Carga alostática e desempenho físico em idosos: análise transversal da coorte IMIAS - International Mobility in Aging Study (IMIAS)

Abstract

INTRODUCTION: Allostatic Load (AL) reflects the cumulative impact of chronic stress on the body and is an important indicator of physiological adaptation to adversities throughout life. In older adults, AL is associated with increased vulnerability to chronic conditions, cognitive deficits, and depressive symptoms. Physical performance may also be linked to elevated AL levels, which can directly influence the quality of life and functional health of this population. OBJECTIVE: To evaluate the association between Allostatic Load (AL) and physical performance scores in older adults from four locations of the International Mobility in Aging Study (IMIAS). METHODS: This thesis comprises a cross-sectional analytical study with data from 1,101 participants aged over 65 years from three countries (Canada, Brazil, and Colombia). Three multiple linear regression models were developed and adjusted for age, socioeconomic status (SES), chronic conditions, depressive symptomatology, and cognitive function to estimate the independent association between the AL index and physical performance, measured by the Short Physical Performance Battery (SPPB) scores. Subsequently, a mediation analysis was conducted to examine the total, direct, and indirect effects of AL on the SPPB scores. RESULTS: In the four IMIAS study locations, AL was inversely associated with physical performance, where higher AL levels corresponded to lower SPPB scores (β: -0.234; Std: 0.033; p-value: <0.001). Indirect effects were observed between age, SES, and chronic conditions with AL and SPPB scores, while chronic conditions showed a total effect on SPPB scores mediated by AL. No significant indirect effects of depressive symptoms and cognitive deficits on SPPB scores were identified. CONCLUSION: The study demonstrated that increased AL levels are associated with poor physical performance in older adults across different socioeconomic aging profiles. AL plays a mediating role between chronic conditions, depressive symptoms, cognitive state, and physical performance, with socioeconomic status also influencing this relationship.