Relationship between advanced activities of daily living and cognitive decline in Community-Dwelling Elderly Individuals in Brazil
METHODS: This was a longitudinal study with a sample of non-institutionalized older adults who participated in the second (2006) and third (2010) waves of the Health, Wellbeing and Aging cohort study in Sao Paulo, Brazil. Cognitive decline was measured using a modified Mini-Mental State Examination. Advanced Activities of Daily Living covered 11 activities, which involves superior cognitive functions (e.g. activities with abilities to travel and plan travelling, participate in groups or community movements, drive, plan events etc). Other covariates included in the study were the following baseline characteristics: socioeconomic conditions, general health and functional disability. Statistical analysis included descriptive analyses of frequency, bivariate and multiple analyses using Poisson Regression. Stata 11.0 was used for the analyses and a correction for the design effect was made using the “survey” command to analyze data originating from a complex sample.
RESULTS: The final sample consisted of 819 individuals adults aged 60 and older. After five years, the incidence of cognitive decline was 7.9%. From the multiple regression analysis it was found that individuals with higher number of a-ADL at baseline had lower risk of cognitive decline at follow-up [RR 0.89(95% CI 0.80-.98)]. Other characteristics that were associated with a higher risk of cognitive decline in the final model were: age (70+ years) [RR 3.81(95% CI 1.58-9.17)] and difficulty in the Instrumental Activities of Daily Living [RR 2.73 (95% CI 1.57-4.74)]. Individuals with 8+ years of schooling had lower risk of decline [RR 0.28 (95% CI 0.10-0.81)].
CONCLUSIONS: The number of Advanced Activities of Daily Living was a significant predictor of cognitive decline independent of socioeconomic conditions and general health factors.