Most studies evaluate the potential health effects of one chemical at a time, but in reality, people are exposed to a mixture of chemicals every day. Studying a chemical mixture requires evaluating the effects of individual chemicals within the mixture, interactions between those chemicals, and the combined effect the mixture may have on human health.
Given this complexity, scientists need improved and innovative statistical methods to understand how exposure to real-world chemical mixtures may impact human health. The best methods are not yet clear.
To fill this gap, NIEHS created the Powering Research through Innovative Methods for mixtures in Epidemiology (PRIME) program, launching a funding opportunity in 2017 (RFA ES 17-001). Projects supported through PRIME will develop innovative statistical methods that move beyond the traditional approach of analyzing one chemical at a time and incorporate toxicological information into statistical models.
PRIME encourages team science. Experts in the fields of epidemiology, biostatistics, toxicology, data science, informatics, and related fields are working together to develop and compare these novel approaches. Methods will involve simulated, shared data, as well as real-world applications to human study populations.
The expected outcomes of PRIME include:
- Improving existing quantitative methods to better understand the complex relationships between environmental exposures and health outcomes.
- Stimulating new interdisciplinary methods for mixtures research in epidemiology.
- Comparing existing and novel approaches to identify the strengths and weaknesses across methods for various exposure and disease contexts.
- Developing informatics tools and related software for broad implementation of methods.
- Providing resources for the research community including publications, webinars, example datasets, and training.
Funded PRIME Projects
PRIME grantees are studying how exposure to mixtures of metals, pesticides, endocrine disrupting chemicals, persistent organic pollutants, and air pollution affect health. Some researchers will also examine how non-chemical exposures, like stress and nutrition, may amplify or protect against the adverse health effects of a chemical mixture.
PRIME projects will develop novel statistical approaches that:
- Allow researchers to discover the biological pathways that link an exposure to a disease.
- Determine which exposures within a mixture are most harmful, and how the mixture as a whole influences health – this will help risk assessors define acceptable values of exposure for mixtures of environmental chemicals.
- Incorporate information on chemical toxicity to provide biological context for exposures.
- Incorporate the timing of exposure and capture critical windows of development when individuals are more susceptible to exposures.
- Link unrelated datasets to capture variability in exposures and outcomes across space and time.
Importantly, PRIME researchers will share their newly developed statistical methods and software with the wider environmental health science research community to help advance mixtures research.
Bonnie R. Joubert, Ph.D.
Health Scientist Administrator, Epidemiology
P.O. Box 12233Mail Drop K3-12Durham, N.C. 27709
Leroy Worth Jr, Ph.D.
Scientific Review Officer
P.O. Box 12233Mail Drop K3-03Durham, N.C. 27709