Among UKB participants recruited in England (n = 436,891), an exposome-wide association study (XWAS) for all-cause mortality was conducted using the discovery and replication sets. The discovery and replication sets were then pooled, and further analyses were conducted in the full sample to identify and remove replicated exposures that were sensitive to reverse causation (disease sensitivity) and mismeasurement (PheWAS per exposure). The remaining exposures were then tested cross-sectionally for associations with a previously developed proteomic aging clock (n = 45,441). We then conducted a final sensitivity analysis in the participants recruited in England (n = 436,891) to remove exposures sensitive to correlation bias (cluster analysis).