Abstract Background Breast cancer remains a major global health concern. This study aims to assess the epidemiological trends of breast cancer, with a focus on mortality rates, primary risk factors, and their associations with age, time period, and birth cohort. Methods Mortality data were obtained from the Global Burden of Disease Study 2021. An age-period-cohort model was employed to analyze trends in breast cancer mortality and its primary risk factors. Results Globally, breast cancer outcomes remained poor between 1992 and 2021, with an estimated 660925.3 deaths in 2021. Mortality rates declined significantly in high and high-middle socio-demographic index (SDI) countries [-1.56%, 95% CI (-1.7 to -1.43)], [-1.03% (-1.11 to -0.94), respectively], but increases markedly in low-middle SDI countries [1.18% (1.13 to 1.23)], with little change in other regions. A global shift in breast cancer-related deaths from younger to older age groups was observed, and mortality increased sharply with advancing age. Positive period and cohort effects were primarily seen in high and high-middle SDI countries, whereas adverse effects were more common in lower-SDI regions. Diets high in red meat emerged as the leading risk factor for breast cancer mortality worldwide, although favorable trends were noted in high and high-middle SDI countries. Conclusions Despite a global decline in breast cancer mortality, many countries continue to experience unfavorable period and cohort effects. A notable rise in mortality among individuals aged 80 and older was observed across all SDI quintiles, underscoring the urgent need to strengthen healthcare systems for aging breast cancer populations worldwide.