Reduction in allostatic load in older adults is associated with lower all-cause mortality risk: MacArthur studies of successful aging

Objectives: To study the association between change in allostatic load (a risk score constructed from multiple biological markers) over a 2.5-year period and mortality in the following 4.5 years in older adults. Methods: We measured 10 physiologic parameters at baseline (1988) in a cohort of 171 high-functioning, community-dwelling, 70- to 79-year-old adults. These measurements were repeated 2.5 years later, in 1991. Summary allostatic load scores for 1988 and 1991 were created as the weighted sum of the 10 biological markers and their second-order terms. Mortality status (alive or dead) for participants was determined 4.5 years later, in 1995. The association between change in allostatic load score (1988-1991) and subsequent mortality (1991-1995) was studied using logistic regression. Results: Compared with participants whose allostatic load score decreased between 1988 and 1991, individuals whose allostatic load score increased had higher risk of all-cause mortality between 1991 and 1995 (15% versus 5%, p =.047). Adjusted for age and baseline allostatic load, each unit increment in the allostatic load change score was associated with mortality odds ratio of 3.3 (95% confidence interval, 1.1-9.8). Conclusion: Our results suggest that even in older ages, change in risk scores can be followed to improve assessment of mortality risk.