Nicole Betty Johnson1, Erica Jones2, Bruce Ovbiagele3, Daniela Markovic4, Amy Towfighi5
1Neurology, Harbor UCLA, 2Neurology, UT Southwestern, 3Neurology, UCSF, 4Internal Medicine, UCLA, 5Neurology, USC
Objective:
To assess the relationship between allostatic load and its impact on all-cause mortality, cardiovascular mortality, and mortality after stroke.
Background:
Allostatic load index (ALI) is often utilized to evaluate the physiologic response to stress. This study seeks to assess the impact of ALI on mortality outcomes in stroke survivors and how race, ethnicity, and social factors impact these relationships.
Design/Methods:
Using data from the third National Health and Nutritional Examination Survey (NHANES III, 1988-1994) and the 2015 Linked Mortality File (National Death Index), we selected adults aged ≥ 25 years with self-reported stroke. We computed the weighted prevalence of each ALI category to obtain nationally representative estimates with higher ALI corresponding to a higher stress burden. We evaluated the relationship between ALI category and mortality outcomes using the Cox proportional hazard model considering the survey design variables, adjusting for age, sex, race/ethnicity, education, marital status, and income.
Results:
15,567 individuals were included in this study. Of 414 individuals with a reported history of stroke, there were 11.8% ALI ≤ 1, 22.1% ALI = 2, and 66.1% ALI ≥3. Higher ALI correlated with male sex, older age, lower education, married or widowed status, and lower income. In the population with prior stroke, those with ALI ≥ 3 had 2.7 times higher adjusted all-cause mortality (HR: 2.7, CI: 1.5 - 4.9, p-value: 0.01) and 4.5 times higher adjusted cardiovascular mortality (HR: 4.5, CI: 1.4-14.3, p-value: 0.01) compared to those with ALI ≤1. In the general population, the ALI ≥ 3 group had 1.8 times higher adjusted stroke mortality (HR: 1.8, CI: 1.0-3.1, p-value: 0.04).
Conclusions:
Baseline higher allostatic load is associated with greater all-cause and cardiovascular mortality in stroke survivors, in addition to greater stroke mortality in stroke survivors and within the general population. This study highlights the importance of developing interventions to address stress after stroke.