exposome

The exposome is a concept that encompasses all environmental exposures an individual encounters from conception onward, highlighting how non-genetic factors contribute to health and disease. The term was introduced by Christopher Wild in 2005 as a complement to the genome, intended to describe the totality of lifetime environmental influences and their biological effects.

Researchers often divide the exposome into external and internal domains. The external exposome includes physical, chemical, and social factors such as air and water pollutants, diet, occupational exposures, radiation, infectious agents, psychosocial stress, lifestyle choices (smoking, alcohol, physical activity), and socioeconomic status. The internal exposome comprises biological responses to these exposures, including the metabolome, proteome, transcriptome, epigenome, microbiome, inflammatory and hormonal signals, and other endogenous processes that reflect exposure and susceptibility.

Measuring the exposome relies on exposomics, using untargeted and targeted biomonitoring, high-resolution mass spectrometry, metabolomics, and other omics approaches to detect known and unknown exposures. Wearable sensors, longitudinal sampling, and biobanking support exposure assessment. Analyses such as exposome-wide association studies (ExWAS) seek associations between exposure profiles and health outcomes, often focusing on exposure trajectories and critical windows of development.

Applications include identifying environmental risk factors, clarifying gene–environment interactions, and informing prevention and policy. The field faces challenges such as exposure misclassification, data heterogeneity and standardization, integration of high-dimensional data, confounding and latency, privacy concerns, and resource demands. Ongoing developments aim to improve measurement accuracy, data sharing, and causal inference.

Overall, the exposome represents a framework for understanding how the environment shapes health across the life course, guiding research in environmental health, epidemiology, and precision public health as technologies advance.