Plasma proteins derived from specific organs can estimate organ age and mortality, but their sensitivity to environmental factors and their robustness in forecasting onset of organ diseases and mortality remain unclear. To address this gap, we estimate the biological age of 11 organs using plasma proteomics data (2,916 proteins) from 44,498 individuals in the UK Biobank. Organ age estimates were sensitive to lifestyle factors and medications and were associated with future onset (within 17 yearsʼ follow-up) of a range of diseases, including heart failure, chronic obstructive pulmonary disease, type 2 diabetes and Alzheimer’s disease. Notably, having an especially aged brain posed a risk of Alzheimer’s disease (hazard ratio (HR) = 3.1) that was similar to carrying one copy of APOE4, the strongest genetic risk factor for sporadic Alzheimer’s disease, whereas a youthful brain (HR = 0.26) provided protection that was similar to carrying two copies of APOE2, independent of APOE genotype.
