors. The BKMR model revealed a positive overall trend between co-exposure to multiple phthalates and low muscle mass risk. Mediation analysis indicated that BMI accounted for 26.11% of the total effect between MBzP and low muscle mass.

CONCLUSIONS AND IMPLICATIONS

Exposure to various phthalate metabolite combinations appears to elevate the risk of low muscle mass, and this association is partially mediated by BMI. These findings warrant further investigation to confirm their validity. Understanding the biological mechanisms through which these compounds operate is essential to clarify their role in the progression of low muscle mass.