Behavioral gains offset by metabolic drift: A 34-year global profile of breast cancer risk attribution.

e12765 Background: Breast cancer (BC) remains one of the most common malignancies globally and a leading cause of female mortality and disability. Although advancements in screening and treatment have improved outcomes in high- income countries, the burden attributable to modifiable risk factors—particularly behavioral risks (BRs) and metabolic risks (MRs) varies substantially over time, regions, and socio-demographic strata. Methods: We utilized the Global Burden of Disease (GBD) 2023 framework to quantify global, regional, and age-specific BC burden attributable to BRs and MRs across 204 countries from 1990 to 2023. Outcomes included deaths, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life years (DALYs). Results: Globally, BC deaths attributable to all risk factors increased from 120,728 (95% UI: 71,625–165,691) in 1990 to 232,506 (133,617–322,736) in 2023 (EAPC +1.81%). YLLs rose from 3.55 to 6.43 million (+1.58%), and YLDs from 226,705 to 509,110 (+2.38%). Age-standardized mortality rates (ASMRs) declined in HI (−1.61%), High-Socio-demographic Index (SDI) (−1.51%), SEA, EA, and Oceania (−0.66%), High-middle SDI (−0.50%), and CE, EE and CA (−0.37%); remained stable in Low SDI (−0.17%); and increased in SA (+1.84%), NEMA (+1.21%), SA (+1.01%), Low-middle SDI (+0.61%), Middle SDI (+0.55%), and LA and Caribbean (+0.16%). From 1990-2023, BC burden attributable to BRs declined across all metrics: Deaths (EAPC −1.06%), DALYs (−0.97%), YLLs (−1.02%), and YLDs (−0.34%). Conversely, MR-attributable burden remained stable or slightly increased: Deaths (−0.27%), YLLs (−0.26%), YLDs (+0.41%). Age-stratified analysis showed that BR- attributable DALY rates declined in: 20–54 years (−0.35%), and ≥55 years (−1.04%). In contrast, MR- attributable DALY rates increased in 20–54 years (+0.88%) and slightly declined in ≥55 years (−0.16%). Conclusions: The global burden of BC attributable to BRs consistently declined, while that due to MRs remained stable or rose—particularly among younger and middle-aged adults. These findings highlight the shifting landscape of modifiable exposures and underscore the urgent need for targeted MR reduction strategies, especially in low- and middle-income countries (LMICs) where BC mortality is on the rise. Region Diet high in red meat High alcohol use High body-mass index High fasting plasma glucose Low physical activity Secondhand smoke Smoking High-income (HI) -1.59 -1.86 -0.99 -0.9 -1.44 -3.14 -2.26 Latin America (LA) and Caribbean 0.31 0.92 1.46 0.44 0.45 -1.83 -1.79 North Africa and Middle East (NEMA) 1.08 -2.4 2.83 2.83 1.39 0.86 0.19 South Asia (SA) 2 0.46 5.56 2.64 1.55 0.35 0.29 Southeast Asia (SEA), East Asia (EA), and Oceania -0.62 -1.18 0.98 -1.04 -0.2 -0.95 -2.05 Sub-Saharan Africa (SA) 1.8 1.71 3.54 2.99 1.94 1.01 0.17 Central Europe (CE), Eastern Europe (EE), and Central Asia (CA) -0.85 -1.02 0.5 0.29 -0.34 -1.94 -0.36