What does the exposome refer to in toxicology?

• A. The totality of environmental exposures across the lifespan, starting at birth; important for risk communication.
• B. The totality of environmental exposures from conception onward; important for understanding cumulative risk and individual susceptibility.
• C. A set of exposure metrics collected in a lab assay.
• D. The genetic makeup that determines susceptibility.

Answer: (B)

Exposome means the total environmental exposures a person experiences from conception onward, across the entire life, and how those exposures interact with internal processes to influence health. In toxicology, this broad view captures chemical, physical, biological agents, plus lifestyle, nutrition, stress, and other factors that can affect risk over time. It helps explain why individuals respond differently to the same chemical: cumulative risk accumulates across the lifespan, and susceptibility varies with genetics, age, health status, and when exposures occur. Prenatal exposures are part of the exposome, so starting at conception provides the most complete picture. The other ideas—focusing only on birth, on isolated lab metrics, or on genetics—don’t describe the whole environmental context that the exposome encompasses.