Cognitive Impairment and Physical Activity in Old Age: The Impact on All-Cause Mortality in a 15-Year Follow-Up of the Bambuí Cohort Study of Aging

Abstract

Background: Cognitive impairment increases while physical activity decreases the mortality risk in the elderly. In this study, hypothesize that physical activity among the elderly with cognitive impairment is associated with a lower risk of all-cause mortality. Methods: We included a total of 147 community‐dwelling older adults with cognitive impairment from the baseline of the Bambui Cohort Study of Aging and followed‐up for a median of 9.6 years. We evaluated the physical activity by a self-reported question, which considers how many times participants either walk to exercise, or do gymnastics, or practice sports for at least 20-30 min in the previous 90 days. The date of death was computed by reviewing death certificates. We used Cox's proportional hazards models to evaluate the risk of mortality in those participants. Findings: Participants with cognitive impairment and non-physical activity had a higher risk for mortality in the unadjusted analysis (HR: 2.34; 95% CI: 1.02– 5.39), and the association remained in the final model (HR: 3.21; 95% CI: 1.29-7.99). Interpretation: This study found lower mortality risk among subjects with cognitive impairment but physically active as compared to non-active participants. Funding Statement: The funding is provided by Financiadora de Estudos e Projetos (FINEP), Conselho Nacional de Desenvolvimento Cientifico e Tecnologicos (CNPq), and Fundacao de Amparo a Pesquisa do Estado de Minas Gerais (FAPEMIG). Prof. Blay, Prof. Firmo, Prof. Lima‐Costa, and Prof. Laks received grants from the National Council for Scientific and Technological Development (CNPq; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico—305274/2014‐ 7). Prof. Castro-Costa currently receives research support from the Medical Research Council (MR/T037423/1). Declaration of Interests: The authors declare that there is no conflict of interest. Ethics Approval Statement: The project was approved by the Ethical Committee of the Fundacao Oswaldo Cruz, Brazil.