Deficit Accumulation

This chapter examines frailty from the perspective of deficit accumulation. With age, individuals and various species accumulate deficits at molecular, cellular, and systemic levels, ultimately leading to frailty. The number of accumulated deficits emerges as a key determinant of survival, outweighing their specific nature. This approach challenges conventional risk factor models by underscoring frailty’s role in disease expression, including conditions like cardiovascular mortality and late-life dementia. Established in 2001, the Frailty Index (FI) quantifies an individual’s frailty by counting health deficits. Widely used in research, clinical practice, and health policy, how the FI behaves has become a focus in many quantitative disciplines. The chapter also delves into the dynamics of frailty during acute illness, emphasizing the need for further research and clinical tools to assess frailty dynamics during these episodes. It further explores the connection between frailty and social vulnerability, revealing complex interactions across different cultures and life stages.