This paper, authored by Ron Brookmeyer, Elizabeth Johnson, Kathryn Ziegler-Graham, and H. Michael Arrighi, forecasts the global burden of Alzheimer's disease and evaluates the potential impact of interventions that delay disease onset or progression. Using a stochastic multi-state model, the authors predict that the worldwide prevalence of Alzheimer's disease will quadruple from 26.6 million in 2006 to 106.8 million by 2050, with 1 in 85 persons worldwide living with the disease. The study estimates that about 43% of prevalent cases require a high level of care, equivalent to that of a nursing home. Interventions that delay both disease onset and progression by a modest 1 year could reduce the number of cases by nearly 9.2 million in 2050, primarily due to a decrease in the number of cases needing high-level care. The authors emphasize the importance of modest advances in therapeutic and preventive strategies to significantly reduce the global burden of Alzheimer's disease as the world's population ages.This paper, authored by Ron Brookmeyer, Elizabeth Johnson, Kathryn Ziegler-Graham, and H. Michael Arrighi, forecasts the global burden of Alzheimer's disease and evaluates the potential impact of interventions that delay disease onset or progression. Using a stochastic multi-state model, the authors predict that the worldwide prevalence of Alzheimer's disease will quadruple from 26.6 million in 2006 to 106.8 million by 2050, with 1 in 85 persons worldwide living with the disease. The study estimates that about 43% of prevalent cases require a high level of care, equivalent to that of a nursing home. Interventions that delay both disease onset and progression by a modest 1 year could reduce the number of cases by nearly 9.2 million in 2050, primarily due to a decrease in the number of cases needing high-level care. The authors emphasize the importance of modest advances in therapeutic and preventive strategies to significantly reduce the global burden of Alzheimer's disease as the world's population ages.