Risk and Protective Factors for Cognitive Decline in Brazilian Lower Educated Older Adults: A 15-year follow-up study using group-based trajectory modelling

Background

Patterns of cognitive change and modifiable factors for cognitive decline versus stable cognitive trajectories have rarely been described in lower-educated older adults.

Objectives

We aimed to identify long-term trajectories of cognitive functioning and possible factors associated with cognitive decline.

Design and participants

We used data of 1,042 adults aged ≥ 60 participating in the Health, Welfare and Aging Study (SABE), São Paulo, Brazil, without cognitive impairment at baseline. Data were collected across four waves (2000-2015). Group-based trajectory modelling was used to identify cognitive trajectories. Associations with socioeconomic variables, childhood background, lifestyle, and cardiovascular risk factors were explored using weighted multinomial logistic regressions.

Measurements

The abbreviated Mini-Mental State Examination was used to measure cognition.

Results

Three cognitive trajectories were identified: stable (n= 754, 68.6%), mild-decline (n= 183, 20.8%), and strong-decline (n= 105, 10.7%). At baseline, respondents in the strong-decline group were more likely to be older than those with stable and mild-decline trajectories. Furthermore, participants in both the mild and strong-decline groups were more likely to have no schooling, be divorced/separated, receive less than 4 monthly wages, and be underweight (BMI < 18.5) compared to the stable group. Finally, the mild-decline group were more likely to have lived in rural areas during childhood than participants located in a stable trajectory.

Conclusions

Our findings suggest that interventions to reduce cognitive decline for low-educated older adults might include both addressing inequalities and improving modifiable risk factor burden.