International Journal of Women's Health · Oct 16, 2026

Global, Regional, and National Burden of Early-Onset Breast Cancer in Women, 1990-2021: GBD 2021 Analysis of Trends, Modifiable Risk Factors, and Health Inequalities

By Zhou X, Zhong X, Liu M et al.

BACKGROUND: Early-onset breast cancer (EOBC) affects women aged 15-44 years during reproductive and economically active life stages. We quantified global, regional, and national EOBC burden from 1990 to 2021, including temporal inflection points, modifiable risks, and health inequalities. METHODS: Using Global Burden of Disease (GBD) 2021 estimates for 204 countries and territories, we analyzed incidence, prevalence, mortality, and disability-adjusted life years (DALYs) among women aged 15-44 years as age-standardized rates. Joinpoint regression estimated annual and average percent changes (APCs, AAPCs); population attributable fractions (PAFs) and the Socio-demographic Index (SDI) characterized risk-factor burden and inequalities. RESULTS: In 2021, an estimated 344,924 EOBC cases occurred globally (age-standardized incidence rate: 9.63 per 100,000). Incidence increased (AAPC: +0.81%), while global mortality changed little. Joinpoint regression identified an acceleration in prevalence growth after 2012 (APC +1.62%). Among SDI strata, Low-middle SDI regions increased fastest (AAPC: +2.25%); geographically, North Africa and the Middle East (+2.90%) and South Asia (+2.44%) led the increases. Mortality declined in high-SDI regions (-1.80%) but rose in low-middle-SDI regions (+1.15%), reflecting persistent inequalities. Incidence rose in all three age strata, fastest at 40-44 years (AAPC +0.96% vs +0.70% and +0.30%), and only that band showed a rising DALY trend. High fasting plasma glucose, smoking, and alcohol use were the leading attributable risks; high body mass index showed negative PAFs in some high-SDI regions, a model-based signal rather than a protective effect, and its crude ecological association did not persist after adjustment for SDI. CONCLUSIONS: The burden of EOBC is increasing across the age range, with the steepest growth in regions undergoing demographic, reproductive, and lifestyle transitions. These findings support age-sensitive prevention, clearer surveillance, and equitable access to timely diagnosis and multidisciplinary care.

doi.org/10.2147/ijwh.s633378Open accessPubMed 42904133Populations