Exposome

The exposome is the totality of environmental exposures an individual encounters from conception to death — spanning chemical, physical, biological, lifestyle, and social factors — and was coined by Christopher Wild in 2005 as a conceptual counterpart to the genome. Wild subsequently elaborated three overlapping domains: a general external environment (urban-rural setting, climate, socioeconomic position), a specific external environment (diet, physical activity, tobacco, occupational hazards, pollutants), and an internal environment (metabolic state, microbiome composition, oxidative stress, inflammation). Measuring the exposome requires integrating wearable sensors, biomarkers in blood and urine (adducts, metabolites), geographic exposure data, and multi-omic profiling — an approach called exposomics. Evidence from large epidemiological datasets consistently links chronic exposomic burden to accelerated biological aging via oxidative DNA damage, mitochondrial dysfunction, cellular senescence, and epigenetic clock advancement; a WHO global environmental burden-of-disease analysis (Prüss-Üstün et al., 2016) attributes roughly 24% of all deaths globally to modifiable environmental factors. Associations between specific exposomic components and aging outcomes are well-documented in human cohorts, yet disentangling causal pathways from confounding — and aggregating across thousands of co-occurring exposures simultaneously — remains an active methodological challenge; the field is associational at the aggregate level and still developing causal inference tools.