Highlight
• In 29,105 women followed for 24 years, higher ultraprocessed food (UPF) intake was associated with greater odds of early‑onset conventional colorectal adenomas (highest vs lowest quintile AOR 1.45; 95% CI, 1.19–1.77).
• UPF intake (median 5.7 servings/day) explained a substantial portion of daily energy (≈35%) in this cohort; associations for serrated lesions were null.
