Cumulative Index of Health Deficiencies as a Characteristic of Long Life

Abstract

OBJECTIVES: To describe the accumulation of aging‐associated health disorders using a cumulative measure known as a frailty index (FI) and to evaluate its ability to differentiate long‐ and short‐life phenotypes as well as the FI's connection to aging‐associated processes in older people. DESIGN: Retrospective cross‐sectional and longitudinal studies. SETTING: The National Long‐Term Care Survey (NLTCS) data that assessed health and functioning of U.S. older individuals (≥65) in 1982, 1984, 1989, 1994, and 1999 were analyzed. The NLTCS sample in each survey represents a mixture of longitudinal and cross‐sectional components. PARTICIPANTS: Approximately 5,000 individuals in each survey. MEASUREMENTS: A cumulative index of health and well‐being deficiencies (disabilities, signs, diseases) was calculated as a count of deficits observed in an individual divided by the total number of all considered deficits. RESULTS: Men and women who died before the age of 75 and those who died after the age of 85 exhibited remarkably similar FI frequency patterns despite the 10‐year age difference between age profiles in these samples. Long life is consistently characterized in longitudinal analyses by lower FIs. FI dynamics are found to be strongly sex sensitive. CONCLUSION: The FI appears to be a sensitive age‐independent indicator of sex‐specific physiological decline in aging individuals and a sex‐specific discriminator of survival chances. The FI is a promising characteristic suitable for improving sex‐sensitive forecasts of risks of adverse health outcomes in older people.