Twenty-Five Years of Firearm Homicides and Suicides Among US Children and Young Adults, 1999 to 2024: Intersectional Surveillance Analysis.

Background: Firearm mortality surveillance relies on aggregate demographic categories or low-dimensional stratifications, obscuring how race, ethnicity, sex, age, and intent intersect to shape risk among youth and young adults. The Centers for Disease Control and Prevention (CDC)'s transition to single-race population estimates created a structural break between historical and contemporary data series. Consequently, the 25-year trajectory of intersectional firearm mortality across changing federal classification frameworks remains uncharacterized. Objective: We aimed to characterize 25-year national trajectories in firearm homicide and suicide across intersecting domains of race or ethnicity, sex, age, and intent among US youth and young adults (aged 0-24 y), identifying specific sociodemographic groups experiencing the highest and most rapidly changing burdens. Methods: This study used the CDC WONDER Underlying Cause of Death database (25-year window from 1999-2024). To address the 2018 transition, a 2-period design was deployed: period 1 (1999 to 2020) used bridged 4-category race data, and period 2 (2018 to 2024) used 6-category single-race data. Crude death rates and disparity ratios (referenced to non-Hispanic White youth) were calculated using the Byar approximation. Average annual percentage changes (AAPCs) were modeled via log-linear regression. Analyses incorporated finalized 2024 CDC WONDER data in January 2026. Results: Among 200,704 firearm deaths among youth aged 0-24 years from 1999 to 2024, overall mortality declined through 2013, reversed in 2014, and rose 28.9% from 2019 to 2020. In 2024, the overall rate declined 12% from 2023 but remained above the 2019 prepandemic baseline. During 2018-2024, Black non-Hispanic male youth experienced the highest pooled firearm homicide rate (44.03 per 100,000; 95% CI 43.46-44.61), 23.8 times the rate among White non-Hispanic males. The annual rates within this cohort increased from 33.28 in 2018 to 53.75 in 2021 before declining to 37.06 in 2024 (AAPC, +2.4%; P=.56), while the Black-to-White disparity ratio widened from 19.3 to 24.4. Black non-Hispanic female youth had the highest female firearm homicide rate (6.03 per 100,000), exceeding male rates in 7 of 12 other demographic groups. American Indian or Alaska Native non-Hispanic male youth experienced the highest pooled firearm suicide rate (11.74 per 100,000). Firearm suicide increased significantly among Black non-Hispanic male youth (AAPC, +9.2%; 95% CI +3.2% to +15.4%; P=.01), with a substantial but nonsignificant upward trend among Black non-Hispanic female youth (AAPC, +11.7%; P=.08), while White non-Hispanic male rates remained stable (AAPC, -0.1%; P=.91). Consequently, the Black-to-White non-Hispanic male suicide rate ratio shifted from 0.67 in 2018 to 1.07 in 2024, marking the first time Black youth rates surpassed White youth rates in modern public health surveillance history. Conclusions: Firearm homicide and suicide among US youth exhibit distinct demographic concentration patterns that are systematically obscured by aggregated public health surveillance. Disaggregated surveillance remains imperative to design targeted prevention strategies.