Background and aimHyperuricemia is associated with nonalcoholic fatty liver disease (NAFLD), whereas whether the association differed by hyperuricemia onset age remained unclear. This study sought to investigate the associations of hyperuricemia onset age with the risk of incident NAFLD across adulthood. Methods and resultsBased on Kailuan prospective cohort, our analysis comprised 3318 new-onset hyperuricemia cases from 2006 to 2015 and 3318 age- and sex-matched controls who were randomly selected from the general population. The risk of NAFLD across the onset age groups (<45, 45–54, 55–64, and ≥65 years) were compared using multivariable-adjusted Cox regression models. During a median follow-up of 6.78 years, 744 (22.42%) hyperuricemia participants and 586 (17.66%) normouricemia participants were diagnosed with incident NAFLD. After adjusted for potential confounders, the risk of NAFLD was gradually attenuated with each decade increase in hyperuricemia onset age. The adjusted hazard ratio (95% confidence interval) was 1.62 (1.33–1.97) for hyperuricemia onset age <45 years, 1.26 (1.01–1.57) for age of 45–54 years, 1.24 (1.00–1.59) for age of 55–64 years, and 1.19 (0.90–1.71) for age ≥65 years, respectively. The trend remained robust among the multiple sensitivity analyses. ConclusionsThe relative risk of incident NAFLD differed across hyperuricemia onset age-group, and the association was more evident in those with a younger age of hyperuricemia onset, highlighting the importance of performing early strategies on the prevention of NAFLD.