Exposome-Wide Association Study

An exposome-wide association study (ExWAS), originally introduced as the Environment-Wide Association Study, applies the logic of the genome-wide association study to the environment. Where a GWAS scans hundreds of thousands of genetic variants for association with a trait, an ExWAS scans a broad panel of measured environmental exposures — nutrients, pollutants, chemical biomarkers, infectious markers, and behaviors — against a health outcome, fitting one adjusted regression per exposure and then rigorously controlling the multiple-testing burden across the whole set. The approach was demonstrated by Chirag Patel, Jayanta Bhattacharya, and Atul Butte in 2010 on type 2 diabetes using NHANES data, and it operationalizes Christopher Wild's 2005 concept of the 'exposome': the totality of environmental exposures complementing the genome. ExWAS turns environmental epidemiology from a one-exposure-at-a-time enterprise into a systematic, hypothesis-generating discovery scan.