A Framework for Cumulative Risk Assessment: Exploring the Carcinogenic Effects of Chemical Mixtures

Open in a separate window Humans are commonly exposed to mixtures of chemicals in their environments, rather than to one compound at a time. Accordingly, researchers have long been interested in the complex task of studying how mixtures affect disease end points.1 Cynthia Rider and colleagues recently proposed in Environmental Health Perspectives2 a research program on mixtures and cancer based on the key characteristics of carcinogenic chemicals.3 “We wanted to apply what we have learned from studying outcomes with shorter exposure periods to a more complex scenario,” says Rider, a toxicologist at the National Institute of Environmental Health Sciences and first author of the new paper. “Because cancer results from the cumulative impact of multiple low-dose hits in several pathways during a long period of latency, the analysis of mixture effects is especially challenging.” Open in a separate window Although people are exposed to many chemicals over their lifetimes—in food, water, personal care products, air, and other media—toxicology has historically studied agents individually. The authors of a new commentary recommend strategies for studying exposures to chemical mixtures. Image: © iStock/NoSystem Images.