Abstract
This study analyzed the interrelationships of anemia, depression, and cognition, as well as some of their associated factors to understand the paths to frailty. Data from 2,174 baseline participants of the Brazilian Longitudinal Study of Aging (ELSI-Brazil) were used. Path analysis was used to assess the relationships of exogenous variables (place of residence, education level, number of diseases, diet score, and number of natural teeth), one endogenous variable (frailty), and three mediators (cognition, depression, and hemoglobin level). Cognition and hemoglobin level showed a negative path to frailty, while depressive symptoms showed a positive path. Among the exogenous variables, rural area had a negative effect on hemoglobin, depressive symptoms, and frailty; a higher education level showed a positive path to cognition; number of diseases showed a negative path to hemoglobin and a positive path to depressive symptoms and frailty; diet score showed a negative path to hemoglobin and depressive symptoms; number of teeth had a positive effect on cognition and hemoglobin and a negative effect on frailty. Two paths without direct effects had significant indirect effects - rural area showed an indirect relationship with cognition via hemoglobin and depressive symptoms; and education level showed an indirect path to frailty, mediated by the three intermediate variables. These results show complex interrelationships of frailty, hemoglobin, cognition, and depressive symptoms, which help understand the syndrome in a broad way and support the planning of more comprehensive prevention and intervention measures.