Combined Exposures and Mixtures Research: An Enduring NIEHS Priority.

Area of Science:

• Environmental Health Sciences
• Toxicology
• Epidemiology

Background:

• The National Institute of Environmental Health Sciences (NIEHS) prioritizes research on health effects from combined exposures to chemical and nonchemical stressors.
• Mixtures research has been guided by expert workshops since 2011, focusing on prioritization, data translation, collaboration, assessment approaches, similarity methods, systems-based evaluation, and data management.

Purpose of the Study:

• To describe NIEHS-supported research on mixtures and combined exposures over the last decade.
• To identify key areas for future research in mixtures science.

Main Methods:

• Review of intramural and extramural mixtures research projects.
• Incorporation of diverse chemicals (e.g., polycyclic aromatic hydrocarbons, personal care products, wildfire emissions) and nonchemical stressors (e.g., socioeconomic factors, social adversity).
• Development of statistical methods for epidemiological analysis and translational projects using in vitro and in vivo models.

Main Results:

• Significant progress in developing statistical methods for evaluating multiple chemical exposures in epidemiology.
• Advancements in translational mixtures research integrating in vitro and in vivo models.
• Diverse research incorporating various chemicals and nonchemical stressors across multiple diseases.

Conclusions:

• Further research is needed to enhance mixtures data integration and understand interactions between chemical and nonchemical stressors.
• Resolving the geospatial and temporal aspects of mixture exposures is crucial.
• Continued mixtures research is vital for cumulative impact assessments, environmental justice, and climate change adaptation.